7356 lines
190 KiB
C
7356 lines
190 KiB
C
/*
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* Generic process-grouping system.
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*
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* Based originally on the cpuset system, extracted by Paul Menage
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* Copyright (C) 2006 Google, Inc
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*
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* Notifications support
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* Copyright (C) 2009 Nokia Corporation
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* Author: Kirill A. Shutemov
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*
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* Copyright notices from the original cpuset code:
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* --------------------------------------------------
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* Copyright (C) 2003 BULL SA.
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* Copyright (C) 2004-2006 Silicon Graphics, Inc.
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*
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* Portions derived from Patrick Mochel's sysfs code.
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* sysfs is Copyright (c) 2001-3 Patrick Mochel
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*
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* 2003-10-10 Written by Simon Derr.
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* 2003-10-22 Updates by Stephen Hemminger.
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* 2004 May-July Rework by Paul Jackson.
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* ---------------------------------------------------
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file COPYING in the main directory of the Linux
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* distribution for more details.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include "cgroup-internal.h"
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#include <linux/cpu.h>
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#include <linux/cred.h>
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#include <linux/errno.h>
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#include <linux/init_task.h>
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#include <linux/kernel.h>
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#include <linux/magic.h>
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#include <linux/mutex.h>
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#include <linux/mount.h>
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#include <linux/pagemap.h>
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#include <linux/proc_fs.h>
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#include <linux/rcupdate.h>
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#include <linux/sched.h>
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#include <linux/sched/task.h>
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#include <linux/slab.h>
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#include <linux/spinlock.h>
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#include <linux/percpu-rwsem.h>
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#include <linux/string.h>
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#include <linux/hashtable.h>
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#include <linux/idr.h>
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#include <linux/kthread.h>
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#include <linux/atomic.h>
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#include <linux/cpuset.h>
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#include <linux/proc_ns.h>
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#include <linux/nsproxy.h>
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#include <linux/file.h>
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#include <linux/fs_parser.h>
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#include <linux/sched/cputime.h>
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#include <linux/psi.h>
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#include <net/sock.h>
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#include <linux/rqm.h>
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#include <linux/mbuf.h>
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#include <linux/sli.h>
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#include <linux/backing-dev.h>
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#define CREATE_TRACE_POINTS
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#include <trace/events/cgroup.h>
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#define CGROUP_FILE_NAME_MAX (MAX_CGROUP_TYPE_NAMELEN + \
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MAX_CFTYPE_NAME + 2)
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/* let's not notify more than 100 times per second */
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#define CGROUP_FILE_NOTIFY_MIN_INTV DIV_ROUND_UP(HZ, 100)
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/*
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* cgroup_mutex is the master lock. Any modification to cgroup or its
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* hierarchy must be performed while holding it.
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*
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* css_set_lock protects task->cgroups pointer, the list of css_set
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* objects, and the chain of tasks off each css_set.
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*
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* These locks are exported if CONFIG_PROVE_RCU so that accessors in
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* cgroup.h can use them for lockdep annotations.
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*/
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DEFINE_MUTEX(cgroup_mutex);
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DEFINE_SPINLOCK(css_set_lock);
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#ifdef CONFIG_PROVE_RCU
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EXPORT_SYMBOL_GPL(cgroup_mutex);
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EXPORT_SYMBOL_GPL(css_set_lock);
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#endif
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DEFINE_SPINLOCK(trace_cgroup_path_lock);
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char trace_cgroup_path[TRACE_CGROUP_PATH_LEN];
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bool cgroup_debug __read_mostly;
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/*
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* Protects cgroup_idr and css_idr so that IDs can be released without
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* grabbing cgroup_mutex.
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*/
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static DEFINE_SPINLOCK(cgroup_idr_lock);
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/*
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* Protects cgroup_file->kn for !self csses. It synchronizes notifications
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* against file removal/re-creation across css hiding.
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*/
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static DEFINE_SPINLOCK(cgroup_file_kn_lock);
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DEFINE_PERCPU_RWSEM(cgroup_threadgroup_rwsem);
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#define cgroup_assert_mutex_or_rcu_locked() \
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RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
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!lockdep_is_held(&cgroup_mutex), \
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"cgroup_mutex or RCU read lock required");
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/*
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* cgroup destruction makes heavy use of work items and there can be a lot
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* of concurrent destructions. Use a separate workqueue so that cgroup
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* destruction work items don't end up filling up max_active of system_wq
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* which may lead to deadlock.
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*/
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static struct workqueue_struct *cgroup_destroy_wq;
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/* generate an array of cgroup subsystem pointers */
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#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys,
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struct cgroup_subsys *cgroup_subsys[] = {
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#include <linux/cgroup_subsys.h>
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};
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#undef SUBSYS
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/* array of cgroup subsystem names */
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#define SUBSYS(_x) [_x ## _cgrp_id] = #_x,
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static const char *cgroup_subsys_name[] = {
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#include <linux/cgroup_subsys.h>
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};
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#undef SUBSYS
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/* array of static_keys for cgroup_subsys_enabled() and cgroup_subsys_on_dfl() */
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#define SUBSYS(_x) \
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DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_enabled_key); \
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DEFINE_STATIC_KEY_TRUE(_x ## _cgrp_subsys_on_dfl_key); \
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EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_enabled_key); \
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EXPORT_SYMBOL_GPL(_x ## _cgrp_subsys_on_dfl_key);
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#include <linux/cgroup_subsys.h>
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#undef SUBSYS
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#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys_enabled_key,
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static struct static_key_true *cgroup_subsys_enabled_key[] = {
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#include <linux/cgroup_subsys.h>
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};
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#undef SUBSYS
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#define SUBSYS(_x) [_x ## _cgrp_id] = &_x ## _cgrp_subsys_on_dfl_key,
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static struct static_key_true *cgroup_subsys_on_dfl_key[] = {
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#include <linux/cgroup_subsys.h>
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};
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#undef SUBSYS
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static DEFINE_PER_CPU(struct cgroup_rstat_cpu, cgrp_dfl_root_rstat_cpu);
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/*
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* The default hierarchy, reserved for the subsystems that are otherwise
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* unattached - it never has more than a single cgroup, and all tasks are
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* part of that cgroup.
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*/
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struct cgroup_root cgrp_dfl_root = { .cgrp.rstat_cpu = &cgrp_dfl_root_rstat_cpu };
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EXPORT_SYMBOL_GPL(cgrp_dfl_root);
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/*
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* The default hierarchy always exists but is hidden until mounted for the
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* first time. This is for backward compatibility.
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*/
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static bool cgrp_dfl_visible;
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/* some controllers are not supported in the default hierarchy */
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static u16 cgrp_dfl_inhibit_ss_mask;
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/* some controllers are implicitly enabled on the default hierarchy */
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static u16 cgrp_dfl_implicit_ss_mask;
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/* some controllers can be threaded on the default hierarchy */
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static u16 cgrp_dfl_threaded_ss_mask;
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/* The list of hierarchy roots */
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LIST_HEAD(cgroup_roots);
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static int cgroup_root_count;
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int sysctl_qos_mbuf_enable = 0;
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/* hierarchy ID allocation and mapping, protected by cgroup_mutex */
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static DEFINE_IDR(cgroup_hierarchy_idr);
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/*
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* Assign a monotonically increasing serial number to csses. It guarantees
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* cgroups with bigger numbers are newer than those with smaller numbers.
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* Also, as csses are always appended to the parent's ->children list, it
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* guarantees that sibling csses are always sorted in the ascending serial
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* number order on the list. Protected by cgroup_mutex.
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*/
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static u64 css_serial_nr_next = 1;
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/*
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* These bitmasks identify subsystems with specific features to avoid
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* having to do iterative checks repeatedly.
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*/
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static u16 have_fork_callback __read_mostly;
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static u16 have_exit_callback __read_mostly;
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static u16 have_release_callback __read_mostly;
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static u16 have_canfork_callback __read_mostly;
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/* cgroup namespace for init task */
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struct cgroup_namespace init_cgroup_ns = {
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.count = REFCOUNT_INIT(2),
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.user_ns = &init_user_ns,
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.ns.ops = &cgroupns_operations,
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.ns.inum = PROC_CGROUP_INIT_INO,
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.root_cset = &init_css_set,
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};
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static struct file_system_type cgroup2_fs_type;
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static struct cftype cgroup_base_files[];
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static int cgroup_apply_control(struct cgroup *cgrp);
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static void cgroup_finalize_control(struct cgroup *cgrp, int ret);
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static void css_task_iter_skip(struct css_task_iter *it,
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struct task_struct *task);
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static int cgroup_destroy_locked(struct cgroup *cgrp);
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static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
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struct cgroup_subsys *ss);
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static void css_release(struct percpu_ref *ref);
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static void kill_css(struct cgroup_subsys_state *css);
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static int cgroup_addrm_files(struct cgroup_subsys_state *css,
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struct cgroup *cgrp, struct cftype cfts[],
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bool is_add);
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/**
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* cgroup_ssid_enabled - cgroup subsys enabled test by subsys ID
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* @ssid: subsys ID of interest
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*
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* cgroup_subsys_enabled() can only be used with literal subsys names which
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* is fine for individual subsystems but unsuitable for cgroup core. This
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* is slower static_key_enabled() based test indexed by @ssid.
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*/
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bool cgroup_ssid_enabled(int ssid)
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{
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if (CGROUP_SUBSYS_COUNT == 0)
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return false;
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return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
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}
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/**
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* cgroup_on_dfl - test whether a cgroup is on the default hierarchy
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* @cgrp: the cgroup of interest
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*
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* The default hierarchy is the v2 interface of cgroup and this function
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* can be used to test whether a cgroup is on the default hierarchy for
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* cases where a subsystem should behave differnetly depending on the
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* interface version.
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*
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* The set of behaviors which change on the default hierarchy are still
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* being determined and the mount option is prefixed with __DEVEL__.
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*
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* List of changed behaviors:
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*
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* - Mount options "noprefix", "xattr", "clone_children", "release_agent"
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* and "name" are disallowed.
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*
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* - When mounting an existing superblock, mount options should match.
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*
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* - Remount is disallowed.
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*
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* - rename(2) is disallowed.
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*
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* - "tasks" is removed. Everything should be at process granularity. Use
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* "cgroup.procs" instead.
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*
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* - "cgroup.procs" is not sorted. pids will be unique unless they got
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* recycled inbetween reads.
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*
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* - "release_agent" and "notify_on_release" are removed. Replacement
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* notification mechanism will be implemented.
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*
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* - "cgroup.clone_children" is removed.
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*
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* - "cgroup.subtree_populated" is available. Its value is 0 if the cgroup
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* and its descendants contain no task; otherwise, 1. The file also
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* generates kernfs notification which can be monitored through poll and
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* [di]notify when the value of the file changes.
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*
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* - cpuset: tasks will be kept in empty cpusets when hotplug happens and
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* take masks of ancestors with non-empty cpus/mems, instead of being
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* moved to an ancestor.
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*
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* - cpuset: a task can be moved into an empty cpuset, and again it takes
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* masks of ancestors.
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*
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* - memcg: use_hierarchy is on by default and the cgroup file for the flag
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* is not created.
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*
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* - blkcg: blk-throttle becomes properly hierarchical.
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*
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* - debug: disallowed on the default hierarchy.
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*/
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bool cgroup_on_dfl(const struct cgroup *cgrp)
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{
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return cgrp->root == &cgrp_dfl_root;
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}
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/* IDR wrappers which synchronize using cgroup_idr_lock */
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static int cgroup_idr_alloc(struct idr *idr, void *ptr, int start, int end,
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gfp_t gfp_mask)
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{
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int ret;
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idr_preload(gfp_mask);
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spin_lock_bh(&cgroup_idr_lock);
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ret = idr_alloc(idr, ptr, start, end, gfp_mask & ~__GFP_DIRECT_RECLAIM);
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spin_unlock_bh(&cgroup_idr_lock);
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idr_preload_end();
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return ret;
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}
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static void *cgroup_idr_replace(struct idr *idr, void *ptr, int id)
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{
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void *ret;
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spin_lock_bh(&cgroup_idr_lock);
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ret = idr_replace(idr, ptr, id);
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spin_unlock_bh(&cgroup_idr_lock);
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return ret;
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}
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static void cgroup_idr_remove(struct idr *idr, int id)
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{
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spin_lock_bh(&cgroup_idr_lock);
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idr_remove(idr, id);
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spin_unlock_bh(&cgroup_idr_lock);
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}
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static bool cgroup_has_tasks(struct cgroup *cgrp)
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{
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return cgrp->nr_populated_csets;
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}
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bool cgroup_is_threaded(struct cgroup *cgrp)
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{
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return cgrp->dom_cgrp != cgrp;
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}
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/* can @cgrp host both domain and threaded children? */
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static bool cgroup_is_mixable(struct cgroup *cgrp)
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{
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/*
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* Root isn't under domain level resource control exempting it from
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* the no-internal-process constraint, so it can serve as a thread
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* root and a parent of resource domains at the same time.
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*/
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return !cgroup_parent(cgrp);
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}
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/* can @cgrp become a thread root? should always be true for a thread root */
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static bool cgroup_can_be_thread_root(struct cgroup *cgrp)
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{
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/* mixables don't care */
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if (cgroup_is_mixable(cgrp))
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return true;
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/* domain roots can't be nested under threaded */
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if (cgroup_is_threaded(cgrp))
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return false;
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/* can only have either domain or threaded children */
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if (cgrp->nr_populated_domain_children)
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return false;
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/* and no domain controllers can be enabled */
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if (cgrp->subtree_control & ~cgrp_dfl_threaded_ss_mask)
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return false;
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return true;
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}
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/* is @cgrp root of a threaded subtree? */
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bool cgroup_is_thread_root(struct cgroup *cgrp)
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{
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/* thread root should be a domain */
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if (cgroup_is_threaded(cgrp))
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return false;
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/* a domain w/ threaded children is a thread root */
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if (cgrp->nr_threaded_children)
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return true;
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/*
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* A domain which has tasks and explicit threaded controllers
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* enabled is a thread root.
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*/
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if (cgroup_has_tasks(cgrp) &&
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(cgrp->subtree_control & cgrp_dfl_threaded_ss_mask))
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return true;
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return false;
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}
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/* a domain which isn't connected to the root w/o brekage can't be used */
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static bool cgroup_is_valid_domain(struct cgroup *cgrp)
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{
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/* the cgroup itself can be a thread root */
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if (cgroup_is_threaded(cgrp))
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return false;
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/* but the ancestors can't be unless mixable */
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while ((cgrp = cgroup_parent(cgrp))) {
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if (!cgroup_is_mixable(cgrp) && cgroup_is_thread_root(cgrp))
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return false;
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if (cgroup_is_threaded(cgrp))
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return false;
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}
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return true;
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}
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/* subsystems visibly enabled on a cgroup */
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static u16 cgroup_control(struct cgroup *cgrp)
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{
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struct cgroup *parent = cgroup_parent(cgrp);
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u16 root_ss_mask = cgrp->root->subsys_mask;
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if (parent) {
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u16 ss_mask = parent->subtree_control;
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/* threaded cgroups can only have threaded controllers */
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if (cgroup_is_threaded(cgrp))
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ss_mask &= cgrp_dfl_threaded_ss_mask;
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return ss_mask;
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}
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if (cgroup_on_dfl(cgrp))
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root_ss_mask &= ~(cgrp_dfl_inhibit_ss_mask |
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cgrp_dfl_implicit_ss_mask);
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return root_ss_mask;
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}
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/* subsystems enabled on a cgroup */
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static u16 cgroup_ss_mask(struct cgroup *cgrp)
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{
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struct cgroup *parent = cgroup_parent(cgrp);
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if (parent) {
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u16 ss_mask = parent->subtree_ss_mask;
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/* threaded cgroups can only have threaded controllers */
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if (cgroup_is_threaded(cgrp))
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ss_mask &= cgrp_dfl_threaded_ss_mask;
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return ss_mask;
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}
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return cgrp->root->subsys_mask;
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}
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/**
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* cgroup_css - obtain a cgroup's css for the specified subsystem
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* @cgrp: the cgroup of interest
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* @ss: the subsystem of interest (%NULL returns @cgrp->self)
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*
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* Return @cgrp's css (cgroup_subsys_state) associated with @ss. This
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* function must be called either under cgroup_mutex or rcu_read_lock() and
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* the caller is responsible for pinning the returned css if it wants to
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* keep accessing it outside the said locks. This function may return
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* %NULL if @cgrp doesn't have @subsys_id enabled.
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*/
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static struct cgroup_subsys_state *cgroup_css(struct cgroup *cgrp,
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struct cgroup_subsys *ss)
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{
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if (ss)
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return rcu_dereference_check(cgrp->subsys[ss->id],
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lockdep_is_held(&cgroup_mutex));
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else
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return &cgrp->self;
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}
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/**
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* cgroup_tryget_css - try to get a cgroup's css for the specified subsystem
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* @cgrp: the cgroup of interest
|
|
* @ss: the subsystem of interest
|
|
*
|
|
* Find and get @cgrp's css assocaited with @ss. If the css doesn't exist
|
|
* or is offline, %NULL is returned.
|
|
*/
|
|
static struct cgroup_subsys_state *cgroup_tryget_css(struct cgroup *cgrp,
|
|
struct cgroup_subsys *ss)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
|
|
rcu_read_lock();
|
|
css = cgroup_css(cgrp, ss);
|
|
if (css && !css_tryget_online(css))
|
|
css = NULL;
|
|
rcu_read_unlock();
|
|
|
|
return css;
|
|
}
|
|
|
|
/**
|
|
* cgroup_e_css_by_mask - obtain a cgroup's effective css for the specified ss
|
|
* @cgrp: the cgroup of interest
|
|
* @ss: the subsystem of interest (%NULL returns @cgrp->self)
|
|
*
|
|
* Similar to cgroup_css() but returns the effective css, which is defined
|
|
* as the matching css of the nearest ancestor including self which has @ss
|
|
* enabled. If @ss is associated with the hierarchy @cgrp is on, this
|
|
* function is guaranteed to return non-NULL css.
|
|
*/
|
|
static struct cgroup_subsys_state *cgroup_e_css_by_mask(struct cgroup *cgrp,
|
|
struct cgroup_subsys *ss)
|
|
{
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
if (!ss)
|
|
return &cgrp->self;
|
|
|
|
/*
|
|
* This function is used while updating css associations and thus
|
|
* can't test the csses directly. Test ss_mask.
|
|
*/
|
|
while (!(cgroup_ss_mask(cgrp) & (1 << ss->id))) {
|
|
cgrp = cgroup_parent(cgrp);
|
|
if (!cgrp)
|
|
return NULL;
|
|
}
|
|
|
|
return cgroup_css(cgrp, ss);
|
|
}
|
|
|
|
/**
|
|
* cgroup_e_css - obtain a cgroup's effective css for the specified subsystem
|
|
* @cgrp: the cgroup of interest
|
|
* @ss: the subsystem of interest
|
|
*
|
|
* Find and get the effective css of @cgrp for @ss. The effective css is
|
|
* defined as the matching css of the nearest ancestor including self which
|
|
* has @ss enabled. If @ss is not mounted on the hierarchy @cgrp is on,
|
|
* the root css is returned, so this function always returns a valid css.
|
|
*
|
|
* The returned css is not guaranteed to be online, and therefore it is the
|
|
* callers responsiblity to tryget a reference for it.
|
|
*/
|
|
struct cgroup_subsys_state *cgroup_e_css(struct cgroup *cgrp,
|
|
struct cgroup_subsys *ss)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
|
|
do {
|
|
css = cgroup_css(cgrp, ss);
|
|
|
|
if (css)
|
|
return css;
|
|
cgrp = cgroup_parent(cgrp);
|
|
} while (cgrp);
|
|
|
|
return init_css_set.subsys[ss->id];
|
|
}
|
|
|
|
/**
|
|
* cgroup_get_e_css - get a cgroup's effective css for the specified subsystem
|
|
* @cgrp: the cgroup of interest
|
|
* @ss: the subsystem of interest
|
|
*
|
|
* Find and get the effective css of @cgrp for @ss. The effective css is
|
|
* defined as the matching css of the nearest ancestor including self which
|
|
* has @ss enabled. If @ss is not mounted on the hierarchy @cgrp is on,
|
|
* the root css is returned, so this function always returns a valid css.
|
|
* The returned css must be put using css_put().
|
|
*/
|
|
struct cgroup_subsys_state *cgroup_get_e_css(struct cgroup *cgrp,
|
|
struct cgroup_subsys *ss)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
|
|
rcu_read_lock();
|
|
|
|
do {
|
|
css = cgroup_css(cgrp, ss);
|
|
|
|
if (css && css_tryget_online(css))
|
|
goto out_unlock;
|
|
cgrp = cgroup_parent(cgrp);
|
|
} while (cgrp);
|
|
|
|
css = init_css_set.subsys[ss->id];
|
|
css_get(css);
|
|
out_unlock:
|
|
rcu_read_unlock();
|
|
return css;
|
|
}
|
|
|
|
static void cgroup_get_live(struct cgroup *cgrp)
|
|
{
|
|
WARN_ON_ONCE(cgroup_is_dead(cgrp));
|
|
css_get(&cgrp->self);
|
|
}
|
|
|
|
/**
|
|
* __cgroup_task_count - count the number of tasks in a cgroup. The caller
|
|
* is responsible for taking the css_set_lock.
|
|
* @cgrp: the cgroup in question
|
|
*/
|
|
int __cgroup_task_count(const struct cgroup *cgrp)
|
|
{
|
|
int count = 0;
|
|
struct cgrp_cset_link *link;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
list_for_each_entry(link, &cgrp->cset_links, cset_link)
|
|
count += link->cset->nr_tasks;
|
|
|
|
return count;
|
|
}
|
|
|
|
/**
|
|
* cgroup_task_count - count the number of tasks in a cgroup.
|
|
* @cgrp: the cgroup in question
|
|
*/
|
|
int cgroup_task_count(const struct cgroup *cgrp)
|
|
{
|
|
int count;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
count = __cgroup_task_count(cgrp);
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
return count;
|
|
}
|
|
|
|
struct cgroup_subsys_state *of_css(struct kernfs_open_file *of)
|
|
{
|
|
struct cgroup *cgrp = of->kn->parent->priv;
|
|
struct cftype *cft = of_cft(of);
|
|
|
|
/*
|
|
* This is open and unprotected implementation of cgroup_css().
|
|
* seq_css() is only called from a kernfs file operation which has
|
|
* an active reference on the file. Because all the subsystem
|
|
* files are drained before a css is disassociated with a cgroup,
|
|
* the matching css from the cgroup's subsys table is guaranteed to
|
|
* be and stay valid until the enclosing operation is complete.
|
|
*/
|
|
if (cft->ss)
|
|
return rcu_dereference_raw(cgrp->subsys[cft->ss->id]);
|
|
else
|
|
return &cgrp->self;
|
|
}
|
|
EXPORT_SYMBOL_GPL(of_css);
|
|
|
|
/**
|
|
* for_each_css - iterate all css's of a cgroup
|
|
* @css: the iteration cursor
|
|
* @ssid: the index of the subsystem, CGROUP_SUBSYS_COUNT after reaching the end
|
|
* @cgrp: the target cgroup to iterate css's of
|
|
*
|
|
* Should be called under cgroup_[tree_]mutex.
|
|
*/
|
|
#define for_each_css(css, ssid, cgrp) \
|
|
for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++) \
|
|
if (!((css) = rcu_dereference_check( \
|
|
(cgrp)->subsys[(ssid)], \
|
|
lockdep_is_held(&cgroup_mutex)))) { } \
|
|
else
|
|
|
|
/**
|
|
* for_each_e_css - iterate all effective css's of a cgroup
|
|
* @css: the iteration cursor
|
|
* @ssid: the index of the subsystem, CGROUP_SUBSYS_COUNT after reaching the end
|
|
* @cgrp: the target cgroup to iterate css's of
|
|
*
|
|
* Should be called under cgroup_[tree_]mutex.
|
|
*/
|
|
#define for_each_e_css(css, ssid, cgrp) \
|
|
for ((ssid) = 0; (ssid) < CGROUP_SUBSYS_COUNT; (ssid)++) \
|
|
if (!((css) = cgroup_e_css_by_mask(cgrp, \
|
|
cgroup_subsys[(ssid)]))) \
|
|
; \
|
|
else
|
|
|
|
/**
|
|
* do_each_subsys_mask - filter for_each_subsys with a bitmask
|
|
* @ss: the iteration cursor
|
|
* @ssid: the index of @ss, CGROUP_SUBSYS_COUNT after reaching the end
|
|
* @ss_mask: the bitmask
|
|
*
|
|
* The block will only run for cases where the ssid-th bit (1 << ssid) of
|
|
* @ss_mask is set.
|
|
*/
|
|
#define do_each_subsys_mask(ss, ssid, ss_mask) do { \
|
|
unsigned long __ss_mask = (ss_mask); \
|
|
if (!CGROUP_SUBSYS_COUNT) { /* to avoid spurious gcc warning */ \
|
|
(ssid) = 0; \
|
|
break; \
|
|
} \
|
|
for_each_set_bit(ssid, &__ss_mask, CGROUP_SUBSYS_COUNT) { \
|
|
(ss) = cgroup_subsys[ssid]; \
|
|
{
|
|
|
|
#define while_each_subsys_mask() \
|
|
} \
|
|
} \
|
|
} while (false)
|
|
|
|
/* iterate over child cgrps, lock should be held throughout iteration */
|
|
#define cgroup_for_each_live_child(child, cgrp) \
|
|
list_for_each_entry((child), &(cgrp)->self.children, self.sibling) \
|
|
if (({ lockdep_assert_held(&cgroup_mutex); \
|
|
cgroup_is_dead(child); })) \
|
|
; \
|
|
else
|
|
|
|
/* walk live descendants in preorder */
|
|
#define cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) \
|
|
css_for_each_descendant_pre((d_css), cgroup_css((cgrp), NULL)) \
|
|
if (({ lockdep_assert_held(&cgroup_mutex); \
|
|
(dsct) = (d_css)->cgroup; \
|
|
cgroup_is_dead(dsct); })) \
|
|
; \
|
|
else
|
|
|
|
/* walk live descendants in postorder */
|
|
#define cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) \
|
|
css_for_each_descendant_post((d_css), cgroup_css((cgrp), NULL)) \
|
|
if (({ lockdep_assert_held(&cgroup_mutex); \
|
|
(dsct) = (d_css)->cgroup; \
|
|
cgroup_is_dead(dsct); })) \
|
|
; \
|
|
else
|
|
|
|
/*
|
|
* The default css_set - used by init and its children prior to any
|
|
* hierarchies being mounted. It contains a pointer to the root state
|
|
* for each subsystem. Also used to anchor the list of css_sets. Not
|
|
* reference-counted, to improve performance when child cgroups
|
|
* haven't been created.
|
|
*/
|
|
struct css_set init_css_set = {
|
|
.refcount = REFCOUNT_INIT(1),
|
|
.dom_cset = &init_css_set,
|
|
.tasks = LIST_HEAD_INIT(init_css_set.tasks),
|
|
.mg_tasks = LIST_HEAD_INIT(init_css_set.mg_tasks),
|
|
.dying_tasks = LIST_HEAD_INIT(init_css_set.dying_tasks),
|
|
.task_iters = LIST_HEAD_INIT(init_css_set.task_iters),
|
|
.threaded_csets = LIST_HEAD_INIT(init_css_set.threaded_csets),
|
|
.cgrp_links = LIST_HEAD_INIT(init_css_set.cgrp_links),
|
|
.mg_src_preload_node = LIST_HEAD_INIT(init_css_set.mg_src_preload_node),
|
|
.mg_dst_preload_node = LIST_HEAD_INIT(init_css_set.mg_dst_preload_node),
|
|
.mg_node = LIST_HEAD_INIT(init_css_set.mg_node),
|
|
|
|
/*
|
|
* The following field is re-initialized when this cset gets linked
|
|
* in cgroup_init(). However, let's initialize the field
|
|
* statically too so that the default cgroup can be accessed safely
|
|
* early during boot.
|
|
*/
|
|
.dfl_cgrp = &cgrp_dfl_root.cgrp,
|
|
};
|
|
|
|
static int css_set_count = 1; /* 1 for init_css_set */
|
|
|
|
static bool css_set_threaded(struct css_set *cset)
|
|
{
|
|
return cset->dom_cset != cset;
|
|
}
|
|
|
|
/**
|
|
* css_set_populated - does a css_set contain any tasks?
|
|
* @cset: target css_set
|
|
*
|
|
* css_set_populated() should be the same as !!cset->nr_tasks at steady
|
|
* state. However, css_set_populated() can be called while a task is being
|
|
* added to or removed from the linked list before the nr_tasks is
|
|
* properly updated. Hence, we can't just look at ->nr_tasks here.
|
|
*/
|
|
static bool css_set_populated(struct css_set *cset)
|
|
{
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
return !list_empty(&cset->tasks) || !list_empty(&cset->mg_tasks);
|
|
}
|
|
|
|
/**
|
|
* cgroup_update_populated - update the populated count of a cgroup
|
|
* @cgrp: the target cgroup
|
|
* @populated: inc or dec populated count
|
|
*
|
|
* One of the css_sets associated with @cgrp is either getting its first
|
|
* task or losing the last. Update @cgrp->nr_populated_* accordingly. The
|
|
* count is propagated towards root so that a given cgroup's
|
|
* nr_populated_children is zero iff none of its descendants contain any
|
|
* tasks.
|
|
*
|
|
* @cgrp's interface file "cgroup.populated" is zero if both
|
|
* @cgrp->nr_populated_csets and @cgrp->nr_populated_children are zero and
|
|
* 1 otherwise. When the sum changes from or to zero, userland is notified
|
|
* that the content of the interface file has changed. This can be used to
|
|
* detect when @cgrp and its descendants become populated or empty.
|
|
*/
|
|
static void cgroup_update_populated(struct cgroup *cgrp, bool populated)
|
|
{
|
|
struct cgroup *child = NULL;
|
|
int adj = populated ? 1 : -1;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
do {
|
|
bool was_populated = cgroup_is_populated(cgrp);
|
|
|
|
if (!child) {
|
|
cgrp->nr_populated_csets += adj;
|
|
} else {
|
|
if (cgroup_is_threaded(child))
|
|
cgrp->nr_populated_threaded_children += adj;
|
|
else
|
|
cgrp->nr_populated_domain_children += adj;
|
|
}
|
|
|
|
if (was_populated == cgroup_is_populated(cgrp))
|
|
break;
|
|
|
|
cgroup1_check_for_release(cgrp);
|
|
TRACE_CGROUP_PATH(notify_populated, cgrp,
|
|
cgroup_is_populated(cgrp));
|
|
cgroup_file_notify(&cgrp->events_file);
|
|
|
|
child = cgrp;
|
|
cgrp = cgroup_parent(cgrp);
|
|
} while (cgrp);
|
|
}
|
|
|
|
/**
|
|
* css_set_update_populated - update populated state of a css_set
|
|
* @cset: target css_set
|
|
* @populated: whether @cset is populated or depopulated
|
|
*
|
|
* @cset is either getting the first task or losing the last. Update the
|
|
* populated counters of all associated cgroups accordingly.
|
|
*/
|
|
static void css_set_update_populated(struct css_set *cset, bool populated)
|
|
{
|
|
struct cgrp_cset_link *link;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
list_for_each_entry(link, &cset->cgrp_links, cgrp_link)
|
|
cgroup_update_populated(link->cgrp, populated);
|
|
}
|
|
|
|
/*
|
|
* @task is leaving, advance task iterators which are pointing to it so
|
|
* that they can resume at the next position. Advancing an iterator might
|
|
* remove it from the list, use safe walk. See css_task_iter_skip() for
|
|
* details.
|
|
*/
|
|
static void css_set_skip_task_iters(struct css_set *cset,
|
|
struct task_struct *task)
|
|
{
|
|
struct css_task_iter *it, *pos;
|
|
|
|
list_for_each_entry_safe(it, pos, &cset->task_iters, iters_node)
|
|
css_task_iter_skip(it, task);
|
|
}
|
|
|
|
/**
|
|
* css_set_move_task - move a task from one css_set to another
|
|
* @task: task being moved
|
|
* @from_cset: css_set @task currently belongs to (may be NULL)
|
|
* @to_cset: new css_set @task is being moved to (may be NULL)
|
|
* @use_mg_tasks: move to @to_cset->mg_tasks instead of ->tasks
|
|
*
|
|
* Move @task from @from_cset to @to_cset. If @task didn't belong to any
|
|
* css_set, @from_cset can be NULL. If @task is being disassociated
|
|
* instead of moved, @to_cset can be NULL.
|
|
*
|
|
* This function automatically handles populated counter updates and
|
|
* css_task_iter adjustments but the caller is responsible for managing
|
|
* @from_cset and @to_cset's reference counts.
|
|
*/
|
|
static void css_set_move_task(struct task_struct *task,
|
|
struct css_set *from_cset, struct css_set *to_cset,
|
|
bool use_mg_tasks)
|
|
{
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
if (to_cset && !css_set_populated(to_cset))
|
|
css_set_update_populated(to_cset, true);
|
|
|
|
if (from_cset) {
|
|
WARN_ON_ONCE(list_empty(&task->cg_list));
|
|
|
|
css_set_skip_task_iters(from_cset, task);
|
|
list_del_init(&task->cg_list);
|
|
if (!css_set_populated(from_cset))
|
|
css_set_update_populated(from_cset, false);
|
|
} else {
|
|
WARN_ON_ONCE(!list_empty(&task->cg_list));
|
|
}
|
|
|
|
if (to_cset) {
|
|
/*
|
|
* We are synchronized through cgroup_threadgroup_rwsem
|
|
* against PF_EXITING setting such that we can't race
|
|
* against cgroup_exit() changing the css_set to
|
|
* init_css_set and dropping the old one.
|
|
*/
|
|
WARN_ON_ONCE(task->flags & PF_EXITING);
|
|
|
|
cgroup_move_task(task, to_cset);
|
|
list_add_tail(&task->cg_list, use_mg_tasks ? &to_cset->mg_tasks :
|
|
&to_cset->tasks);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* hash table for cgroup groups. This improves the performance to find
|
|
* an existing css_set. This hash doesn't (currently) take into
|
|
* account cgroups in empty hierarchies.
|
|
*/
|
|
#define CSS_SET_HASH_BITS 7
|
|
static DEFINE_HASHTABLE(css_set_table, CSS_SET_HASH_BITS);
|
|
|
|
static unsigned long css_set_hash(struct cgroup_subsys_state *css[])
|
|
{
|
|
unsigned long key = 0UL;
|
|
struct cgroup_subsys *ss;
|
|
int i;
|
|
|
|
for_each_subsys(ss, i)
|
|
key += (unsigned long)css[i];
|
|
key = (key >> 16) ^ key;
|
|
|
|
return key;
|
|
}
|
|
|
|
void put_css_set_locked(struct css_set *cset)
|
|
{
|
|
struct cgrp_cset_link *link, *tmp_link;
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
if (!refcount_dec_and_test(&cset->refcount))
|
|
return;
|
|
|
|
WARN_ON_ONCE(!list_empty(&cset->threaded_csets));
|
|
|
|
/* This css_set is dead. unlink it and release cgroup and css refs */
|
|
for_each_subsys(ss, ssid) {
|
|
list_del(&cset->e_cset_node[ssid]);
|
|
css_put(cset->subsys[ssid]);
|
|
}
|
|
hash_del(&cset->hlist);
|
|
css_set_count--;
|
|
|
|
list_for_each_entry_safe(link, tmp_link, &cset->cgrp_links, cgrp_link) {
|
|
list_del(&link->cset_link);
|
|
list_del(&link->cgrp_link);
|
|
if (cgroup_parent(link->cgrp))
|
|
cgroup_put(link->cgrp);
|
|
kfree(link);
|
|
}
|
|
|
|
if (css_set_threaded(cset)) {
|
|
list_del(&cset->threaded_csets_node);
|
|
put_css_set_locked(cset->dom_cset);
|
|
}
|
|
|
|
kfree_rcu(cset, rcu_head);
|
|
}
|
|
|
|
/**
|
|
* compare_css_sets - helper function for find_existing_css_set().
|
|
* @cset: candidate css_set being tested
|
|
* @old_cset: existing css_set for a task
|
|
* @new_cgrp: cgroup that's being entered by the task
|
|
* @template: desired set of css pointers in css_set (pre-calculated)
|
|
*
|
|
* Returns true if "cset" matches "old_cset" except for the hierarchy
|
|
* which "new_cgrp" belongs to, for which it should match "new_cgrp".
|
|
*/
|
|
static bool compare_css_sets(struct css_set *cset,
|
|
struct css_set *old_cset,
|
|
struct cgroup *new_cgrp,
|
|
struct cgroup_subsys_state *template[])
|
|
{
|
|
struct cgroup *new_dfl_cgrp;
|
|
struct list_head *l1, *l2;
|
|
|
|
/*
|
|
* On the default hierarchy, there can be csets which are
|
|
* associated with the same set of cgroups but different csses.
|
|
* Let's first ensure that csses match.
|
|
*/
|
|
if (memcmp(template, cset->subsys, sizeof(cset->subsys)))
|
|
return false;
|
|
|
|
|
|
/* @cset's domain should match the default cgroup's */
|
|
if (cgroup_on_dfl(new_cgrp))
|
|
new_dfl_cgrp = new_cgrp;
|
|
else
|
|
new_dfl_cgrp = old_cset->dfl_cgrp;
|
|
|
|
if (new_dfl_cgrp->dom_cgrp != cset->dom_cset->dfl_cgrp)
|
|
return false;
|
|
|
|
/*
|
|
* Compare cgroup pointers in order to distinguish between
|
|
* different cgroups in hierarchies. As different cgroups may
|
|
* share the same effective css, this comparison is always
|
|
* necessary.
|
|
*/
|
|
l1 = &cset->cgrp_links;
|
|
l2 = &old_cset->cgrp_links;
|
|
while (1) {
|
|
struct cgrp_cset_link *link1, *link2;
|
|
struct cgroup *cgrp1, *cgrp2;
|
|
|
|
l1 = l1->next;
|
|
l2 = l2->next;
|
|
/* See if we reached the end - both lists are equal length. */
|
|
if (l1 == &cset->cgrp_links) {
|
|
BUG_ON(l2 != &old_cset->cgrp_links);
|
|
break;
|
|
} else {
|
|
BUG_ON(l2 == &old_cset->cgrp_links);
|
|
}
|
|
/* Locate the cgroups associated with these links. */
|
|
link1 = list_entry(l1, struct cgrp_cset_link, cgrp_link);
|
|
link2 = list_entry(l2, struct cgrp_cset_link, cgrp_link);
|
|
cgrp1 = link1->cgrp;
|
|
cgrp2 = link2->cgrp;
|
|
/* Hierarchies should be linked in the same order. */
|
|
BUG_ON(cgrp1->root != cgrp2->root);
|
|
|
|
/*
|
|
* If this hierarchy is the hierarchy of the cgroup
|
|
* that's changing, then we need to check that this
|
|
* css_set points to the new cgroup; if it's any other
|
|
* hierarchy, then this css_set should point to the
|
|
* same cgroup as the old css_set.
|
|
*/
|
|
if (cgrp1->root == new_cgrp->root) {
|
|
if (cgrp1 != new_cgrp)
|
|
return false;
|
|
} else {
|
|
if (cgrp1 != cgrp2)
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* find_existing_css_set - init css array and find the matching css_set
|
|
* @old_cset: the css_set that we're using before the cgroup transition
|
|
* @cgrp: the cgroup that we're moving into
|
|
* @template: out param for the new set of csses, should be clear on entry
|
|
*/
|
|
static struct css_set *find_existing_css_set(struct css_set *old_cset,
|
|
struct cgroup *cgrp,
|
|
struct cgroup_subsys_state *template[])
|
|
{
|
|
struct cgroup_root *root = cgrp->root;
|
|
struct cgroup_subsys *ss;
|
|
struct css_set *cset;
|
|
unsigned long key;
|
|
int i;
|
|
|
|
/*
|
|
* Build the set of subsystem state objects that we want to see in the
|
|
* new css_set. while subsystems can change globally, the entries here
|
|
* won't change, so no need for locking.
|
|
*/
|
|
for_each_subsys(ss, i) {
|
|
if (root->subsys_mask & (1UL << i)) {
|
|
/*
|
|
* @ss is in this hierarchy, so we want the
|
|
* effective css from @cgrp.
|
|
*/
|
|
template[i] = cgroup_e_css_by_mask(cgrp, ss);
|
|
} else {
|
|
/*
|
|
* @ss is not in this hierarchy, so we don't want
|
|
* to change the css.
|
|
*/
|
|
template[i] = old_cset->subsys[i];
|
|
}
|
|
}
|
|
|
|
key = css_set_hash(template);
|
|
hash_for_each_possible(css_set_table, cset, hlist, key) {
|
|
if (!compare_css_sets(cset, old_cset, cgrp, template))
|
|
continue;
|
|
|
|
/* This css_set matches what we need */
|
|
return cset;
|
|
}
|
|
|
|
/* No existing cgroup group matched */
|
|
return NULL;
|
|
}
|
|
|
|
static void free_cgrp_cset_links(struct list_head *links_to_free)
|
|
{
|
|
struct cgrp_cset_link *link, *tmp_link;
|
|
|
|
list_for_each_entry_safe(link, tmp_link, links_to_free, cset_link) {
|
|
list_del(&link->cset_link);
|
|
kfree(link);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* allocate_cgrp_cset_links - allocate cgrp_cset_links
|
|
* @count: the number of links to allocate
|
|
* @tmp_links: list_head the allocated links are put on
|
|
*
|
|
* Allocate @count cgrp_cset_link structures and chain them on @tmp_links
|
|
* through ->cset_link. Returns 0 on success or -errno.
|
|
*/
|
|
static int allocate_cgrp_cset_links(int count, struct list_head *tmp_links)
|
|
{
|
|
struct cgrp_cset_link *link;
|
|
int i;
|
|
|
|
INIT_LIST_HEAD(tmp_links);
|
|
|
|
for (i = 0; i < count; i++) {
|
|
link = kzalloc(sizeof(*link), GFP_KERNEL);
|
|
if (!link) {
|
|
free_cgrp_cset_links(tmp_links);
|
|
return -ENOMEM;
|
|
}
|
|
list_add(&link->cset_link, tmp_links);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* link_css_set - a helper function to link a css_set to a cgroup
|
|
* @tmp_links: cgrp_cset_link objects allocated by allocate_cgrp_cset_links()
|
|
* @cset: the css_set to be linked
|
|
* @cgrp: the destination cgroup
|
|
*/
|
|
static void link_css_set(struct list_head *tmp_links, struct css_set *cset,
|
|
struct cgroup *cgrp)
|
|
{
|
|
struct cgrp_cset_link *link;
|
|
|
|
BUG_ON(list_empty(tmp_links));
|
|
|
|
if (cgroup_on_dfl(cgrp))
|
|
cset->dfl_cgrp = cgrp;
|
|
|
|
link = list_first_entry(tmp_links, struct cgrp_cset_link, cset_link);
|
|
link->cset = cset;
|
|
link->cgrp = cgrp;
|
|
|
|
/*
|
|
* Always add links to the tail of the lists so that the lists are
|
|
* in choronological order.
|
|
*/
|
|
list_move_tail(&link->cset_link, &cgrp->cset_links);
|
|
list_add_tail(&link->cgrp_link, &cset->cgrp_links);
|
|
|
|
if (cgroup_parent(cgrp))
|
|
cgroup_get_live(cgrp);
|
|
}
|
|
|
|
/**
|
|
* find_css_set - return a new css_set with one cgroup updated
|
|
* @old_cset: the baseline css_set
|
|
* @cgrp: the cgroup to be updated
|
|
*
|
|
* Return a new css_set that's equivalent to @old_cset, but with @cgrp
|
|
* substituted into the appropriate hierarchy.
|
|
*/
|
|
static struct css_set *find_css_set(struct css_set *old_cset,
|
|
struct cgroup *cgrp)
|
|
{
|
|
struct cgroup_subsys_state *template[CGROUP_SUBSYS_COUNT] = { };
|
|
struct css_set *cset;
|
|
struct list_head tmp_links;
|
|
struct cgrp_cset_link *link;
|
|
struct cgroup_subsys *ss;
|
|
unsigned long key;
|
|
int ssid;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/* First see if we already have a cgroup group that matches
|
|
* the desired set */
|
|
spin_lock_irq(&css_set_lock);
|
|
cset = find_existing_css_set(old_cset, cgrp, template);
|
|
if (cset)
|
|
get_css_set(cset);
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
if (cset)
|
|
return cset;
|
|
|
|
cset = kzalloc(sizeof(*cset), GFP_KERNEL);
|
|
if (!cset)
|
|
return NULL;
|
|
|
|
/* Allocate all the cgrp_cset_link objects that we'll need */
|
|
if (allocate_cgrp_cset_links(cgroup_root_count, &tmp_links) < 0) {
|
|
kfree(cset);
|
|
return NULL;
|
|
}
|
|
|
|
refcount_set(&cset->refcount, 1);
|
|
cset->dom_cset = cset;
|
|
INIT_LIST_HEAD(&cset->tasks);
|
|
INIT_LIST_HEAD(&cset->mg_tasks);
|
|
INIT_LIST_HEAD(&cset->dying_tasks);
|
|
INIT_LIST_HEAD(&cset->task_iters);
|
|
INIT_LIST_HEAD(&cset->threaded_csets);
|
|
INIT_HLIST_NODE(&cset->hlist);
|
|
INIT_LIST_HEAD(&cset->cgrp_links);
|
|
INIT_LIST_HEAD(&cset->mg_src_preload_node);
|
|
INIT_LIST_HEAD(&cset->mg_dst_preload_node);
|
|
INIT_LIST_HEAD(&cset->mg_node);
|
|
|
|
/* Copy the set of subsystem state objects generated in
|
|
* find_existing_css_set() */
|
|
memcpy(cset->subsys, template, sizeof(cset->subsys));
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
/* Add reference counts and links from the new css_set. */
|
|
list_for_each_entry(link, &old_cset->cgrp_links, cgrp_link) {
|
|
struct cgroup *c = link->cgrp;
|
|
|
|
if (c->root == cgrp->root)
|
|
c = cgrp;
|
|
link_css_set(&tmp_links, cset, c);
|
|
}
|
|
|
|
BUG_ON(!list_empty(&tmp_links));
|
|
|
|
css_set_count++;
|
|
|
|
/* Add @cset to the hash table */
|
|
key = css_set_hash(cset->subsys);
|
|
hash_add(css_set_table, &cset->hlist, key);
|
|
|
|
for_each_subsys(ss, ssid) {
|
|
struct cgroup_subsys_state *css = cset->subsys[ssid];
|
|
|
|
list_add_tail(&cset->e_cset_node[ssid],
|
|
&css->cgroup->e_csets[ssid]);
|
|
css_get(css);
|
|
}
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/*
|
|
* If @cset should be threaded, look up the matching dom_cset and
|
|
* link them up. We first fully initialize @cset then look for the
|
|
* dom_cset. It's simpler this way and safe as @cset is guaranteed
|
|
* to stay empty until we return.
|
|
*/
|
|
if (cgroup_is_threaded(cset->dfl_cgrp)) {
|
|
struct css_set *dcset;
|
|
|
|
dcset = find_css_set(cset, cset->dfl_cgrp->dom_cgrp);
|
|
if (!dcset) {
|
|
put_css_set(cset);
|
|
return NULL;
|
|
}
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
cset->dom_cset = dcset;
|
|
list_add_tail(&cset->threaded_csets_node,
|
|
&dcset->threaded_csets);
|
|
spin_unlock_irq(&css_set_lock);
|
|
}
|
|
|
|
return cset;
|
|
}
|
|
|
|
struct cgroup_root *cgroup_root_from_kf(struct kernfs_root *kf_root)
|
|
{
|
|
struct cgroup *root_cgrp = kf_root->kn->priv;
|
|
|
|
return root_cgrp->root;
|
|
}
|
|
|
|
static int cgroup_init_root_id(struct cgroup_root *root)
|
|
{
|
|
int id;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
id = idr_alloc_cyclic(&cgroup_hierarchy_idr, root, 0, 0, GFP_KERNEL);
|
|
if (id < 0)
|
|
return id;
|
|
|
|
root->hierarchy_id = id;
|
|
return 0;
|
|
}
|
|
|
|
static void cgroup_exit_root_id(struct cgroup_root *root)
|
|
{
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
idr_remove(&cgroup_hierarchy_idr, root->hierarchy_id);
|
|
}
|
|
|
|
void cgroup_free_root(struct cgroup_root *root)
|
|
{
|
|
if (root) {
|
|
idr_destroy(&root->cgroup_idr);
|
|
kfree(root);
|
|
}
|
|
}
|
|
|
|
static void cgroup_destroy_root(struct cgroup_root *root)
|
|
{
|
|
struct cgroup *cgrp = &root->cgrp;
|
|
struct cgrp_cset_link *link, *tmp_link;
|
|
|
|
trace_cgroup_destroy_root(root);
|
|
|
|
cgroup_lock_and_drain_offline(&cgrp_dfl_root.cgrp);
|
|
|
|
BUG_ON(atomic_read(&root->nr_cgrps));
|
|
BUG_ON(!list_empty(&cgrp->self.children));
|
|
|
|
/* Rebind all subsystems back to the default hierarchy */
|
|
WARN_ON(rebind_subsystems(&cgrp_dfl_root, root->subsys_mask));
|
|
|
|
/*
|
|
* Release all the links from cset_links to this hierarchy's
|
|
* root cgroup
|
|
*/
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
list_for_each_entry_safe(link, tmp_link, &cgrp->cset_links, cset_link) {
|
|
list_del(&link->cset_link);
|
|
list_del(&link->cgrp_link);
|
|
kfree(link);
|
|
}
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
if (!list_empty(&root->root_list)) {
|
|
list_del(&root->root_list);
|
|
cgroup_root_count--;
|
|
}
|
|
|
|
cgroup_exit_root_id(root);
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
|
|
kernfs_destroy_root(root->kf_root);
|
|
cgroup_free_root(root);
|
|
}
|
|
|
|
/*
|
|
* look up cgroup associated with current task's cgroup namespace on the
|
|
* specified hierarchy
|
|
*/
|
|
static struct cgroup *
|
|
current_cgns_cgroup_from_root(struct cgroup_root *root)
|
|
{
|
|
struct cgroup *res = NULL;
|
|
struct css_set *cset;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
rcu_read_lock();
|
|
|
|
cset = current->nsproxy->cgroup_ns->root_cset;
|
|
if (cset == &init_css_set) {
|
|
res = &root->cgrp;
|
|
} else {
|
|
struct cgrp_cset_link *link;
|
|
|
|
list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
|
|
struct cgroup *c = link->cgrp;
|
|
|
|
if (c->root == root) {
|
|
res = c;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
|
|
BUG_ON(!res);
|
|
return res;
|
|
}
|
|
|
|
/* look up cgroup associated with given css_set on the specified hierarchy */
|
|
static struct cgroup *cset_cgroup_from_root(struct css_set *cset,
|
|
struct cgroup_root *root)
|
|
{
|
|
struct cgroup *res = NULL;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
if (cset == &init_css_set) {
|
|
res = &root->cgrp;
|
|
} else if (root == &cgrp_dfl_root) {
|
|
res = cset->dfl_cgrp;
|
|
} else {
|
|
struct cgrp_cset_link *link;
|
|
|
|
list_for_each_entry(link, &cset->cgrp_links, cgrp_link) {
|
|
struct cgroup *c = link->cgrp;
|
|
|
|
if (c->root == root) {
|
|
res = c;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
BUG_ON(!res);
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* Return the cgroup for "task" from the given hierarchy. Must be
|
|
* called with cgroup_mutex and css_set_lock held.
|
|
*/
|
|
struct cgroup *task_cgroup_from_root(struct task_struct *task,
|
|
struct cgroup_root *root)
|
|
{
|
|
/*
|
|
* No need to lock the task - since we hold cgroup_mutex the
|
|
* task can't change groups, so the only thing that can happen
|
|
* is that it exits and its css is set back to init_css_set.
|
|
*/
|
|
return cset_cgroup_from_root(task_css_set(task), root);
|
|
}
|
|
|
|
/*
|
|
* A task must hold cgroup_mutex to modify cgroups.
|
|
*
|
|
* Any task can increment and decrement the count field without lock.
|
|
* So in general, code holding cgroup_mutex can't rely on the count
|
|
* field not changing. However, if the count goes to zero, then only
|
|
* cgroup_attach_task() can increment it again. Because a count of zero
|
|
* means that no tasks are currently attached, therefore there is no
|
|
* way a task attached to that cgroup can fork (the other way to
|
|
* increment the count). So code holding cgroup_mutex can safely
|
|
* assume that if the count is zero, it will stay zero. Similarly, if
|
|
* a task holds cgroup_mutex on a cgroup with zero count, it
|
|
* knows that the cgroup won't be removed, as cgroup_rmdir()
|
|
* needs that mutex.
|
|
*
|
|
* A cgroup can only be deleted if both its 'count' of using tasks
|
|
* is zero, and its list of 'children' cgroups is empty. Since all
|
|
* tasks in the system use _some_ cgroup, and since there is always at
|
|
* least one task in the system (init, pid == 1), therefore, root cgroup
|
|
* always has either children cgroups and/or using tasks. So we don't
|
|
* need a special hack to ensure that root cgroup cannot be deleted.
|
|
*
|
|
* P.S. One more locking exception. RCU is used to guard the
|
|
* update of a tasks cgroup pointer by cgroup_attach_task()
|
|
*/
|
|
|
|
static struct kernfs_syscall_ops cgroup_kf_syscall_ops;
|
|
|
|
static char *cgroup_file_name(struct cgroup *cgrp, const struct cftype *cft,
|
|
char *buf)
|
|
{
|
|
struct cgroup_subsys *ss = cft->ss;
|
|
|
|
if (cft->ss && !(cft->flags & CFTYPE_NO_PREFIX) &&
|
|
!(cgrp->root->flags & CGRP_ROOT_NOPREFIX)) {
|
|
const char *dbg = (cft->flags & CFTYPE_DEBUG) ? ".__DEBUG__." : "";
|
|
|
|
snprintf(buf, CGROUP_FILE_NAME_MAX, "%s%s.%s",
|
|
dbg, cgroup_on_dfl(cgrp) ? ss->name : ss->legacy_name,
|
|
cft->name);
|
|
} else {
|
|
strscpy(buf, cft->name, CGROUP_FILE_NAME_MAX);
|
|
}
|
|
return buf;
|
|
}
|
|
|
|
/**
|
|
* cgroup_file_mode - deduce file mode of a control file
|
|
* @cft: the control file in question
|
|
*
|
|
* S_IRUGO for read, S_IWUSR for write.
|
|
*/
|
|
static umode_t cgroup_file_mode(const struct cftype *cft)
|
|
{
|
|
umode_t mode = 0;
|
|
|
|
if (cft->read_u64 || cft->read_s64 || cft->seq_show)
|
|
mode |= S_IRUGO;
|
|
|
|
if (cft->write_u64 || cft->write_s64 || cft->write) {
|
|
if (cft->flags & CFTYPE_WORLD_WRITABLE)
|
|
mode |= S_IWUGO;
|
|
else
|
|
mode |= S_IWUSR;
|
|
}
|
|
|
|
return mode;
|
|
}
|
|
|
|
/**
|
|
* cgroup_calc_subtree_ss_mask - calculate subtree_ss_mask
|
|
* @subtree_control: the new subtree_control mask to consider
|
|
* @this_ss_mask: available subsystems
|
|
*
|
|
* On the default hierarchy, a subsystem may request other subsystems to be
|
|
* enabled together through its ->depends_on mask. In such cases, more
|
|
* subsystems than specified in "cgroup.subtree_control" may be enabled.
|
|
*
|
|
* This function calculates which subsystems need to be enabled if
|
|
* @subtree_control is to be applied while restricted to @this_ss_mask.
|
|
*/
|
|
static u16 cgroup_calc_subtree_ss_mask(u16 subtree_control, u16 this_ss_mask)
|
|
{
|
|
u16 cur_ss_mask = subtree_control;
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
cur_ss_mask |= cgrp_dfl_implicit_ss_mask;
|
|
|
|
while (true) {
|
|
u16 new_ss_mask = cur_ss_mask;
|
|
|
|
do_each_subsys_mask(ss, ssid, cur_ss_mask) {
|
|
new_ss_mask |= ss->depends_on;
|
|
} while_each_subsys_mask();
|
|
|
|
/*
|
|
* Mask out subsystems which aren't available. This can
|
|
* happen only if some depended-upon subsystems were bound
|
|
* to non-default hierarchies.
|
|
*/
|
|
new_ss_mask &= this_ss_mask;
|
|
|
|
if (new_ss_mask == cur_ss_mask)
|
|
break;
|
|
cur_ss_mask = new_ss_mask;
|
|
}
|
|
|
|
return cur_ss_mask;
|
|
}
|
|
|
|
/**
|
|
* cgroup_kn_unlock - unlocking helper for cgroup kernfs methods
|
|
* @kn: the kernfs_node being serviced
|
|
*
|
|
* This helper undoes cgroup_kn_lock_live() and should be invoked before
|
|
* the method finishes if locking succeeded. Note that once this function
|
|
* returns the cgroup returned by cgroup_kn_lock_live() may become
|
|
* inaccessible any time. If the caller intends to continue to access the
|
|
* cgroup, it should pin it before invoking this function.
|
|
*/
|
|
void cgroup_kn_unlock(struct kernfs_node *kn)
|
|
{
|
|
struct cgroup *cgrp;
|
|
|
|
if (kernfs_type(kn) == KERNFS_DIR)
|
|
cgrp = kn->priv;
|
|
else
|
|
cgrp = kn->parent->priv;
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
|
|
kernfs_unbreak_active_protection(kn);
|
|
cgroup_put(cgrp);
|
|
}
|
|
|
|
/**
|
|
* cgroup_kn_lock_live - locking helper for cgroup kernfs methods
|
|
* @kn: the kernfs_node being serviced
|
|
* @drain_offline: perform offline draining on the cgroup
|
|
*
|
|
* This helper is to be used by a cgroup kernfs method currently servicing
|
|
* @kn. It breaks the active protection, performs cgroup locking and
|
|
* verifies that the associated cgroup is alive. Returns the cgroup if
|
|
* alive; otherwise, %NULL. A successful return should be undone by a
|
|
* matching cgroup_kn_unlock() invocation. If @drain_offline is %true, the
|
|
* cgroup is drained of offlining csses before return.
|
|
*
|
|
* Any cgroup kernfs method implementation which requires locking the
|
|
* associated cgroup should use this helper. It avoids nesting cgroup
|
|
* locking under kernfs active protection and allows all kernfs operations
|
|
* including self-removal.
|
|
*/
|
|
struct cgroup *cgroup_kn_lock_live(struct kernfs_node *kn, bool drain_offline)
|
|
{
|
|
struct cgroup *cgrp;
|
|
|
|
if (kernfs_type(kn) == KERNFS_DIR)
|
|
cgrp = kn->priv;
|
|
else
|
|
cgrp = kn->parent->priv;
|
|
|
|
/*
|
|
* We're gonna grab cgroup_mutex which nests outside kernfs
|
|
* active_ref. cgroup liveliness check alone provides enough
|
|
* protection against removal. Ensure @cgrp stays accessible and
|
|
* break the active_ref protection.
|
|
*/
|
|
if (!cgroup_tryget(cgrp))
|
|
return NULL;
|
|
kernfs_break_active_protection(kn);
|
|
|
|
if (drain_offline)
|
|
cgroup_lock_and_drain_offline(cgrp);
|
|
else
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
if (!cgroup_is_dead(cgrp))
|
|
return cgrp;
|
|
|
|
cgroup_kn_unlock(kn);
|
|
return NULL;
|
|
}
|
|
|
|
static void cgroup_rm_file(struct cgroup *cgrp, const struct cftype *cft)
|
|
{
|
|
char name[CGROUP_FILE_NAME_MAX];
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
if (cft->file_offset) {
|
|
struct cgroup_subsys_state *css = cgroup_css(cgrp, cft->ss);
|
|
struct cgroup_file *cfile = (void *)css + cft->file_offset;
|
|
|
|
spin_lock_irq(&cgroup_file_kn_lock);
|
|
cfile->kn = NULL;
|
|
spin_unlock_irq(&cgroup_file_kn_lock);
|
|
|
|
del_timer_sync(&cfile->notify_timer);
|
|
}
|
|
|
|
kernfs_remove_by_name(cgrp->kn, cgroup_file_name(cgrp, cft, name));
|
|
}
|
|
|
|
/**
|
|
* css_clear_dir - remove subsys files in a cgroup directory
|
|
* @css: taget css
|
|
*/
|
|
static void css_clear_dir(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup *cgrp = css->cgroup;
|
|
struct cftype *cfts;
|
|
|
|
if (!(css->flags & CSS_VISIBLE))
|
|
return;
|
|
|
|
css->flags &= ~CSS_VISIBLE;
|
|
|
|
if (!css->ss) {
|
|
if (cgroup_on_dfl(cgrp))
|
|
cfts = cgroup_base_files;
|
|
else
|
|
cfts = cgroup1_base_files;
|
|
|
|
cgroup_addrm_files(css, cgrp, cfts, false);
|
|
} else {
|
|
list_for_each_entry(cfts, &css->ss->cfts, node)
|
|
cgroup_addrm_files(css, cgrp, cfts, false);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* css_populate_dir - create subsys files in a cgroup directory
|
|
* @css: target css
|
|
*
|
|
* On failure, no file is added.
|
|
*/
|
|
static int css_populate_dir(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup *cgrp = css->cgroup;
|
|
struct cftype *cfts, *failed_cfts;
|
|
int ret;
|
|
|
|
if ((css->flags & CSS_VISIBLE) || !cgrp->kn)
|
|
return 0;
|
|
|
|
if (!css->ss) {
|
|
if (cgroup_on_dfl(cgrp))
|
|
cfts = cgroup_base_files;
|
|
else
|
|
cfts = cgroup1_base_files;
|
|
|
|
ret = cgroup_addrm_files(&cgrp->self, cgrp, cfts, true);
|
|
if (ret < 0)
|
|
return ret;
|
|
} else {
|
|
list_for_each_entry(cfts, &css->ss->cfts, node) {
|
|
ret = cgroup_addrm_files(css, cgrp, cfts, true);
|
|
if (ret < 0) {
|
|
failed_cfts = cfts;
|
|
goto err;
|
|
}
|
|
}
|
|
}
|
|
|
|
css->flags |= CSS_VISIBLE;
|
|
|
|
return 0;
|
|
err:
|
|
list_for_each_entry(cfts, &css->ss->cfts, node) {
|
|
if (cfts == failed_cfts)
|
|
break;
|
|
cgroup_addrm_files(css, cgrp, cfts, false);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
int rebind_subsystems(struct cgroup_root *dst_root, u16 ss_mask)
|
|
{
|
|
struct cgroup *dcgrp = &dst_root->cgrp;
|
|
struct cgroup_subsys *ss;
|
|
int ssid, i, ret;
|
|
u16 dfl_disable_ss_mask = 0;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
do_each_subsys_mask(ss, ssid, ss_mask) {
|
|
/*
|
|
* If @ss has non-root csses attached to it, can't move.
|
|
* If @ss is an implicit controller, it is exempt from this
|
|
* rule and can be stolen.
|
|
*/
|
|
if (css_next_child(NULL, cgroup_css(&ss->root->cgrp, ss)) &&
|
|
!ss->implicit_on_dfl)
|
|
return -EBUSY;
|
|
|
|
/* can't move between two non-dummy roots either */
|
|
if (ss->root != &cgrp_dfl_root && dst_root != &cgrp_dfl_root)
|
|
return -EBUSY;
|
|
|
|
/*
|
|
* Collect ssid's that need to be disabled from default
|
|
* hierarchy.
|
|
*/
|
|
if (ss->root == &cgrp_dfl_root)
|
|
dfl_disable_ss_mask |= 1 << ssid;
|
|
|
|
} while_each_subsys_mask();
|
|
|
|
if (dfl_disable_ss_mask) {
|
|
struct cgroup *scgrp = &cgrp_dfl_root.cgrp;
|
|
|
|
/*
|
|
* Controllers from default hierarchy that need to be rebound
|
|
* are all disabled together in one go.
|
|
*/
|
|
cgrp_dfl_root.subsys_mask &= ~dfl_disable_ss_mask;
|
|
WARN_ON(cgroup_apply_control(scgrp));
|
|
cgroup_finalize_control(scgrp, 0);
|
|
}
|
|
|
|
do_each_subsys_mask(ss, ssid, ss_mask) {
|
|
struct cgroup_root *src_root = ss->root;
|
|
struct cgroup *scgrp = &src_root->cgrp;
|
|
struct cgroup_subsys_state *css = cgroup_css(scgrp, ss);
|
|
struct css_set *cset;
|
|
|
|
WARN_ON(!css || cgroup_css(dcgrp, ss));
|
|
|
|
if (src_root != &cgrp_dfl_root) {
|
|
/* disable from the source */
|
|
src_root->subsys_mask &= ~(1 << ssid);
|
|
WARN_ON(cgroup_apply_control(scgrp));
|
|
cgroup_finalize_control(scgrp, 0);
|
|
}
|
|
|
|
/* rebind */
|
|
RCU_INIT_POINTER(scgrp->subsys[ssid], NULL);
|
|
rcu_assign_pointer(dcgrp->subsys[ssid], css);
|
|
ss->root = dst_root;
|
|
css->cgroup = dcgrp;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
hash_for_each(css_set_table, i, cset, hlist)
|
|
list_move_tail(&cset->e_cset_node[ss->id],
|
|
&dcgrp->e_csets[ss->id]);
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/* default hierarchy doesn't enable controllers by default */
|
|
dst_root->subsys_mask |= 1 << ssid;
|
|
if (dst_root == &cgrp_dfl_root) {
|
|
static_branch_enable(cgroup_subsys_on_dfl_key[ssid]);
|
|
} else {
|
|
dcgrp->subtree_control |= 1 << ssid;
|
|
static_branch_disable(cgroup_subsys_on_dfl_key[ssid]);
|
|
}
|
|
|
|
ret = cgroup_apply_control(dcgrp);
|
|
if (ret)
|
|
pr_warn("partial failure to rebind %s controller (err=%d)\n",
|
|
ss->name, ret);
|
|
|
|
if (ss->bind)
|
|
ss->bind(css);
|
|
} while_each_subsys_mask();
|
|
|
|
kernfs_activate(dcgrp->kn);
|
|
return 0;
|
|
}
|
|
|
|
int cgroup_show_path(struct seq_file *sf, struct kernfs_node *kf_node,
|
|
struct kernfs_root *kf_root)
|
|
{
|
|
int len = 0;
|
|
char *buf = NULL;
|
|
struct cgroup_root *kf_cgroot = cgroup_root_from_kf(kf_root);
|
|
struct cgroup *ns_cgroup;
|
|
|
|
buf = kmalloc(PATH_MAX, GFP_KERNEL);
|
|
if (!buf)
|
|
return -ENOMEM;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
ns_cgroup = current_cgns_cgroup_from_root(kf_cgroot);
|
|
len = kernfs_path_from_node(kf_node, ns_cgroup->kn, buf, PATH_MAX);
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
if (len >= PATH_MAX)
|
|
len = -ERANGE;
|
|
else if (len > 0) {
|
|
seq_escape(sf, buf, " \t\n\\");
|
|
len = 0;
|
|
}
|
|
kfree(buf);
|
|
return len;
|
|
}
|
|
|
|
enum cgroup2_param {
|
|
Opt_nsdelegate,
|
|
Opt_memory_localevents,
|
|
nr__cgroup2_params
|
|
};
|
|
|
|
static const struct fs_parameter_spec cgroup2_param_specs[] = {
|
|
fsparam_flag("nsdelegate", Opt_nsdelegate),
|
|
fsparam_flag("memory_localevents", Opt_memory_localevents),
|
|
{}
|
|
};
|
|
|
|
static const struct fs_parameter_description cgroup2_fs_parameters = {
|
|
.name = "cgroup2",
|
|
.specs = cgroup2_param_specs,
|
|
};
|
|
|
|
static int cgroup2_parse_param(struct fs_context *fc, struct fs_parameter *param)
|
|
{
|
|
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
|
|
struct fs_parse_result result;
|
|
int opt;
|
|
|
|
opt = fs_parse(fc, &cgroup2_fs_parameters, param, &result);
|
|
if (opt < 0)
|
|
return opt;
|
|
|
|
switch (opt) {
|
|
case Opt_nsdelegate:
|
|
ctx->flags |= CGRP_ROOT_NS_DELEGATE;
|
|
return 0;
|
|
case Opt_memory_localevents:
|
|
ctx->flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;
|
|
return 0;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
static void apply_cgroup_root_flags(unsigned int root_flags)
|
|
{
|
|
if (current->nsproxy->cgroup_ns == &init_cgroup_ns) {
|
|
if (root_flags & CGRP_ROOT_NS_DELEGATE)
|
|
cgrp_dfl_root.flags |= CGRP_ROOT_NS_DELEGATE;
|
|
else
|
|
cgrp_dfl_root.flags &= ~CGRP_ROOT_NS_DELEGATE;
|
|
|
|
if (root_flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
|
|
cgrp_dfl_root.flags |= CGRP_ROOT_MEMORY_LOCAL_EVENTS;
|
|
else
|
|
cgrp_dfl_root.flags &= ~CGRP_ROOT_MEMORY_LOCAL_EVENTS;
|
|
}
|
|
}
|
|
|
|
static int cgroup_show_options(struct seq_file *seq, struct kernfs_root *kf_root)
|
|
{
|
|
if (cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE)
|
|
seq_puts(seq, ",nsdelegate");
|
|
if (cgrp_dfl_root.flags & CGRP_ROOT_MEMORY_LOCAL_EVENTS)
|
|
seq_puts(seq, ",memory_localevents");
|
|
return 0;
|
|
}
|
|
|
|
static int cgroup_reconfigure(struct fs_context *fc)
|
|
{
|
|
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
|
|
|
|
apply_cgroup_root_flags(ctx->flags);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* To reduce the fork() overhead for systems that are not actually using
|
|
* their cgroups capability, we don't maintain the lists running through
|
|
* each css_set to its tasks until we see the list actually used - in other
|
|
* words after the first mount.
|
|
*/
|
|
static bool use_task_css_set_links __read_mostly;
|
|
|
|
#ifdef CONFIG_MEM_QOS
|
|
static void css_account_procs(struct task_struct *task, struct css_set *cset,
|
|
int num)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
if (!thread_group_leader(task))
|
|
return;
|
|
|
|
for_each_subsys(ss, ssid) {
|
|
struct cgroup_subsys_state *css = cset->subsys[ssid];
|
|
|
|
if (!css)
|
|
continue;
|
|
css->nr_procs += num;
|
|
while (css->parent) {
|
|
css = css->parent;
|
|
css->nr_procs += num;
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
static void do_css_account_procs(struct task_struct *task, struct css_set *cset,
|
|
int num)
|
|
{
|
|
#ifdef CONFIG_MEM_QOS
|
|
css_account_procs(task, cset, num);
|
|
#endif
|
|
}
|
|
|
|
void cgroup_enable_task_cg_lists(void)
|
|
{
|
|
struct task_struct *p, *g;
|
|
|
|
/*
|
|
* We need tasklist_lock because RCU is not safe against
|
|
* while_each_thread(). Besides, a forking task that has passed
|
|
* cgroup_post_fork() without seeing use_task_css_set_links = 1
|
|
* is not guaranteed to have its child immediately visible in the
|
|
* tasklist if we walk through it with RCU.
|
|
*/
|
|
read_lock(&tasklist_lock);
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
if (use_task_css_set_links)
|
|
goto out_unlock;
|
|
|
|
use_task_css_set_links = true;
|
|
|
|
do_each_thread(g, p) {
|
|
WARN_ON_ONCE(!list_empty(&p->cg_list) ||
|
|
task_css_set(p) != &init_css_set);
|
|
|
|
/*
|
|
* We should check if the process is exiting, otherwise
|
|
* it will race with cgroup_exit() in that the list
|
|
* entry won't be deleted though the process has exited.
|
|
* Do it while holding siglock so that we don't end up
|
|
* racing against cgroup_exit().
|
|
*
|
|
* Interrupts were already disabled while acquiring
|
|
* the css_set_lock, so we do not need to disable it
|
|
* again when acquiring the sighand->siglock here.
|
|
*/
|
|
spin_lock(&p->sighand->siglock);
|
|
if (!(p->flags & PF_EXITING)) {
|
|
struct css_set *cset = task_css_set(p);
|
|
|
|
if (!css_set_populated(cset))
|
|
css_set_update_populated(cset, true);
|
|
list_add_tail(&p->cg_list, &cset->tasks);
|
|
get_css_set(cset);
|
|
cset->nr_tasks++;
|
|
do_css_account_procs(p, cset, 1);
|
|
}
|
|
spin_unlock(&p->sighand->siglock);
|
|
} while_each_thread(g, p);
|
|
out_unlock:
|
|
spin_unlock_irq(&css_set_lock);
|
|
read_unlock(&tasklist_lock);
|
|
}
|
|
|
|
static void init_cgroup_housekeeping(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
INIT_LIST_HEAD(&cgrp->self.sibling);
|
|
INIT_LIST_HEAD(&cgrp->self.children);
|
|
INIT_LIST_HEAD(&cgrp->cset_links);
|
|
INIT_LIST_HEAD(&cgrp->pidlists);
|
|
mutex_init(&cgrp->pidlist_mutex);
|
|
cgrp->self.cgroup = cgrp;
|
|
cgrp->self.flags |= CSS_ONLINE;
|
|
cgrp->dom_cgrp = cgrp;
|
|
cgrp->max_descendants = INT_MAX;
|
|
cgrp->max_depth = INT_MAX;
|
|
cgrp->priority = 0;
|
|
INIT_LIST_HEAD(&cgrp->rstat_css_list);
|
|
prev_cputime_init(&cgrp->prev_cputime);
|
|
|
|
for_each_subsys(ss, ssid)
|
|
INIT_LIST_HEAD(&cgrp->e_csets[ssid]);
|
|
|
|
init_waitqueue_head(&cgrp->offline_waitq);
|
|
INIT_WORK(&cgrp->release_agent_work, cgroup1_release_agent);
|
|
}
|
|
|
|
void init_cgroup_root(struct cgroup_fs_context *ctx)
|
|
{
|
|
struct cgroup_root *root = ctx->root;
|
|
struct cgroup *cgrp = &root->cgrp;
|
|
|
|
INIT_LIST_HEAD(&root->root_list);
|
|
atomic_set(&root->nr_cgrps, 1);
|
|
cgrp->root = root;
|
|
init_cgroup_housekeeping(cgrp);
|
|
idr_init(&root->cgroup_idr);
|
|
|
|
root->flags = ctx->flags;
|
|
if (ctx->release_agent)
|
|
strscpy(root->release_agent_path, ctx->release_agent, PATH_MAX);
|
|
if (ctx->name)
|
|
strscpy(root->name, ctx->name, MAX_CGROUP_ROOT_NAMELEN);
|
|
if (ctx->cpuset_clone_children)
|
|
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &root->cgrp.flags);
|
|
}
|
|
|
|
int cgroup_setup_root(struct cgroup_root *root, u16 ss_mask)
|
|
{
|
|
LIST_HEAD(tmp_links);
|
|
struct cgroup *root_cgrp = &root->cgrp;
|
|
struct kernfs_syscall_ops *kf_sops;
|
|
struct css_set *cset;
|
|
int i, ret;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
ret = cgroup_idr_alloc(&root->cgroup_idr, root_cgrp, 1, 2, GFP_KERNEL);
|
|
if (ret < 0)
|
|
goto out;
|
|
root_cgrp->id = ret;
|
|
root_cgrp->ancestor_ids[0] = ret;
|
|
|
|
ret = percpu_ref_init(&root_cgrp->self.refcnt, css_release,
|
|
0, GFP_KERNEL);
|
|
if (ret)
|
|
goto out;
|
|
|
|
/*
|
|
* We're accessing css_set_count without locking css_set_lock here,
|
|
* but that's OK - it can only be increased by someone holding
|
|
* cgroup_lock, and that's us. Later rebinding may disable
|
|
* controllers on the default hierarchy and thus create new csets,
|
|
* which can't be more than the existing ones. Allocate 2x.
|
|
*/
|
|
ret = allocate_cgrp_cset_links(2 * css_set_count, &tmp_links);
|
|
if (ret)
|
|
goto cancel_ref;
|
|
|
|
ret = cgroup_init_root_id(root);
|
|
if (ret)
|
|
goto cancel_ref;
|
|
|
|
kf_sops = root == &cgrp_dfl_root ?
|
|
&cgroup_kf_syscall_ops : &cgroup1_kf_syscall_ops;
|
|
|
|
root->kf_root = kernfs_create_root(kf_sops,
|
|
KERNFS_ROOT_CREATE_DEACTIVATED |
|
|
KERNFS_ROOT_SUPPORT_EXPORTOP,
|
|
root_cgrp);
|
|
if (IS_ERR(root->kf_root)) {
|
|
ret = PTR_ERR(root->kf_root);
|
|
goto exit_root_id;
|
|
}
|
|
root_cgrp->kn = root->kf_root->kn;
|
|
|
|
ret = css_populate_dir(&root_cgrp->self);
|
|
if (ret)
|
|
goto destroy_root;
|
|
|
|
ret = rebind_subsystems(root, ss_mask);
|
|
if (ret)
|
|
goto destroy_root;
|
|
|
|
ret = cgroup_bpf_inherit(root_cgrp);
|
|
WARN_ON_ONCE(ret);
|
|
|
|
trace_cgroup_setup_root(root);
|
|
|
|
/*
|
|
* There must be no failure case after here, since rebinding takes
|
|
* care of subsystems' refcounts, which are explicitly dropped in
|
|
* the failure exit path.
|
|
*/
|
|
list_add(&root->root_list, &cgroup_roots);
|
|
cgroup_root_count++;
|
|
|
|
/*
|
|
* Link the root cgroup in this hierarchy into all the css_set
|
|
* objects.
|
|
*/
|
|
spin_lock_irq(&css_set_lock);
|
|
hash_for_each(css_set_table, i, cset, hlist) {
|
|
link_css_set(&tmp_links, cset, root_cgrp);
|
|
if (css_set_populated(cset))
|
|
cgroup_update_populated(root_cgrp, true);
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
BUG_ON(!list_empty(&root_cgrp->self.children));
|
|
BUG_ON(atomic_read(&root->nr_cgrps) != 1);
|
|
|
|
kernfs_activate(root_cgrp->kn);
|
|
ret = 0;
|
|
goto out;
|
|
|
|
destroy_root:
|
|
kernfs_destroy_root(root->kf_root);
|
|
root->kf_root = NULL;
|
|
exit_root_id:
|
|
cgroup_exit_root_id(root);
|
|
cancel_ref:
|
|
percpu_ref_exit(&root_cgrp->self.refcnt);
|
|
out:
|
|
free_cgrp_cset_links(&tmp_links);
|
|
return ret;
|
|
}
|
|
|
|
int cgroup_do_get_tree(struct fs_context *fc)
|
|
{
|
|
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
|
|
int ret;
|
|
|
|
ctx->kfc.root = ctx->root->kf_root;
|
|
if (fc->fs_type == &cgroup2_fs_type)
|
|
ctx->kfc.magic = CGROUP2_SUPER_MAGIC;
|
|
else
|
|
ctx->kfc.magic = CGROUP_SUPER_MAGIC;
|
|
ret = kernfs_get_tree(fc);
|
|
|
|
/*
|
|
* In non-init cgroup namespace, instead of root cgroup's dentry,
|
|
* we return the dentry corresponding to the cgroupns->root_cgrp.
|
|
*/
|
|
if (!ret && ctx->ns != &init_cgroup_ns) {
|
|
struct dentry *nsdentry;
|
|
struct super_block *sb = fc->root->d_sb;
|
|
struct cgroup *cgrp;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
cgrp = cset_cgroup_from_root(ctx->ns->root_cset, ctx->root);
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
mutex_unlock(&cgroup_mutex);
|
|
|
|
nsdentry = kernfs_node_dentry(cgrp->kn, sb);
|
|
dput(fc->root);
|
|
if (IS_ERR(nsdentry)) {
|
|
deactivate_locked_super(sb);
|
|
ret = PTR_ERR(nsdentry);
|
|
nsdentry = NULL;
|
|
}
|
|
fc->root = nsdentry;
|
|
}
|
|
|
|
if (!ctx->kfc.new_sb_created)
|
|
cgroup_put(&ctx->root->cgrp);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Destroy a cgroup filesystem context.
|
|
*/
|
|
static void cgroup_fs_context_free(struct fs_context *fc)
|
|
{
|
|
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
|
|
|
|
kfree(ctx->name);
|
|
kfree(ctx->release_agent);
|
|
put_cgroup_ns(ctx->ns);
|
|
kernfs_free_fs_context(fc);
|
|
kfree(ctx);
|
|
}
|
|
|
|
static int cgroup_get_tree(struct fs_context *fc)
|
|
{
|
|
struct cgroup_fs_context *ctx = cgroup_fc2context(fc);
|
|
int ret;
|
|
|
|
cgrp_dfl_visible = true;
|
|
cgroup_get_live(&cgrp_dfl_root.cgrp);
|
|
ctx->root = &cgrp_dfl_root;
|
|
|
|
ret = cgroup_do_get_tree(fc);
|
|
if (!ret)
|
|
apply_cgroup_root_flags(ctx->flags);
|
|
return ret;
|
|
}
|
|
|
|
static const struct fs_context_operations cgroup_fs_context_ops = {
|
|
.free = cgroup_fs_context_free,
|
|
.parse_param = cgroup2_parse_param,
|
|
.get_tree = cgroup_get_tree,
|
|
.reconfigure = cgroup_reconfigure,
|
|
};
|
|
|
|
static const struct fs_context_operations cgroup1_fs_context_ops = {
|
|
.free = cgroup_fs_context_free,
|
|
.parse_param = cgroup1_parse_param,
|
|
.get_tree = cgroup1_get_tree,
|
|
.reconfigure = cgroup1_reconfigure,
|
|
};
|
|
|
|
/*
|
|
* Initialise the cgroup filesystem creation/reconfiguration context. Notably,
|
|
* we select the namespace we're going to use.
|
|
*/
|
|
static int cgroup_init_fs_context(struct fs_context *fc)
|
|
{
|
|
struct cgroup_fs_context *ctx;
|
|
|
|
ctx = kzalloc(sizeof(struct cgroup_fs_context), GFP_KERNEL);
|
|
if (!ctx)
|
|
return -ENOMEM;
|
|
|
|
/*
|
|
* The first time anyone tries to mount a cgroup, enable the list
|
|
* linking each css_set to its tasks and fix up all existing tasks.
|
|
*/
|
|
if (!use_task_css_set_links)
|
|
cgroup_enable_task_cg_lists();
|
|
|
|
ctx->ns = current->nsproxy->cgroup_ns;
|
|
get_cgroup_ns(ctx->ns);
|
|
fc->fs_private = &ctx->kfc;
|
|
if (fc->fs_type == &cgroup2_fs_type)
|
|
fc->ops = &cgroup_fs_context_ops;
|
|
else
|
|
fc->ops = &cgroup1_fs_context_ops;
|
|
put_user_ns(fc->user_ns);
|
|
fc->user_ns = get_user_ns(ctx->ns->user_ns);
|
|
fc->global = true;
|
|
return 0;
|
|
}
|
|
|
|
static void cgroup_kill_sb(struct super_block *sb)
|
|
{
|
|
struct kernfs_root *kf_root = kernfs_root_from_sb(sb);
|
|
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
|
|
|
|
/*
|
|
* If @root doesn't have any children, start killing it.
|
|
* This prevents new mounts by disabling percpu_ref_tryget_live().
|
|
* cgroup_mount() may wait for @root's release.
|
|
*
|
|
* And don't kill the default root.
|
|
*/
|
|
if (list_empty(&root->cgrp.self.children) && root != &cgrp_dfl_root &&
|
|
!percpu_ref_is_dying(&root->cgrp.self.refcnt))
|
|
percpu_ref_kill(&root->cgrp.self.refcnt);
|
|
cgroup_put(&root->cgrp);
|
|
kernfs_kill_sb(sb);
|
|
}
|
|
|
|
struct file_system_type cgroup_fs_type = {
|
|
.name = "cgroup",
|
|
.init_fs_context = cgroup_init_fs_context,
|
|
.parameters = &cgroup1_fs_parameters,
|
|
.kill_sb = cgroup_kill_sb,
|
|
.fs_flags = FS_USERNS_MOUNT,
|
|
};
|
|
|
|
static struct file_system_type cgroup2_fs_type = {
|
|
.name = "cgroup2",
|
|
.init_fs_context = cgroup_init_fs_context,
|
|
.parameters = &cgroup2_fs_parameters,
|
|
.kill_sb = cgroup_kill_sb,
|
|
.fs_flags = FS_USERNS_MOUNT,
|
|
};
|
|
|
|
#ifdef CONFIG_CPUSETS
|
|
static const struct fs_context_operations cpuset_fs_context_ops = {
|
|
.get_tree = cgroup1_get_tree,
|
|
.free = cgroup_fs_context_free,
|
|
};
|
|
|
|
/*
|
|
* This is ugly, but preserves the userspace API for existing cpuset
|
|
* users. If someone tries to mount the "cpuset" filesystem, we
|
|
* silently switch it to mount "cgroup" instead
|
|
*/
|
|
static int cpuset_init_fs_context(struct fs_context *fc)
|
|
{
|
|
char *agent = kstrdup("/sbin/cpuset_release_agent", GFP_USER);
|
|
struct cgroup_fs_context *ctx;
|
|
int err;
|
|
|
|
err = cgroup_init_fs_context(fc);
|
|
if (err) {
|
|
kfree(agent);
|
|
return err;
|
|
}
|
|
|
|
fc->ops = &cpuset_fs_context_ops;
|
|
|
|
ctx = cgroup_fc2context(fc);
|
|
ctx->subsys_mask = 1 << cpuset_cgrp_id;
|
|
ctx->flags |= CGRP_ROOT_NOPREFIX;
|
|
ctx->release_agent = agent;
|
|
|
|
get_filesystem(&cgroup_fs_type);
|
|
put_filesystem(fc->fs_type);
|
|
fc->fs_type = &cgroup_fs_type;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct file_system_type cpuset_fs_type = {
|
|
.name = "cpuset",
|
|
.init_fs_context = cpuset_init_fs_context,
|
|
.fs_flags = FS_USERNS_MOUNT,
|
|
};
|
|
#endif
|
|
|
|
int cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
|
|
struct cgroup_namespace *ns)
|
|
{
|
|
struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
|
|
|
|
return kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
|
|
}
|
|
|
|
int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
|
|
struct cgroup_namespace *ns)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
mutex_unlock(&cgroup_mutex);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cgroup_path_ns);
|
|
|
|
/**
|
|
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
|
|
* @task: target task
|
|
* @buf: the buffer to write the path into
|
|
* @buflen: the length of the buffer
|
|
*
|
|
* Determine @task's cgroup on the first (the one with the lowest non-zero
|
|
* hierarchy_id) cgroup hierarchy and copy its path into @buf. This
|
|
* function grabs cgroup_mutex and shouldn't be used inside locks used by
|
|
* cgroup controller callbacks.
|
|
*
|
|
* Return value is the same as kernfs_path().
|
|
*/
|
|
int task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
|
|
{
|
|
struct cgroup_root *root;
|
|
struct cgroup *cgrp;
|
|
int hierarchy_id = 1;
|
|
int ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
root = idr_get_next(&cgroup_hierarchy_idr, &hierarchy_id);
|
|
|
|
if (root) {
|
|
cgrp = task_cgroup_from_root(task, root);
|
|
ret = cgroup_path_ns_locked(cgrp, buf, buflen, &init_cgroup_ns);
|
|
} else {
|
|
/* if no hierarchy exists, everyone is in "/" */
|
|
ret = strlcpy(buf, "/", buflen);
|
|
}
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
mutex_unlock(&cgroup_mutex);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(task_cgroup_path);
|
|
|
|
/**
|
|
* cgroup_attach_lock - Lock for ->attach()
|
|
* @lock_threadgroup: whether to down_write cgroup_threadgroup_rwsem
|
|
*
|
|
* cgroup migration sometimes needs to stabilize threadgroups against forks and
|
|
* exits by write-locking cgroup_threadgroup_rwsem. However, some ->attach()
|
|
* implementations (e.g. cpuset), also need to disable CPU hotplug.
|
|
* Unfortunately, letting ->attach() operations acquire cpus_read_lock() can
|
|
* lead to deadlocks.
|
|
*
|
|
* Bringing up a CPU may involve creating and destroying tasks which requires
|
|
* read-locking threadgroup_rwsem, so threadgroup_rwsem nests inside
|
|
* cpus_read_lock(). If we call an ->attach() which acquires the cpus lock while
|
|
* write-locking threadgroup_rwsem, the locking order is reversed and we end up
|
|
* waiting for an on-going CPU hotplug operation which in turn is waiting for
|
|
* the threadgroup_rwsem to be released to create new tasks. For more details:
|
|
*
|
|
* http://lkml.kernel.org/r/20220711174629.uehfmqegcwn2lqzu@wubuntu
|
|
*
|
|
* Resolve the situation by always acquiring cpus_read_lock() before optionally
|
|
* write-locking cgroup_threadgroup_rwsem. This allows ->attach() to assume that
|
|
* CPU hotplug is disabled on entry.
|
|
*/
|
|
static void cgroup_attach_lock(bool lock_threadgroup)
|
|
{
|
|
cpus_read_lock();
|
|
if (lock_threadgroup)
|
|
percpu_down_write(&cgroup_threadgroup_rwsem);
|
|
}
|
|
|
|
/**
|
|
* cgroup_attach_unlock - Undo cgroup_attach_lock()
|
|
* @lock_threadgroup: whether to up_write cgroup_threadgroup_rwsem
|
|
*/
|
|
static void cgroup_attach_unlock(bool lock_threadgroup)
|
|
{
|
|
if (lock_threadgroup)
|
|
percpu_up_write(&cgroup_threadgroup_rwsem);
|
|
cpus_read_unlock();
|
|
}
|
|
|
|
/**
|
|
* cgroup_migrate_add_task - add a migration target task to a migration context
|
|
* @task: target task
|
|
* @mgctx: target migration context
|
|
*
|
|
* Add @task, which is a migration target, to @mgctx->tset. This function
|
|
* becomes noop if @task doesn't need to be migrated. @task's css_set
|
|
* should have been added as a migration source and @task->cg_list will be
|
|
* moved from the css_set's tasks list to mg_tasks one.
|
|
*/
|
|
static void cgroup_migrate_add_task(struct task_struct *task,
|
|
struct cgroup_mgctx *mgctx)
|
|
{
|
|
struct css_set *cset;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
/* @task either already exited or can't exit until the end */
|
|
if (task->flags & PF_EXITING)
|
|
return;
|
|
|
|
/* leave @task alone if post_fork() hasn't linked it yet */
|
|
if (list_empty(&task->cg_list))
|
|
return;
|
|
|
|
cset = task_css_set(task);
|
|
if (!cset->mg_src_cgrp)
|
|
return;
|
|
|
|
mgctx->tset.nr_tasks++;
|
|
|
|
list_move_tail(&task->cg_list, &cset->mg_tasks);
|
|
if (list_empty(&cset->mg_node))
|
|
list_add_tail(&cset->mg_node,
|
|
&mgctx->tset.src_csets);
|
|
if (list_empty(&cset->mg_dst_cset->mg_node))
|
|
list_add_tail(&cset->mg_dst_cset->mg_node,
|
|
&mgctx->tset.dst_csets);
|
|
}
|
|
|
|
/**
|
|
* cgroup_taskset_first - reset taskset and return the first task
|
|
* @tset: taskset of interest
|
|
* @dst_cssp: output variable for the destination css
|
|
*
|
|
* @tset iteration is initialized and the first task is returned.
|
|
*/
|
|
struct task_struct *cgroup_taskset_first(struct cgroup_taskset *tset,
|
|
struct cgroup_subsys_state **dst_cssp)
|
|
{
|
|
tset->cur_cset = list_first_entry(tset->csets, struct css_set, mg_node);
|
|
tset->cur_task = NULL;
|
|
|
|
return cgroup_taskset_next(tset, dst_cssp);
|
|
}
|
|
|
|
/**
|
|
* cgroup_taskset_next - iterate to the next task in taskset
|
|
* @tset: taskset of interest
|
|
* @dst_cssp: output variable for the destination css
|
|
*
|
|
* Return the next task in @tset. Iteration must have been initialized
|
|
* with cgroup_taskset_first().
|
|
*/
|
|
struct task_struct *cgroup_taskset_next(struct cgroup_taskset *tset,
|
|
struct cgroup_subsys_state **dst_cssp)
|
|
{
|
|
struct css_set *cset = tset->cur_cset;
|
|
struct task_struct *task = tset->cur_task;
|
|
|
|
while (&cset->mg_node != tset->csets) {
|
|
if (!task)
|
|
task = list_first_entry(&cset->mg_tasks,
|
|
struct task_struct, cg_list);
|
|
else
|
|
task = list_next_entry(task, cg_list);
|
|
|
|
if (&task->cg_list != &cset->mg_tasks) {
|
|
tset->cur_cset = cset;
|
|
tset->cur_task = task;
|
|
|
|
/*
|
|
* This function may be called both before and
|
|
* after cgroup_taskset_migrate(). The two cases
|
|
* can be distinguished by looking at whether @cset
|
|
* has its ->mg_dst_cset set.
|
|
*/
|
|
if (cset->mg_dst_cset)
|
|
*dst_cssp = cset->mg_dst_cset->subsys[tset->ssid];
|
|
else
|
|
*dst_cssp = cset->subsys[tset->ssid];
|
|
|
|
return task;
|
|
}
|
|
|
|
cset = list_next_entry(cset, mg_node);
|
|
task = NULL;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* cgroup_taskset_migrate - migrate a taskset
|
|
* @mgctx: migration context
|
|
*
|
|
* Migrate tasks in @mgctx as setup by migration preparation functions.
|
|
* This function fails iff one of the ->can_attach callbacks fails and
|
|
* guarantees that either all or none of the tasks in @mgctx are migrated.
|
|
* @mgctx is consumed regardless of success.
|
|
*/
|
|
static int cgroup_migrate_execute(struct cgroup_mgctx *mgctx)
|
|
{
|
|
struct cgroup_taskset *tset = &mgctx->tset;
|
|
struct cgroup_subsys *ss;
|
|
struct task_struct *task, *tmp_task;
|
|
struct css_set *cset, *tmp_cset;
|
|
int ssid, failed_ssid, ret;
|
|
|
|
/* check that we can legitimately attach to the cgroup */
|
|
if (tset->nr_tasks) {
|
|
do_each_subsys_mask(ss, ssid, mgctx->ss_mask) {
|
|
if (ss->can_attach) {
|
|
tset->ssid = ssid;
|
|
ret = ss->can_attach(tset);
|
|
if (ret) {
|
|
failed_ssid = ssid;
|
|
goto out_cancel_attach;
|
|
}
|
|
}
|
|
} while_each_subsys_mask();
|
|
}
|
|
|
|
/*
|
|
* Now that we're guaranteed success, proceed to move all tasks to
|
|
* the new cgroup. There are no failure cases after here, so this
|
|
* is the commit point.
|
|
*/
|
|
spin_lock_irq(&css_set_lock);
|
|
list_for_each_entry(cset, &tset->src_csets, mg_node) {
|
|
list_for_each_entry_safe(task, tmp_task, &cset->mg_tasks, cg_list) {
|
|
struct css_set *from_cset = task_css_set(task);
|
|
struct css_set *to_cset = cset->mg_dst_cset;
|
|
|
|
get_css_set(to_cset);
|
|
to_cset->nr_tasks++;
|
|
do_css_account_procs(task, to_cset, 1);
|
|
css_set_move_task(task, from_cset, to_cset, true);
|
|
from_cset->nr_tasks--;
|
|
do_css_account_procs(task, from_cset, -1);
|
|
/*
|
|
* If the source or destination cgroup is frozen,
|
|
* the task might require to change its state.
|
|
*/
|
|
cgroup_freezer_migrate_task(task, from_cset->dfl_cgrp,
|
|
to_cset->dfl_cgrp);
|
|
put_css_set_locked(from_cset);
|
|
|
|
}
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/*
|
|
* Migration is committed, all target tasks are now on dst_csets.
|
|
* Nothing is sensitive to fork() after this point. Notify
|
|
* controllers that migration is complete.
|
|
*/
|
|
tset->csets = &tset->dst_csets;
|
|
|
|
if (tset->nr_tasks) {
|
|
do_each_subsys_mask(ss, ssid, mgctx->ss_mask) {
|
|
if (ss->attach) {
|
|
tset->ssid = ssid;
|
|
ss->attach(tset);
|
|
}
|
|
} while_each_subsys_mask();
|
|
}
|
|
|
|
ret = 0;
|
|
goto out_release_tset;
|
|
|
|
out_cancel_attach:
|
|
if (tset->nr_tasks) {
|
|
do_each_subsys_mask(ss, ssid, mgctx->ss_mask) {
|
|
if (ssid == failed_ssid)
|
|
break;
|
|
if (ss->cancel_attach) {
|
|
tset->ssid = ssid;
|
|
ss->cancel_attach(tset);
|
|
}
|
|
} while_each_subsys_mask();
|
|
}
|
|
out_release_tset:
|
|
spin_lock_irq(&css_set_lock);
|
|
list_splice_init(&tset->dst_csets, &tset->src_csets);
|
|
list_for_each_entry_safe(cset, tmp_cset, &tset->src_csets, mg_node) {
|
|
list_splice_tail_init(&cset->mg_tasks, &cset->tasks);
|
|
list_del_init(&cset->mg_node);
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/*
|
|
* Re-initialize the cgroup_taskset structure in case it is reused
|
|
* again in another cgroup_migrate_add_task()/cgroup_migrate_execute()
|
|
* iteration.
|
|
*/
|
|
tset->nr_tasks = 0;
|
|
tset->csets = &tset->src_csets;
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cgroup_migrate_vet_dst - verify whether a cgroup can be migration destination
|
|
* @dst_cgrp: destination cgroup to test
|
|
*
|
|
* On the default hierarchy, except for the mixable, (possible) thread root
|
|
* and threaded cgroups, subtree_control must be zero for migration
|
|
* destination cgroups with tasks so that child cgroups don't compete
|
|
* against tasks.
|
|
*/
|
|
int cgroup_migrate_vet_dst(struct cgroup *dst_cgrp)
|
|
{
|
|
/* v1 doesn't have any restriction */
|
|
if (!cgroup_on_dfl(dst_cgrp))
|
|
return 0;
|
|
|
|
/* verify @dst_cgrp can host resources */
|
|
if (!cgroup_is_valid_domain(dst_cgrp->dom_cgrp))
|
|
return -EOPNOTSUPP;
|
|
|
|
/* mixables don't care */
|
|
if (cgroup_is_mixable(dst_cgrp))
|
|
return 0;
|
|
|
|
/*
|
|
* If @dst_cgrp is already or can become a thread root or is
|
|
* threaded, it doesn't matter.
|
|
*/
|
|
if (cgroup_can_be_thread_root(dst_cgrp) || cgroup_is_threaded(dst_cgrp))
|
|
return 0;
|
|
|
|
/* apply no-internal-process constraint */
|
|
if (dst_cgrp->subtree_control)
|
|
return -EBUSY;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_migrate_finish - cleanup after attach
|
|
* @mgctx: migration context
|
|
*
|
|
* Undo cgroup_migrate_add_src() and cgroup_migrate_prepare_dst(). See
|
|
* those functions for details.
|
|
*/
|
|
void cgroup_migrate_finish(struct cgroup_mgctx *mgctx)
|
|
{
|
|
struct css_set *cset, *tmp_cset;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_src_csets,
|
|
mg_src_preload_node) {
|
|
cset->mg_src_cgrp = NULL;
|
|
cset->mg_dst_cgrp = NULL;
|
|
cset->mg_dst_cset = NULL;
|
|
list_del_init(&cset->mg_src_preload_node);
|
|
put_css_set_locked(cset);
|
|
}
|
|
|
|
list_for_each_entry_safe(cset, tmp_cset, &mgctx->preloaded_dst_csets,
|
|
mg_dst_preload_node) {
|
|
cset->mg_src_cgrp = NULL;
|
|
cset->mg_dst_cgrp = NULL;
|
|
cset->mg_dst_cset = NULL;
|
|
list_del_init(&cset->mg_dst_preload_node);
|
|
put_css_set_locked(cset);
|
|
}
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
}
|
|
|
|
/**
|
|
* cgroup_migrate_add_src - add a migration source css_set
|
|
* @src_cset: the source css_set to add
|
|
* @dst_cgrp: the destination cgroup
|
|
* @mgctx: migration context
|
|
*
|
|
* Tasks belonging to @src_cset are about to be migrated to @dst_cgrp. Pin
|
|
* @src_cset and add it to @mgctx->src_csets, which should later be cleaned
|
|
* up by cgroup_migrate_finish().
|
|
*
|
|
* This function may be called without holding cgroup_threadgroup_rwsem
|
|
* even if the target is a process. Threads may be created and destroyed
|
|
* but as long as cgroup_mutex is not dropped, no new css_set can be put
|
|
* into play and the preloaded css_sets are guaranteed to cover all
|
|
* migrations.
|
|
*/
|
|
void cgroup_migrate_add_src(struct css_set *src_cset,
|
|
struct cgroup *dst_cgrp,
|
|
struct cgroup_mgctx *mgctx)
|
|
{
|
|
struct cgroup *src_cgrp;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
/*
|
|
* If ->dead, @src_set is associated with one or more dead cgroups
|
|
* and doesn't contain any migratable tasks. Ignore it early so
|
|
* that the rest of migration path doesn't get confused by it.
|
|
*/
|
|
if (src_cset->dead)
|
|
return;
|
|
|
|
src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);
|
|
|
|
if (!list_empty(&src_cset->mg_src_preload_node))
|
|
return;
|
|
|
|
WARN_ON(src_cset->mg_src_cgrp);
|
|
WARN_ON(src_cset->mg_dst_cgrp);
|
|
WARN_ON(!list_empty(&src_cset->mg_tasks));
|
|
WARN_ON(!list_empty(&src_cset->mg_node));
|
|
|
|
src_cset->mg_src_cgrp = src_cgrp;
|
|
src_cset->mg_dst_cgrp = dst_cgrp;
|
|
get_css_set(src_cset);
|
|
list_add_tail(&src_cset->mg_src_preload_node, &mgctx->preloaded_src_csets);
|
|
}
|
|
|
|
/**
|
|
* cgroup_migrate_prepare_dst - prepare destination css_sets for migration
|
|
* @mgctx: migration context
|
|
*
|
|
* Tasks are about to be moved and all the source css_sets have been
|
|
* preloaded to @mgctx->preloaded_src_csets. This function looks up and
|
|
* pins all destination css_sets, links each to its source, and append them
|
|
* to @mgctx->preloaded_dst_csets.
|
|
*
|
|
* This function must be called after cgroup_migrate_add_src() has been
|
|
* called on each migration source css_set. After migration is performed
|
|
* using cgroup_migrate(), cgroup_migrate_finish() must be called on
|
|
* @mgctx.
|
|
*/
|
|
#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
|
|
unsigned int sysctl_allow_memcg_migrate_ignore_blkio_bind;
|
|
#endif
|
|
|
|
int cgroup_migrate_prepare_dst(struct cgroup_mgctx *mgctx)
|
|
{
|
|
struct css_set *src_cset, *tmp_cset;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/* look up the dst cset for each src cset and link it to src */
|
|
list_for_each_entry_safe(src_cset, tmp_cset, &mgctx->preloaded_src_csets,
|
|
mg_src_preload_node) {
|
|
struct css_set *dst_cset;
|
|
struct cgroup_subsys *ss;
|
|
#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
|
|
struct cgroup_subsys_state *css;
|
|
#endif
|
|
int ssid;
|
|
|
|
dst_cset = find_css_set(src_cset, src_cset->mg_dst_cgrp);
|
|
if (!dst_cset)
|
|
return -ENOMEM;
|
|
|
|
WARN_ON_ONCE(src_cset->mg_dst_cset || dst_cset->mg_dst_cset);
|
|
|
|
#if defined(CONFIG_MEMCG) && defined(CONFIG_BLK_CGROUP)
|
|
css = dst_cset->subsys[memory_cgrp_id];
|
|
if (!sysctl_allow_memcg_migrate_ignore_blkio_bind && css) {
|
|
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
|
|
|
|
css = dst_cset->subsys[io_cgrp_id];
|
|
if (css && memcg->bind_blkio && css != blkcg_root_css &&
|
|
memcg->bind_blkio != css) {
|
|
pr_err("memcg already bind blkio, disallow migrate");
|
|
return -EPERM;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* If src cset equals dst, it's noop. Drop the src.
|
|
* cgroup_migrate() will skip the cset too. Note that we
|
|
* can't handle src == dst as some nodes are used by both.
|
|
*/
|
|
if (src_cset == dst_cset) {
|
|
src_cset->mg_src_cgrp = NULL;
|
|
src_cset->mg_dst_cgrp = NULL;
|
|
list_del_init(&src_cset->mg_src_preload_node);
|
|
put_css_set(src_cset);
|
|
put_css_set(dst_cset);
|
|
continue;
|
|
}
|
|
|
|
src_cset->mg_dst_cset = dst_cset;
|
|
|
|
if (list_empty(&dst_cset->mg_dst_preload_node))
|
|
list_add_tail(&dst_cset->mg_dst_preload_node,
|
|
&mgctx->preloaded_dst_csets);
|
|
else
|
|
put_css_set(dst_cset);
|
|
|
|
for_each_subsys(ss, ssid)
|
|
if (src_cset->subsys[ssid] != dst_cset->subsys[ssid])
|
|
mgctx->ss_mask |= 1 << ssid;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_migrate - migrate a process or task to a cgroup
|
|
* @leader: the leader of the process or the task to migrate
|
|
* @threadgroup: whether @leader points to the whole process or a single task
|
|
* @mgctx: migration context
|
|
*
|
|
* Migrate a process or task denoted by @leader. If migrating a process,
|
|
* the caller must be holding cgroup_threadgroup_rwsem. The caller is also
|
|
* responsible for invoking cgroup_migrate_add_src() and
|
|
* cgroup_migrate_prepare_dst() on the targets before invoking this
|
|
* function and following up with cgroup_migrate_finish().
|
|
*
|
|
* As long as a controller's ->can_attach() doesn't fail, this function is
|
|
* guaranteed to succeed. This means that, excluding ->can_attach()
|
|
* failure, when migrating multiple targets, the success or failure can be
|
|
* decided for all targets by invoking group_migrate_prepare_dst() before
|
|
* actually starting migrating.
|
|
*/
|
|
int cgroup_migrate(struct task_struct *leader, bool threadgroup,
|
|
struct cgroup_mgctx *mgctx)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
/*
|
|
* Prevent freeing of tasks while we take a snapshot. Tasks that are
|
|
* already PF_EXITING could be freed from underneath us unless we
|
|
* take an rcu_read_lock.
|
|
*/
|
|
spin_lock_irq(&css_set_lock);
|
|
rcu_read_lock();
|
|
task = leader;
|
|
do {
|
|
cgroup_migrate_add_task(task, mgctx);
|
|
if (!threadgroup)
|
|
break;
|
|
} while_each_thread(leader, task);
|
|
rcu_read_unlock();
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
return cgroup_migrate_execute(mgctx);
|
|
}
|
|
|
|
/**
|
|
* cgroup_attach_task - attach a task or a whole threadgroup to a cgroup
|
|
* @dst_cgrp: the cgroup to attach to
|
|
* @leader: the task or the leader of the threadgroup to be attached
|
|
* @threadgroup: attach the whole threadgroup?
|
|
*
|
|
* Call holding cgroup_mutex and cgroup_threadgroup_rwsem.
|
|
*/
|
|
int cgroup_attach_task(struct cgroup *dst_cgrp, struct task_struct *leader,
|
|
bool threadgroup)
|
|
{
|
|
DEFINE_CGROUP_MGCTX(mgctx);
|
|
struct task_struct *task;
|
|
int ret;
|
|
|
|
ret = cgroup_migrate_vet_dst(dst_cgrp);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* look up all src csets */
|
|
spin_lock_irq(&css_set_lock);
|
|
rcu_read_lock();
|
|
task = leader;
|
|
do {
|
|
cgroup_migrate_add_src(task_css_set(task), dst_cgrp, &mgctx);
|
|
if (!threadgroup)
|
|
break;
|
|
} while_each_thread(leader, task);
|
|
rcu_read_unlock();
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/* prepare dst csets and commit */
|
|
ret = cgroup_migrate_prepare_dst(&mgctx);
|
|
if (!ret)
|
|
ret = cgroup_migrate(leader, threadgroup, &mgctx);
|
|
|
|
cgroup_migrate_finish(&mgctx);
|
|
|
|
if (!ret)
|
|
TRACE_CGROUP_PATH(attach_task, dst_cgrp, leader, threadgroup);
|
|
|
|
return ret;
|
|
}
|
|
|
|
struct task_struct *cgroup_procs_write_start(char *buf, bool threadgroup,
|
|
bool *threadgroup_locked)
|
|
{
|
|
struct task_struct *tsk;
|
|
pid_t pid;
|
|
|
|
if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0)
|
|
return ERR_PTR(-EINVAL);
|
|
|
|
/*
|
|
* If we migrate a single thread, we don't care about threadgroup
|
|
* stability. If the thread is `current`, it won't exit(2) under our
|
|
* hands or change PID through exec(2). We exclude
|
|
* cgroup_update_dfl_csses and other cgroup_{proc,thread}s_write
|
|
* callers by cgroup_mutex.
|
|
* Therefore, we can skip the global lock.
|
|
*/
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
*threadgroup_locked = pid || threadgroup;
|
|
cgroup_attach_lock(*threadgroup_locked);
|
|
|
|
rcu_read_lock();
|
|
if (pid) {
|
|
tsk = find_task_by_vpid(pid);
|
|
if (!tsk) {
|
|
tsk = ERR_PTR(-ESRCH);
|
|
goto out_unlock_threadgroup;
|
|
}
|
|
} else {
|
|
tsk = current;
|
|
}
|
|
|
|
if (threadgroup)
|
|
tsk = tsk->group_leader;
|
|
|
|
/*
|
|
* kthreads may acquire PF_NO_SETAFFINITY during initialization.
|
|
* If userland migrates such a kthread to a non-root cgroup, it can
|
|
* become trapped in a cpuset, or RT kthread may be born in a
|
|
* cgroup with no rt_runtime allocated. Just say no.
|
|
*/
|
|
if (tsk->no_cgroup_migration || (tsk->flags & PF_NO_SETAFFINITY)) {
|
|
tsk = ERR_PTR(-EINVAL);
|
|
goto out_unlock_threadgroup;
|
|
}
|
|
|
|
get_task_struct(tsk);
|
|
goto out_unlock_rcu;
|
|
|
|
out_unlock_threadgroup:
|
|
cgroup_attach_unlock(*threadgroup_locked);
|
|
*threadgroup_locked = false;
|
|
out_unlock_rcu:
|
|
rcu_read_unlock();
|
|
return tsk;
|
|
}
|
|
|
|
void cgroup_procs_write_finish(struct task_struct *task, bool threadgroup_locked)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
/* release reference from cgroup_procs_write_start() */
|
|
put_task_struct(task);
|
|
|
|
cgroup_attach_unlock(threadgroup_locked);
|
|
|
|
for_each_subsys(ss, ssid)
|
|
if (ss->post_attach)
|
|
ss->post_attach();
|
|
}
|
|
|
|
static void cgroup_print_ss_mask(struct seq_file *seq, u16 ss_mask)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
bool printed = false;
|
|
int ssid;
|
|
|
|
do_each_subsys_mask(ss, ssid, ss_mask) {
|
|
if (printed)
|
|
seq_putc(seq, ' ');
|
|
seq_puts(seq, ss->name);
|
|
printed = true;
|
|
} while_each_subsys_mask();
|
|
if (printed)
|
|
seq_putc(seq, '\n');
|
|
}
|
|
|
|
/* show controllers which are enabled from the parent */
|
|
static int cgroup_controllers_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
|
|
cgroup_print_ss_mask(seq, cgroup_control(cgrp));
|
|
return 0;
|
|
}
|
|
|
|
/* show controllers which are enabled for a given cgroup's children */
|
|
static int cgroup_subtree_control_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
|
|
cgroup_print_ss_mask(seq, cgrp->subtree_control);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_update_dfl_csses - update css assoc of a subtree in default hierarchy
|
|
* @cgrp: root of the subtree to update csses for
|
|
*
|
|
* @cgrp's control masks have changed and its subtree's css associations
|
|
* need to be updated accordingly. This function looks up all css_sets
|
|
* which are attached to the subtree, creates the matching updated css_sets
|
|
* and migrates the tasks to the new ones.
|
|
*/
|
|
static int cgroup_update_dfl_csses(struct cgroup *cgrp)
|
|
{
|
|
DEFINE_CGROUP_MGCTX(mgctx);
|
|
struct cgroup_subsys_state *d_css;
|
|
struct cgroup *dsct;
|
|
struct css_set *src_cset;
|
|
bool has_tasks;
|
|
int ret;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/* look up all csses currently attached to @cgrp's subtree */
|
|
spin_lock_irq(&css_set_lock);
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
|
|
struct cgrp_cset_link *link;
|
|
|
|
list_for_each_entry(link, &dsct->cset_links, cset_link)
|
|
cgroup_migrate_add_src(link->cset, dsct, &mgctx);
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/*
|
|
* We need to write-lock threadgroup_rwsem while migrating tasks.
|
|
* However, if there are no source csets for @cgrp, changing its
|
|
* controllers isn't gonna produce any task migrations and the
|
|
* write-locking can be skipped safely.
|
|
*/
|
|
has_tasks = !list_empty(&mgctx.preloaded_src_csets);
|
|
cgroup_attach_lock(has_tasks);
|
|
|
|
/* NULL dst indicates self on default hierarchy */
|
|
ret = cgroup_migrate_prepare_dst(&mgctx);
|
|
if (ret)
|
|
goto out_finish;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
list_for_each_entry(src_cset, &mgctx.preloaded_src_csets,
|
|
mg_src_preload_node) {
|
|
struct task_struct *task, *ntask;
|
|
|
|
/* all tasks in src_csets need to be migrated */
|
|
list_for_each_entry_safe(task, ntask, &src_cset->tasks, cg_list)
|
|
cgroup_migrate_add_task(task, &mgctx);
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
ret = cgroup_migrate_execute(&mgctx);
|
|
out_finish:
|
|
cgroup_migrate_finish(&mgctx);
|
|
cgroup_attach_unlock(has_tasks);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cgroup_lock_and_drain_offline - lock cgroup_mutex and drain offlined csses
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* Because css offlining is asynchronous, userland may try to re-enable a
|
|
* controller while the previous css is still around. This function grabs
|
|
* cgroup_mutex and drains the previous css instances of @cgrp's subtree.
|
|
*/
|
|
void cgroup_lock_and_drain_offline(struct cgroup *cgrp)
|
|
__acquires(&cgroup_mutex)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
restart:
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
|
|
for_each_subsys(ss, ssid) {
|
|
struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
|
|
DEFINE_WAIT(wait);
|
|
|
|
if (!css || !percpu_ref_is_dying(&css->refcnt))
|
|
continue;
|
|
|
|
cgroup_get_live(dsct);
|
|
prepare_to_wait(&dsct->offline_waitq, &wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
schedule();
|
|
finish_wait(&dsct->offline_waitq, &wait);
|
|
|
|
cgroup_put(dsct);
|
|
goto restart;
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cgroup_save_control - save control masks and dom_cgrp of a subtree
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* Save ->subtree_control, ->subtree_ss_mask and ->dom_cgrp to the
|
|
* respective old_ prefixed fields for @cgrp's subtree including @cgrp
|
|
* itself.
|
|
*/
|
|
static void cgroup_save_control(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
|
|
dsct->old_subtree_control = dsct->subtree_control;
|
|
dsct->old_subtree_ss_mask = dsct->subtree_ss_mask;
|
|
dsct->old_dom_cgrp = dsct->dom_cgrp;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cgroup_propagate_control - refresh control masks of a subtree
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* For @cgrp and its subtree, ensure ->subtree_ss_mask matches
|
|
* ->subtree_control and propagate controller availability through the
|
|
* subtree so that descendants don't have unavailable controllers enabled.
|
|
*/
|
|
static void cgroup_propagate_control(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
|
|
dsct->subtree_control &= cgroup_control(dsct);
|
|
dsct->subtree_ss_mask =
|
|
cgroup_calc_subtree_ss_mask(dsct->subtree_control,
|
|
cgroup_ss_mask(dsct));
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cgroup_restore_control - restore control masks and dom_cgrp of a subtree
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* Restore ->subtree_control, ->subtree_ss_mask and ->dom_cgrp from the
|
|
* respective old_ prefixed fields for @cgrp's subtree including @cgrp
|
|
* itself.
|
|
*/
|
|
static void cgroup_restore_control(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
|
|
cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
|
|
dsct->subtree_control = dsct->old_subtree_control;
|
|
dsct->subtree_ss_mask = dsct->old_subtree_ss_mask;
|
|
dsct->dom_cgrp = dsct->old_dom_cgrp;
|
|
}
|
|
}
|
|
|
|
static bool css_visible(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup_subsys *ss = css->ss;
|
|
struct cgroup *cgrp = css->cgroup;
|
|
|
|
if (cgroup_control(cgrp) & (1 << ss->id))
|
|
return true;
|
|
if (!(cgroup_ss_mask(cgrp) & (1 << ss->id)))
|
|
return false;
|
|
return cgroup_on_dfl(cgrp) && ss->implicit_on_dfl;
|
|
}
|
|
|
|
/**
|
|
* cgroup_apply_control_enable - enable or show csses according to control
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* Walk @cgrp's subtree and create new csses or make the existing ones
|
|
* visible. A css is created invisible if it's being implicitly enabled
|
|
* through dependency. An invisible css is made visible when the userland
|
|
* explicitly enables it.
|
|
*
|
|
* Returns 0 on success, -errno on failure. On failure, csses which have
|
|
* been processed already aren't cleaned up. The caller is responsible for
|
|
* cleaning up with cgroup_apply_control_disable().
|
|
*/
|
|
static int cgroup_apply_control_enable(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
struct cgroup_subsys *ss;
|
|
int ssid, ret;
|
|
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
|
|
for_each_subsys(ss, ssid) {
|
|
struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
|
|
|
|
if (!(cgroup_ss_mask(dsct) & (1 << ss->id)))
|
|
continue;
|
|
|
|
if (!css) {
|
|
css = css_create(dsct, ss);
|
|
if (IS_ERR(css))
|
|
return PTR_ERR(css);
|
|
}
|
|
|
|
WARN_ON_ONCE(percpu_ref_is_dying(&css->refcnt));
|
|
|
|
if (css_visible(css)) {
|
|
ret = css_populate_dir(css);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_apply_control_disable - kill or hide csses according to control
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* Walk @cgrp's subtree and kill and hide csses so that they match
|
|
* cgroup_ss_mask() and cgroup_visible_mask().
|
|
*
|
|
* A css is hidden when the userland requests it to be disabled while other
|
|
* subsystems are still depending on it. The css must not actively control
|
|
* resources and be in the vanilla state if it's made visible again later.
|
|
* Controllers which may be depended upon should provide ->css_reset() for
|
|
* this purpose.
|
|
*/
|
|
static void cgroup_apply_control_disable(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
cgroup_for_each_live_descendant_post(dsct, d_css, cgrp) {
|
|
for_each_subsys(ss, ssid) {
|
|
struct cgroup_subsys_state *css = cgroup_css(dsct, ss);
|
|
|
|
if (!css)
|
|
continue;
|
|
|
|
WARN_ON_ONCE(percpu_ref_is_dying(&css->refcnt));
|
|
|
|
if (css->parent &&
|
|
!(cgroup_ss_mask(dsct) & (1 << ss->id))) {
|
|
kill_css(css);
|
|
} else if (!css_visible(css)) {
|
|
css_clear_dir(css);
|
|
if (ss->css_reset)
|
|
ss->css_reset(css);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/**
|
|
* cgroup_apply_control - apply control mask updates to the subtree
|
|
* @cgrp: root of the target subtree
|
|
*
|
|
* subsystems can be enabled and disabled in a subtree using the following
|
|
* steps.
|
|
*
|
|
* 1. Call cgroup_save_control() to stash the current state.
|
|
* 2. Update ->subtree_control masks in the subtree as desired.
|
|
* 3. Call cgroup_apply_control() to apply the changes.
|
|
* 4. Optionally perform other related operations.
|
|
* 5. Call cgroup_finalize_control() to finish up.
|
|
*
|
|
* This function implements step 3 and propagates the mask changes
|
|
* throughout @cgrp's subtree, updates csses accordingly and perform
|
|
* process migrations.
|
|
*/
|
|
static int cgroup_apply_control(struct cgroup *cgrp)
|
|
{
|
|
int ret;
|
|
|
|
cgroup_propagate_control(cgrp);
|
|
|
|
ret = cgroup_apply_control_enable(cgrp);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/*
|
|
* At this point, cgroup_e_css_by_mask() results reflect the new csses
|
|
* making the following cgroup_update_dfl_csses() properly update
|
|
* css associations of all tasks in the subtree.
|
|
*/
|
|
ret = cgroup_update_dfl_csses(cgrp);
|
|
if (ret)
|
|
return ret;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_finalize_control - finalize control mask update
|
|
* @cgrp: root of the target subtree
|
|
* @ret: the result of the update
|
|
*
|
|
* Finalize control mask update. See cgroup_apply_control() for more info.
|
|
*/
|
|
static void cgroup_finalize_control(struct cgroup *cgrp, int ret)
|
|
{
|
|
if (ret) {
|
|
cgroup_restore_control(cgrp);
|
|
cgroup_propagate_control(cgrp);
|
|
}
|
|
|
|
cgroup_apply_control_disable(cgrp);
|
|
}
|
|
|
|
static int cgroup_vet_subtree_control_enable(struct cgroup *cgrp, u16 enable)
|
|
{
|
|
u16 domain_enable = enable & ~cgrp_dfl_threaded_ss_mask;
|
|
|
|
/* if nothing is getting enabled, nothing to worry about */
|
|
if (!enable)
|
|
return 0;
|
|
|
|
/* can @cgrp host any resources? */
|
|
if (!cgroup_is_valid_domain(cgrp->dom_cgrp))
|
|
return -EOPNOTSUPP;
|
|
|
|
/* mixables don't care */
|
|
if (cgroup_is_mixable(cgrp))
|
|
return 0;
|
|
|
|
if (domain_enable) {
|
|
/* can't enable domain controllers inside a thread subtree */
|
|
if (cgroup_is_thread_root(cgrp) || cgroup_is_threaded(cgrp))
|
|
return -EOPNOTSUPP;
|
|
} else {
|
|
/*
|
|
* Threaded controllers can handle internal competitions
|
|
* and are always allowed inside a (prospective) thread
|
|
* subtree.
|
|
*/
|
|
if (cgroup_can_be_thread_root(cgrp) || cgroup_is_threaded(cgrp))
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Controllers can't be enabled for a cgroup with tasks to avoid
|
|
* child cgroups competing against tasks.
|
|
*/
|
|
if (cgroup_has_tasks(cgrp))
|
|
return -EBUSY;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* change the enabled child controllers for a cgroup in the default hierarchy */
|
|
static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes,
|
|
loff_t off)
|
|
{
|
|
u16 enable = 0, disable = 0;
|
|
struct cgroup *cgrp, *child;
|
|
struct cgroup_subsys *ss;
|
|
char *tok;
|
|
int ssid, ret;
|
|
|
|
/*
|
|
* Parse input - space separated list of subsystem names prefixed
|
|
* with either + or -.
|
|
*/
|
|
buf = strstrip(buf);
|
|
while ((tok = strsep(&buf, " "))) {
|
|
if (tok[0] == '\0')
|
|
continue;
|
|
do_each_subsys_mask(ss, ssid, ~cgrp_dfl_inhibit_ss_mask) {
|
|
if (!cgroup_ssid_enabled(ssid) ||
|
|
strcmp(tok + 1, ss->name))
|
|
continue;
|
|
|
|
if (*tok == '+') {
|
|
enable |= 1 << ssid;
|
|
disable &= ~(1 << ssid);
|
|
} else if (*tok == '-') {
|
|
disable |= 1 << ssid;
|
|
enable &= ~(1 << ssid);
|
|
} else {
|
|
return -EINVAL;
|
|
}
|
|
break;
|
|
} while_each_subsys_mask();
|
|
if (ssid == CGROUP_SUBSYS_COUNT)
|
|
return -EINVAL;
|
|
}
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, true);
|
|
if (!cgrp)
|
|
return -ENODEV;
|
|
|
|
for_each_subsys(ss, ssid) {
|
|
if (enable & (1 << ssid)) {
|
|
if (cgrp->subtree_control & (1 << ssid)) {
|
|
enable &= ~(1 << ssid);
|
|
continue;
|
|
}
|
|
|
|
if (!(cgroup_control(cgrp) & (1 << ssid))) {
|
|
ret = -ENOENT;
|
|
goto out_unlock;
|
|
}
|
|
} else if (disable & (1 << ssid)) {
|
|
if (!(cgrp->subtree_control & (1 << ssid))) {
|
|
disable &= ~(1 << ssid);
|
|
continue;
|
|
}
|
|
|
|
/* a child has it enabled? */
|
|
cgroup_for_each_live_child(child, cgrp) {
|
|
if (child->subtree_control & (1 << ssid)) {
|
|
ret = -EBUSY;
|
|
goto out_unlock;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
if (!enable && !disable) {
|
|
ret = 0;
|
|
goto out_unlock;
|
|
}
|
|
|
|
ret = cgroup_vet_subtree_control_enable(cgrp, enable);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
/* save and update control masks and prepare csses */
|
|
cgroup_save_control(cgrp);
|
|
|
|
cgrp->subtree_control |= enable;
|
|
cgrp->subtree_control &= ~disable;
|
|
|
|
ret = cgroup_apply_control(cgrp);
|
|
cgroup_finalize_control(cgrp, ret);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
kernfs_activate(cgrp->kn);
|
|
out_unlock:
|
|
cgroup_kn_unlock(of->kn);
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
/**
|
|
* cgroup_enable_threaded - make @cgrp threaded
|
|
* @cgrp: the target cgroup
|
|
*
|
|
* Called when "threaded" is written to the cgroup.type interface file and
|
|
* tries to make @cgrp threaded and join the parent's resource domain.
|
|
* This function is never called on the root cgroup as cgroup.type doesn't
|
|
* exist on it.
|
|
*/
|
|
static int cgroup_enable_threaded(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *parent = cgroup_parent(cgrp);
|
|
struct cgroup *dom_cgrp = parent->dom_cgrp;
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
int ret;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/* noop if already threaded */
|
|
if (cgroup_is_threaded(cgrp))
|
|
return 0;
|
|
|
|
/*
|
|
* If @cgroup is populated or has domain controllers enabled, it
|
|
* can't be switched. While the below cgroup_can_be_thread_root()
|
|
* test can catch the same conditions, that's only when @parent is
|
|
* not mixable, so let's check it explicitly.
|
|
*/
|
|
if (cgroup_is_populated(cgrp) ||
|
|
cgrp->subtree_control & ~cgrp_dfl_threaded_ss_mask)
|
|
return -EOPNOTSUPP;
|
|
|
|
/* we're joining the parent's domain, ensure its validity */
|
|
if (!cgroup_is_valid_domain(dom_cgrp) ||
|
|
!cgroup_can_be_thread_root(dom_cgrp))
|
|
return -EOPNOTSUPP;
|
|
|
|
/*
|
|
* The following shouldn't cause actual migrations and should
|
|
* always succeed.
|
|
*/
|
|
cgroup_save_control(cgrp);
|
|
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp)
|
|
if (dsct == cgrp || cgroup_is_threaded(dsct))
|
|
dsct->dom_cgrp = dom_cgrp;
|
|
|
|
ret = cgroup_apply_control(cgrp);
|
|
if (!ret)
|
|
parent->nr_threaded_children++;
|
|
|
|
cgroup_finalize_control(cgrp, ret);
|
|
return ret;
|
|
}
|
|
|
|
static int cgroup_type_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
|
|
if (cgroup_is_threaded(cgrp))
|
|
seq_puts(seq, "threaded\n");
|
|
else if (!cgroup_is_valid_domain(cgrp))
|
|
seq_puts(seq, "domain invalid\n");
|
|
else if (cgroup_is_thread_root(cgrp))
|
|
seq_puts(seq, "domain threaded\n");
|
|
else
|
|
seq_puts(seq, "domain\n");
|
|
|
|
return 0;
|
|
}
|
|
|
|
int cgroup_id_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
int ssid;
|
|
struct cgroup_subsys *ss;
|
|
|
|
for_each_subsys(ss, ssid) {
|
|
struct cgroup_subsys_state *css = cgroup_css(cgrp, ss);
|
|
|
|
if (css)
|
|
seq_printf(seq, "%s:%u\n", ss->name, css->id);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t cgroup_type_write(struct kernfs_open_file *of, char *buf,
|
|
size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup *cgrp;
|
|
int ret;
|
|
|
|
/* only switching to threaded mode is supported */
|
|
if (strcmp(strstrip(buf), "threaded"))
|
|
return -EINVAL;
|
|
|
|
/* drain dying csses before we re-apply (threaded) subtree control */
|
|
cgrp = cgroup_kn_lock_live(of->kn, true);
|
|
if (!cgrp)
|
|
return -ENOENT;
|
|
|
|
/* threaded can only be enabled */
|
|
ret = cgroup_enable_threaded(cgrp);
|
|
|
|
cgroup_kn_unlock(of->kn);
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
static int cgroup_max_descendants_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
int descendants = READ_ONCE(cgrp->max_descendants);
|
|
|
|
if (descendants == INT_MAX)
|
|
seq_puts(seq, "max\n");
|
|
else
|
|
seq_printf(seq, "%d\n", descendants);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t cgroup_max_descendants_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup *cgrp;
|
|
int descendants;
|
|
ssize_t ret;
|
|
|
|
buf = strstrip(buf);
|
|
if (!strcmp(buf, "max")) {
|
|
descendants = INT_MAX;
|
|
} else {
|
|
ret = kstrtoint(buf, 0, &descendants);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
if (descendants < 0)
|
|
return -ERANGE;
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!cgrp)
|
|
return -ENOENT;
|
|
|
|
cgrp->max_descendants = descendants;
|
|
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static int cgroup_max_depth_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
int depth = READ_ONCE(cgrp->max_depth);
|
|
|
|
if (depth == INT_MAX)
|
|
seq_puts(seq, "max\n");
|
|
else
|
|
seq_printf(seq, "%d\n", depth);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t cgroup_max_depth_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup *cgrp;
|
|
ssize_t ret;
|
|
int depth;
|
|
|
|
buf = strstrip(buf);
|
|
if (!strcmp(buf, "max")) {
|
|
depth = INT_MAX;
|
|
} else {
|
|
ret = kstrtoint(buf, 0, &depth);
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
if (depth < 0)
|
|
return -ERANGE;
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!cgrp)
|
|
return -ENOENT;
|
|
|
|
cgrp->max_depth = depth;
|
|
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static int cgroup_events_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
|
|
seq_printf(seq, "populated %d\n", cgroup_is_populated(cgrp));
|
|
seq_printf(seq, "frozen %d\n", test_bit(CGRP_FROZEN, &cgrp->flags));
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cgroup_stat_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
|
|
seq_printf(seq, "nr_descendants %d\n",
|
|
cgroup->nr_descendants);
|
|
seq_printf(seq, "nr_dying_descendants %d\n",
|
|
cgroup->nr_dying_descendants);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __maybe_unused cgroup_extra_stat_show(struct seq_file *seq,
|
|
struct cgroup *cgrp, int ssid)
|
|
{
|
|
struct cgroup_subsys *ss = cgroup_subsys[ssid];
|
|
struct cgroup_subsys_state *css;
|
|
int ret;
|
|
|
|
if (!ss->css_extra_stat_show)
|
|
return 0;
|
|
|
|
css = cgroup_tryget_css(cgrp, ss);
|
|
if (!css)
|
|
return 0;
|
|
|
|
ret = ss->css_extra_stat_show(seq, css);
|
|
css_put(css);
|
|
return ret;
|
|
}
|
|
|
|
static int cpu_stat_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup __maybe_unused *cgrp = seq_css(seq)->cgroup;
|
|
int ret = 0;
|
|
|
|
cgroup_base_stat_cputime_show(seq);
|
|
#ifdef CONFIG_CGROUP_SCHED
|
|
ret = cgroup_extra_stat_show(seq, cgrp, cpu_cgrp_id);
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
#ifdef CONFIG_PSI
|
|
int cgroup_io_pressure_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
struct psi_group *psi = cgroup->id == 1 ? &psi_system : &cgroup->psi;
|
|
|
|
return psi_show(seq, psi, PSI_IO);
|
|
}
|
|
int cgroup_memory_pressure_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
struct psi_group *psi = cgroup->id == 1 ? &psi_system : &cgroup->psi;
|
|
|
|
return psi_show(seq, psi, PSI_MEM);
|
|
}
|
|
int cgroup_cpu_pressure_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
struct psi_group *psi = cgroup->id == 1 ? &psi_system : &cgroup->psi;
|
|
|
|
return psi_show(seq, psi, PSI_CPU);
|
|
}
|
|
|
|
ssize_t cgroup_pressure_write(struct kernfs_open_file *of, char *buf,
|
|
size_t nbytes, enum psi_res res)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
struct psi_trigger *new;
|
|
struct cgroup *cgrp;
|
|
struct psi_group *psi;
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!cgrp)
|
|
return -ENODEV;
|
|
|
|
cgroup_get(cgrp);
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
/* Allow only one trigger per file descriptor */
|
|
if (ctx->psi.trigger) {
|
|
cgroup_put(cgrp);
|
|
return -EBUSY;
|
|
}
|
|
|
|
psi = cgroup_ino(cgrp) == 1 ? &psi_system : &cgrp->psi;
|
|
new = psi_trigger_create(psi, buf, nbytes, res);
|
|
if (IS_ERR(new)) {
|
|
cgroup_put(cgrp);
|
|
return PTR_ERR(new);
|
|
}
|
|
|
|
smp_store_release(&ctx->psi.trigger, new);
|
|
cgroup_put(cgrp);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
ssize_t cgroup_io_pressure_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes,
|
|
loff_t off)
|
|
{
|
|
return cgroup_pressure_write(of, buf, nbytes, PSI_IO);
|
|
}
|
|
|
|
ssize_t cgroup_memory_pressure_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes,
|
|
loff_t off)
|
|
{
|
|
return cgroup_pressure_write(of, buf, nbytes, PSI_MEM);
|
|
}
|
|
|
|
ssize_t cgroup_cpu_pressure_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes,
|
|
loff_t off)
|
|
{
|
|
return cgroup_pressure_write(of, buf, nbytes, PSI_CPU);
|
|
}
|
|
|
|
struct poll_table_struct;
|
|
__poll_t cgroup_pressure_poll(struct kernfs_open_file *of,
|
|
poll_table *pt)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
return psi_trigger_poll(&ctx->psi.trigger, of->file, pt);
|
|
}
|
|
|
|
void cgroup_pressure_release(struct kernfs_open_file *of)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
|
|
psi_trigger_destroy(ctx->psi.trigger);
|
|
}
|
|
#endif /* CONFIG_PSI */
|
|
|
|
#ifdef CONFIG_RQM
|
|
static void cgroup_quality_release(struct kernfs_open_file *of)
|
|
{
|
|
}
|
|
|
|
static void cgroup_cpu_release(struct kernfs_open_file *of)
|
|
{
|
|
}
|
|
|
|
static void cgroup_mem_release(struct kernfs_open_file *of)
|
|
{
|
|
}
|
|
|
|
static void cgroup_net_release(struct kernfs_open_file *of)
|
|
{
|
|
}
|
|
|
|
static int cgroup_io_quality_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
struct rqm_group *rqm = cgroup->id == 1 ? &rqm_system : &cgroup->rqm;
|
|
|
|
return rqm_show(seq, rqm, RQM_IO);
|
|
}
|
|
|
|
static int cgroup_mem_quality_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
struct cgroup_rstat_cpu *rstatc;
|
|
unsigned long long alloc_ticks = 0, alloc_stall = 0;
|
|
int order, cpu;
|
|
|
|
for_each_online_cpu(cpu) {
|
|
rstatc = per_cpu_ptr(cgroup->rstat_cpu, cpu);
|
|
for (order = 0; order < MAX_ORDER; order ++) {
|
|
alloc_ticks += rstatc->rqm_mem_stat[order].cgroup_mem_ticks
|
|
* (1 << order);
|
|
alloc_stall += rstatc->rqm_mem_stat[order].cgroup_mem_stall;
|
|
}
|
|
}
|
|
|
|
seq_printf(seq, "%llu %llu\n", alloc_ticks, alloc_stall);
|
|
return 0;
|
|
}
|
|
|
|
static int cgroup_cpu_quality_show(struct seq_file *seq, void *v)
|
|
{
|
|
int cpu;
|
|
unsigned long long prio_stall = 0, stall = 0, exec_runtime = 0;
|
|
struct cgroup_rstat_cpu *rstatc;
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
|
|
for_each_online_cpu(cpu) {
|
|
rstatc = per_cpu_ptr(cgroup->rstat_cpu, cpu);
|
|
exec_runtime += rstatc->bstat.cputime.sum_exec_runtime;
|
|
stall += rstatc->rqm_stat.cgroup_stalled_time;
|
|
prio_stall += rstatc->rqm_stat.cgroup_prio_stalled_time;
|
|
}
|
|
|
|
seq_printf(seq, "%llu %llu %llu\n", exec_runtime, stall, prio_stall);
|
|
return 0;
|
|
}
|
|
|
|
static int cgroup_net_quality_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
struct rqm_group *rqm = cgroup->id == 1 ? &rqm_system : &cgroup->rqm;
|
|
|
|
return rqm_show(seq, rqm, RQM_NET);
|
|
}
|
|
#endif
|
|
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
static int cgroup_sli_memory_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
|
|
return sli_memlat_stat_show(seq,cgroup);
|
|
}
|
|
|
|
static int cgroup_sli_cpu_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
|
|
return sli_schedlat_stat_show(seq,cgroup);
|
|
}
|
|
|
|
static int cgroup_sli_max_show(struct seq_file *seq, void *v)
|
|
{
|
|
|
|
struct cgroup *cgroup = seq_css(seq)->cgroup;
|
|
|
|
sli_schedlat_max_show(seq, cgroup);
|
|
return sli_memlat_max_show(seq, cgroup);
|
|
}
|
|
#endif
|
|
|
|
void *cgroup_mbuf_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
struct cgroup *cgrp = seq_css(s)->cgroup;
|
|
struct mbuf_slot *mb = cgrp->mbuf;
|
|
u32 index;
|
|
|
|
if (!mb)
|
|
return NULL;
|
|
|
|
index = *pos;
|
|
/* If already reach end, just return */
|
|
if (index && index == mb->mring->next_idx)
|
|
return NULL;
|
|
|
|
if (!mb->udesc) {
|
|
mb->udesc = kmalloc(sizeof(struct mbuf_user_desc), GFP_KERNEL);
|
|
|
|
if (!mb->udesc)
|
|
goto out;
|
|
|
|
mb->udesc->user_idx = mb->mring->first_idx;
|
|
mb->udesc->user_seq = mb->mring->first_seq;
|
|
}
|
|
|
|
/* Maybe reach end or empty */
|
|
if (mb->udesc->user_idx == mb->mring->next_idx)
|
|
return NULL;
|
|
|
|
out:
|
|
return mb->udesc;
|
|
}
|
|
|
|
void *cgroup_mbuf_next(struct seq_file *s, void *v, loff_t *pos)
|
|
{
|
|
struct mbuf_user_desc *udesc = (struct mbuf_user_desc *)v;
|
|
struct cgroup *cgrp = seq_css(s)->cgroup;
|
|
struct mbuf_slot *mb = cgrp->mbuf;
|
|
|
|
udesc->user_idx = mb->ops->next(mb->mring, udesc->user_idx);
|
|
*pos = udesc->user_idx;
|
|
|
|
if (udesc->user_idx == mb->mring->next_idx)
|
|
return NULL;
|
|
|
|
return udesc;
|
|
}
|
|
|
|
void cgroup_mbuf_stop(struct seq_file *s, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(s)->cgroup;
|
|
struct mbuf_user_desc *desc;
|
|
|
|
if (cgrp->mbuf) {
|
|
desc = cgrp->mbuf->udesc;
|
|
if(desc && desc->user_idx == cgrp->mbuf->mring->next_idx) {
|
|
kfree(cgrp->mbuf->udesc);
|
|
cgrp->mbuf->udesc = NULL;
|
|
}
|
|
}
|
|
}
|
|
|
|
int cgroup_mbuf_show(struct seq_file *s, void *v)
|
|
{
|
|
ssize_t ret;
|
|
struct mbuf_user_desc *udesc = (struct mbuf_user_desc *)v;
|
|
struct cgroup *cgrp = seq_css(s)->cgroup;
|
|
struct mbuf_slot *mb = cgrp->mbuf;
|
|
|
|
memset(udesc->buf, 0, sizeof(udesc->buf));
|
|
ret = mb->ops->read(mb, udesc);
|
|
|
|
if (ret > 0)
|
|
seq_printf(s, "%s", udesc->buf);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Get cgroup struct from task_struct for mbuf and sli.
|
|
*
|
|
* In cgroup V1, return cpuacct cgroup, and if cpuacct cgroup is root, df1_cgrp
|
|
* is returned, but is harmless.
|
|
*
|
|
* In cgroup V2, just return task_struct.cgroups.dfl_cgrp.
|
|
*/
|
|
struct cgroup *get_cgroup_from_task(struct task_struct *task)
|
|
{
|
|
struct cgroup *cgrp;
|
|
|
|
/* First, try to get cpuacct cgroup for V1*/
|
|
cgrp = task_cgroup(task, cpuacct_cgrp_id);
|
|
if (cgrp && cgrp->level)
|
|
return cgrp;
|
|
|
|
/*
|
|
* If can not find cpuacct cgroup or cpuacct cgroup is root, just return
|
|
* dfl_cgrp.
|
|
*/
|
|
cgrp = task_dfl_cgroup(task);
|
|
|
|
return cgrp;
|
|
}
|
|
|
|
/* Store info to mbuf according task_struct */
|
|
ssize_t mbuf_print_task(struct task_struct *task, const char *fmt, ...)
|
|
{
|
|
struct cgroup *cgrp;
|
|
struct mbuf_slot *mb;
|
|
va_list args;
|
|
|
|
cgrp = get_cgroup_from_task(task);
|
|
mb = cgrp->mbuf;
|
|
if(!sysctl_qos_mbuf_enable || !mb)
|
|
goto out;
|
|
|
|
if(!__ratelimit(&mb->ratelimit)) {
|
|
goto out;
|
|
}
|
|
|
|
if (mb->ops) {
|
|
va_start(args, fmt);
|
|
mb->ops->write(cgrp, fmt, args);
|
|
va_end(args);
|
|
}
|
|
|
|
out:
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(mbuf_print_task);
|
|
|
|
ssize_t mbuf_print(struct cgroup *cgrp, const char *fmt, ...)
|
|
{
|
|
struct mbuf_slot *mb;
|
|
va_list args;
|
|
|
|
mb = cgrp->mbuf;
|
|
if(!sysctl_qos_mbuf_enable || !mb)
|
|
goto out;
|
|
|
|
if(!__ratelimit(&mb->ratelimit)) {
|
|
goto out;
|
|
}
|
|
|
|
if (mb->ops) {
|
|
va_start(args, fmt);
|
|
mb->ops->write(cgrp, fmt, args);
|
|
va_end(args);
|
|
}
|
|
|
|
out:
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(mbuf_print);
|
|
|
|
static int cgroup_freeze_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
|
|
seq_printf(seq, "%d\n", cgrp->freezer.freeze);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t cgroup_freeze_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup *cgrp;
|
|
ssize_t ret;
|
|
int freeze;
|
|
|
|
ret = kstrtoint(strstrip(buf), 0, &freeze);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (freeze < 0 || freeze > 1)
|
|
return -ERANGE;
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!cgrp)
|
|
return -ENOENT;
|
|
|
|
cgroup_freeze(cgrp, freeze);
|
|
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return nbytes;
|
|
}
|
|
|
|
static int cgroup_file_open(struct kernfs_open_file *of)
|
|
{
|
|
struct cftype *cft = of->kn->priv;
|
|
struct cgroup_file_ctx *ctx;
|
|
int ret;
|
|
|
|
ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
|
|
if (!ctx)
|
|
return -ENOMEM;
|
|
|
|
ctx->ns = current->nsproxy->cgroup_ns;
|
|
get_cgroup_ns(ctx->ns);
|
|
of->priv = ctx;
|
|
|
|
if (!cft->open)
|
|
return 0;
|
|
|
|
ret = cft->open(of);
|
|
if (ret) {
|
|
put_cgroup_ns(ctx->ns);
|
|
kfree(ctx);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void cgroup_file_release(struct kernfs_open_file *of)
|
|
{
|
|
struct cftype *cft = of->kn->priv;
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
|
|
if (cft->release)
|
|
cft->release(of);
|
|
put_cgroup_ns(ctx->ns);
|
|
kfree(ctx);
|
|
}
|
|
|
|
static ssize_t cgroup_file_write(struct kernfs_open_file *of, char *buf,
|
|
size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
struct cgroup *cgrp = of->kn->parent->priv;
|
|
struct cftype *cft = of->kn->priv;
|
|
struct cgroup_subsys_state *css;
|
|
int ret;
|
|
|
|
/*
|
|
* If namespaces are delegation boundaries, disallow writes to
|
|
* files in an non-init namespace root from inside the namespace
|
|
* except for the files explicitly marked delegatable -
|
|
* cgroup.procs and cgroup.subtree_control.
|
|
*/
|
|
if ((cgrp->root->flags & CGRP_ROOT_NS_DELEGATE) &&
|
|
!(cft->flags & CFTYPE_NS_DELEGATABLE) &&
|
|
ctx->ns != &init_cgroup_ns && ctx->ns->root_cset->dfl_cgrp == cgrp)
|
|
return -EPERM;
|
|
|
|
if (cft->write)
|
|
return cft->write(of, buf, nbytes, off);
|
|
|
|
/*
|
|
* kernfs guarantees that a file isn't deleted with operations in
|
|
* flight, which means that the matching css is and stays alive and
|
|
* doesn't need to be pinned. The RCU locking is not necessary
|
|
* either. It's just for the convenience of using cgroup_css().
|
|
*/
|
|
rcu_read_lock();
|
|
css = cgroup_css(cgrp, cft->ss);
|
|
rcu_read_unlock();
|
|
|
|
if (cft->write_u64) {
|
|
unsigned long long v;
|
|
ret = kstrtoull(buf, 0, &v);
|
|
if (!ret)
|
|
ret = cft->write_u64(css, cft, v);
|
|
} else if (cft->write_s64) {
|
|
long long v;
|
|
ret = kstrtoll(buf, 0, &v);
|
|
if (!ret)
|
|
ret = cft->write_s64(css, cft, v);
|
|
} else {
|
|
ret = -EINVAL;
|
|
}
|
|
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
static __poll_t cgroup_file_poll(struct kernfs_open_file *of, poll_table *pt)
|
|
{
|
|
struct cftype *cft = of->kn->priv;
|
|
|
|
if (cft->poll)
|
|
return cft->poll(of, pt);
|
|
|
|
return kernfs_generic_poll(of, pt);
|
|
}
|
|
|
|
static void *cgroup_seqfile_start(struct seq_file *seq, loff_t *ppos)
|
|
{
|
|
return seq_cft(seq)->seq_start(seq, ppos);
|
|
}
|
|
|
|
static void *cgroup_seqfile_next(struct seq_file *seq, void *v, loff_t *ppos)
|
|
{
|
|
return seq_cft(seq)->seq_next(seq, v, ppos);
|
|
}
|
|
|
|
static void cgroup_seqfile_stop(struct seq_file *seq, void *v)
|
|
{
|
|
if (seq_cft(seq)->seq_stop)
|
|
seq_cft(seq)->seq_stop(seq, v);
|
|
}
|
|
|
|
static int cgroup_seqfile_show(struct seq_file *m, void *arg)
|
|
{
|
|
struct cftype *cft = seq_cft(m);
|
|
struct cgroup_subsys_state *css = seq_css(m);
|
|
|
|
if (cft->seq_show)
|
|
return cft->seq_show(m, arg);
|
|
|
|
if (cft->read_u64)
|
|
seq_printf(m, "%llu\n", cft->read_u64(css, cft));
|
|
else if (cft->read_s64)
|
|
seq_printf(m, "%lld\n", cft->read_s64(css, cft));
|
|
else
|
|
return -EINVAL;
|
|
return 0;
|
|
}
|
|
|
|
static struct kernfs_ops cgroup_kf_single_ops = {
|
|
.atomic_write_len = PAGE_SIZE,
|
|
.open = cgroup_file_open,
|
|
.release = cgroup_file_release,
|
|
.write = cgroup_file_write,
|
|
.poll = cgroup_file_poll,
|
|
.seq_show = cgroup_seqfile_show,
|
|
};
|
|
|
|
static struct kernfs_ops cgroup_kf_ops = {
|
|
.atomic_write_len = PAGE_SIZE,
|
|
.open = cgroup_file_open,
|
|
.release = cgroup_file_release,
|
|
.write = cgroup_file_write,
|
|
.poll = cgroup_file_poll,
|
|
.seq_start = cgroup_seqfile_start,
|
|
.seq_next = cgroup_seqfile_next,
|
|
.seq_stop = cgroup_seqfile_stop,
|
|
.seq_show = cgroup_seqfile_show,
|
|
};
|
|
|
|
/* set uid and gid of cgroup dirs and files to that of the creator */
|
|
static int cgroup_kn_set_ugid(struct kernfs_node *kn)
|
|
{
|
|
struct iattr iattr = { .ia_valid = ATTR_UID | ATTR_GID,
|
|
.ia_uid = current_fsuid(),
|
|
.ia_gid = current_fsgid(), };
|
|
|
|
if (uid_eq(iattr.ia_uid, GLOBAL_ROOT_UID) &&
|
|
gid_eq(iattr.ia_gid, GLOBAL_ROOT_GID))
|
|
return 0;
|
|
|
|
return kernfs_setattr(kn, &iattr);
|
|
}
|
|
|
|
static void cgroup_file_notify_timer(struct timer_list *timer)
|
|
{
|
|
cgroup_file_notify(container_of(timer, struct cgroup_file,
|
|
notify_timer));
|
|
}
|
|
|
|
static int cgroup_add_file(struct cgroup_subsys_state *css, struct cgroup *cgrp,
|
|
struct cftype *cft)
|
|
{
|
|
char name[CGROUP_FILE_NAME_MAX];
|
|
struct kernfs_node *kn;
|
|
struct lock_class_key *key = NULL;
|
|
int ret;
|
|
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
key = &cft->lockdep_key;
|
|
#endif
|
|
kn = __kernfs_create_file(cgrp->kn, cgroup_file_name(cgrp, cft, name),
|
|
cgroup_file_mode(cft),
|
|
GLOBAL_ROOT_UID, GLOBAL_ROOT_GID,
|
|
0, cft->kf_ops, cft,
|
|
NULL, key);
|
|
if (IS_ERR(kn))
|
|
return PTR_ERR(kn);
|
|
|
|
ret = cgroup_kn_set_ugid(kn);
|
|
if (ret) {
|
|
kernfs_remove(kn);
|
|
return ret;
|
|
}
|
|
|
|
if (cft->file_offset) {
|
|
struct cgroup_file *cfile = (void *)css + cft->file_offset;
|
|
|
|
timer_setup(&cfile->notify_timer, cgroup_file_notify_timer, 0);
|
|
|
|
spin_lock_irq(&cgroup_file_kn_lock);
|
|
cfile->kn = kn;
|
|
spin_unlock_irq(&cgroup_file_kn_lock);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_addrm_files - add or remove files to a cgroup directory
|
|
* @css: the target css
|
|
* @cgrp: the target cgroup (usually css->cgroup)
|
|
* @cfts: array of cftypes to be added
|
|
* @is_add: whether to add or remove
|
|
*
|
|
* Depending on @is_add, add or remove files defined by @cfts on @cgrp.
|
|
* For removals, this function never fails.
|
|
*/
|
|
static int cgroup_addrm_files(struct cgroup_subsys_state *css,
|
|
struct cgroup *cgrp, struct cftype cfts[],
|
|
bool is_add)
|
|
{
|
|
struct cftype *cft, *cft_end = NULL;
|
|
int ret = 0;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
restart:
|
|
for (cft = cfts; cft != cft_end && cft->name[0] != '\0'; cft++) {
|
|
/* does cft->flags tell us to skip this file on @cgrp? */
|
|
if ((cft->flags & __CFTYPE_ONLY_ON_DFL) && !cgroup_on_dfl(cgrp))
|
|
continue;
|
|
if ((cft->flags & __CFTYPE_NOT_ON_DFL) && cgroup_on_dfl(cgrp))
|
|
continue;
|
|
if ((cft->flags & CFTYPE_NOT_ON_ROOT) && !cgroup_parent(cgrp))
|
|
continue;
|
|
if ((cft->flags & CFTYPE_ONLY_ON_ROOT) && cgroup_parent(cgrp))
|
|
continue;
|
|
if ((cft->flags & CFTYPE_DEBUG) && !cgroup_debug)
|
|
continue;
|
|
if (is_add) {
|
|
ret = cgroup_add_file(css, cgrp, cft);
|
|
if (ret) {
|
|
pr_warn("%s: failed to add %s, err=%d\n",
|
|
__func__, cft->name, ret);
|
|
cft_end = cft;
|
|
is_add = false;
|
|
goto restart;
|
|
}
|
|
} else {
|
|
cgroup_rm_file(cgrp, cft);
|
|
}
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int cgroup_apply_cftypes(struct cftype *cfts, bool is_add)
|
|
{
|
|
struct cgroup_subsys *ss = cfts[0].ss;
|
|
struct cgroup *root = &ss->root->cgrp;
|
|
struct cgroup_subsys_state *css;
|
|
int ret = 0;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/* add/rm files for all cgroups created before */
|
|
css_for_each_descendant_pre(css, cgroup_css(root, ss)) {
|
|
struct cgroup *cgrp = css->cgroup;
|
|
|
|
if (!(css->flags & CSS_VISIBLE))
|
|
continue;
|
|
|
|
ret = cgroup_addrm_files(css, cgrp, cfts, is_add);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
if (is_add && !ret)
|
|
kernfs_activate(root->kn);
|
|
return ret;
|
|
}
|
|
|
|
static void cgroup_exit_cftypes(struct cftype *cfts)
|
|
{
|
|
struct cftype *cft;
|
|
|
|
for (cft = cfts; cft->name[0] != '\0'; cft++) {
|
|
/* free copy for custom atomic_write_len, see init_cftypes() */
|
|
if (cft->max_write_len && cft->max_write_len != PAGE_SIZE)
|
|
kfree(cft->kf_ops);
|
|
cft->kf_ops = NULL;
|
|
cft->ss = NULL;
|
|
|
|
/* revert flags set by cgroup core while adding @cfts */
|
|
cft->flags &= ~(__CFTYPE_ONLY_ON_DFL | __CFTYPE_NOT_ON_DFL);
|
|
}
|
|
}
|
|
|
|
static int cgroup_init_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
|
|
{
|
|
struct cftype *cft;
|
|
|
|
for (cft = cfts; cft->name[0] != '\0'; cft++) {
|
|
struct kernfs_ops *kf_ops;
|
|
|
|
WARN_ON(cft->ss || cft->kf_ops);
|
|
|
|
if (cft->seq_start)
|
|
kf_ops = &cgroup_kf_ops;
|
|
else
|
|
kf_ops = &cgroup_kf_single_ops;
|
|
|
|
/*
|
|
* Ugh... if @cft wants a custom max_write_len, we need to
|
|
* make a copy of kf_ops to set its atomic_write_len.
|
|
*/
|
|
if (cft->max_write_len && cft->max_write_len != PAGE_SIZE) {
|
|
kf_ops = kmemdup(kf_ops, sizeof(*kf_ops), GFP_KERNEL);
|
|
if (!kf_ops) {
|
|
cgroup_exit_cftypes(cfts);
|
|
return -ENOMEM;
|
|
}
|
|
kf_ops->atomic_write_len = cft->max_write_len;
|
|
}
|
|
|
|
cft->kf_ops = kf_ops;
|
|
cft->ss = ss;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int cgroup_rm_cftypes_locked(struct cftype *cfts)
|
|
{
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
if (!cfts || !cfts[0].ss)
|
|
return -ENOENT;
|
|
|
|
list_del(&cfts->node);
|
|
cgroup_apply_cftypes(cfts, false);
|
|
cgroup_exit_cftypes(cfts);
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_rm_cftypes - remove an array of cftypes from a subsystem
|
|
* @cfts: zero-length name terminated array of cftypes
|
|
*
|
|
* Unregister @cfts. Files described by @cfts are removed from all
|
|
* existing cgroups and all future cgroups won't have them either. This
|
|
* function can be called anytime whether @cfts' subsys is attached or not.
|
|
*
|
|
* Returns 0 on successful unregistration, -ENOENT if @cfts is not
|
|
* registered.
|
|
*/
|
|
int cgroup_rm_cftypes(struct cftype *cfts)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
ret = cgroup_rm_cftypes_locked(cfts);
|
|
mutex_unlock(&cgroup_mutex);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cgroup_add_cftypes - add an array of cftypes to a subsystem
|
|
* @ss: target cgroup subsystem
|
|
* @cfts: zero-length name terminated array of cftypes
|
|
*
|
|
* Register @cfts to @ss. Files described by @cfts are created for all
|
|
* existing cgroups to which @ss is attached and all future cgroups will
|
|
* have them too. This function can be called anytime whether @ss is
|
|
* attached or not.
|
|
*
|
|
* Returns 0 on successful registration, -errno on failure. Note that this
|
|
* function currently returns 0 as long as @cfts registration is successful
|
|
* even if some file creation attempts on existing cgroups fail.
|
|
*/
|
|
static int cgroup_add_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
|
|
{
|
|
int ret;
|
|
|
|
if (!cgroup_ssid_enabled(ss->id))
|
|
return 0;
|
|
|
|
if (!cfts || cfts[0].name[0] == '\0')
|
|
return 0;
|
|
|
|
ret = cgroup_init_cftypes(ss, cfts);
|
|
if (ret)
|
|
return ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
list_add_tail(&cfts->node, &ss->cfts);
|
|
ret = cgroup_apply_cftypes(cfts, true);
|
|
if (ret)
|
|
cgroup_rm_cftypes_locked(cfts);
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cgroup_add_dfl_cftypes - add an array of cftypes for default hierarchy
|
|
* @ss: target cgroup subsystem
|
|
* @cfts: zero-length name terminated array of cftypes
|
|
*
|
|
* Similar to cgroup_add_cftypes() but the added files are only used for
|
|
* the default hierarchy.
|
|
*/
|
|
int cgroup_add_dfl_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
|
|
{
|
|
struct cftype *cft;
|
|
|
|
for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
|
|
cft->flags |= __CFTYPE_ONLY_ON_DFL;
|
|
return cgroup_add_cftypes(ss, cfts);
|
|
}
|
|
|
|
/**
|
|
* cgroup_add_legacy_cftypes - add an array of cftypes for legacy hierarchies
|
|
* @ss: target cgroup subsystem
|
|
* @cfts: zero-length name terminated array of cftypes
|
|
*
|
|
* Similar to cgroup_add_cftypes() but the added files are only used for
|
|
* the legacy hierarchies.
|
|
*/
|
|
int cgroup_add_legacy_cftypes(struct cgroup_subsys *ss, struct cftype *cfts)
|
|
{
|
|
struct cftype *cft;
|
|
|
|
for (cft = cfts; cft && cft->name[0] != '\0'; cft++)
|
|
cft->flags |= __CFTYPE_NOT_ON_DFL;
|
|
return cgroup_add_cftypes(ss, cfts);
|
|
}
|
|
|
|
/**
|
|
* cgroup_file_notify - generate a file modified event for a cgroup_file
|
|
* @cfile: target cgroup_file
|
|
*
|
|
* @cfile must have been obtained by setting cftype->file_offset.
|
|
*/
|
|
void cgroup_file_notify(struct cgroup_file *cfile)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cgroup_file_kn_lock, flags);
|
|
if (cfile->kn) {
|
|
unsigned long last = cfile->notified_at;
|
|
unsigned long next = last + CGROUP_FILE_NOTIFY_MIN_INTV;
|
|
|
|
if (time_in_range(jiffies, last, next)) {
|
|
timer_reduce(&cfile->notify_timer, next);
|
|
} else {
|
|
kernfs_notify(cfile->kn);
|
|
cfile->notified_at = jiffies;
|
|
}
|
|
}
|
|
spin_unlock_irqrestore(&cgroup_file_kn_lock, flags);
|
|
}
|
|
|
|
/**
|
|
* css_next_child - find the next child of a given css
|
|
* @pos: the current position (%NULL to initiate traversal)
|
|
* @parent: css whose children to walk
|
|
*
|
|
* This function returns the next child of @parent and should be called
|
|
* under either cgroup_mutex or RCU read lock. The only requirement is
|
|
* that @parent and @pos are accessible. The next sibling is guaranteed to
|
|
* be returned regardless of their states.
|
|
*
|
|
* If a subsystem synchronizes ->css_online() and the start of iteration, a
|
|
* css which finished ->css_online() is guaranteed to be visible in the
|
|
* future iterations and will stay visible until the last reference is put.
|
|
* A css which hasn't finished ->css_online() or already finished
|
|
* ->css_offline() may show up during traversal. It's each subsystem's
|
|
* responsibility to synchronize against on/offlining.
|
|
*/
|
|
struct cgroup_subsys_state *css_next_child(struct cgroup_subsys_state *pos,
|
|
struct cgroup_subsys_state *parent)
|
|
{
|
|
struct cgroup_subsys_state *next;
|
|
|
|
cgroup_assert_mutex_or_rcu_locked();
|
|
|
|
/*
|
|
* @pos could already have been unlinked from the sibling list.
|
|
* Once a cgroup is removed, its ->sibling.next is no longer
|
|
* updated when its next sibling changes. CSS_RELEASED is set when
|
|
* @pos is taken off list, at which time its next pointer is valid,
|
|
* and, as releases are serialized, the one pointed to by the next
|
|
* pointer is guaranteed to not have started release yet. This
|
|
* implies that if we observe !CSS_RELEASED on @pos in this RCU
|
|
* critical section, the one pointed to by its next pointer is
|
|
* guaranteed to not have finished its RCU grace period even if we
|
|
* have dropped rcu_read_lock() inbetween iterations.
|
|
*
|
|
* If @pos has CSS_RELEASED set, its next pointer can't be
|
|
* dereferenced; however, as each css is given a monotonically
|
|
* increasing unique serial number and always appended to the
|
|
* sibling list, the next one can be found by walking the parent's
|
|
* children until the first css with higher serial number than
|
|
* @pos's. While this path can be slower, it happens iff iteration
|
|
* races against release and the race window is very small.
|
|
*/
|
|
if (!pos) {
|
|
next = list_entry_rcu(parent->children.next, struct cgroup_subsys_state, sibling);
|
|
} else if (likely(!(pos->flags & CSS_RELEASED))) {
|
|
next = list_entry_rcu(pos->sibling.next, struct cgroup_subsys_state, sibling);
|
|
} else {
|
|
list_for_each_entry_rcu(next, &parent->children, sibling)
|
|
if (next->serial_nr > pos->serial_nr)
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* @next, if not pointing to the head, can be dereferenced and is
|
|
* the next sibling.
|
|
*/
|
|
if (&next->sibling != &parent->children)
|
|
return next;
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* css_next_descendant_pre - find the next descendant for pre-order walk
|
|
* @pos: the current position (%NULL to initiate traversal)
|
|
* @root: css whose descendants to walk
|
|
*
|
|
* To be used by css_for_each_descendant_pre(). Find the next descendant
|
|
* to visit for pre-order traversal of @root's descendants. @root is
|
|
* included in the iteration and the first node to be visited.
|
|
*
|
|
* While this function requires cgroup_mutex or RCU read locking, it
|
|
* doesn't require the whole traversal to be contained in a single critical
|
|
* section. This function will return the correct next descendant as long
|
|
* as both @pos and @root are accessible and @pos is a descendant of @root.
|
|
*
|
|
* If a subsystem synchronizes ->css_online() and the start of iteration, a
|
|
* css which finished ->css_online() is guaranteed to be visible in the
|
|
* future iterations and will stay visible until the last reference is put.
|
|
* A css which hasn't finished ->css_online() or already finished
|
|
* ->css_offline() may show up during traversal. It's each subsystem's
|
|
* responsibility to synchronize against on/offlining.
|
|
*/
|
|
struct cgroup_subsys_state *
|
|
css_next_descendant_pre(struct cgroup_subsys_state *pos,
|
|
struct cgroup_subsys_state *root)
|
|
{
|
|
struct cgroup_subsys_state *next;
|
|
|
|
cgroup_assert_mutex_or_rcu_locked();
|
|
|
|
/* if first iteration, visit @root */
|
|
if (!pos)
|
|
return root;
|
|
|
|
/* visit the first child if exists */
|
|
next = css_next_child(NULL, pos);
|
|
if (next)
|
|
return next;
|
|
|
|
/* no child, visit my or the closest ancestor's next sibling */
|
|
while (pos != root) {
|
|
next = css_next_child(pos, pos->parent);
|
|
if (next)
|
|
return next;
|
|
pos = pos->parent;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_GPL(css_next_descendant_pre);
|
|
|
|
/**
|
|
* css_rightmost_descendant - return the rightmost descendant of a css
|
|
* @pos: css of interest
|
|
*
|
|
* Return the rightmost descendant of @pos. If there's no descendant, @pos
|
|
* is returned. This can be used during pre-order traversal to skip
|
|
* subtree of @pos.
|
|
*
|
|
* While this function requires cgroup_mutex or RCU read locking, it
|
|
* doesn't require the whole traversal to be contained in a single critical
|
|
* section. This function will return the correct rightmost descendant as
|
|
* long as @pos is accessible.
|
|
*/
|
|
struct cgroup_subsys_state *
|
|
css_rightmost_descendant(struct cgroup_subsys_state *pos)
|
|
{
|
|
struct cgroup_subsys_state *last, *tmp;
|
|
|
|
cgroup_assert_mutex_or_rcu_locked();
|
|
|
|
do {
|
|
last = pos;
|
|
/* ->prev isn't RCU safe, walk ->next till the end */
|
|
pos = NULL;
|
|
css_for_each_child(tmp, last)
|
|
pos = tmp;
|
|
} while (pos);
|
|
|
|
return last;
|
|
}
|
|
|
|
static struct cgroup_subsys_state *
|
|
css_leftmost_descendant(struct cgroup_subsys_state *pos)
|
|
{
|
|
struct cgroup_subsys_state *last;
|
|
|
|
do {
|
|
last = pos;
|
|
pos = css_next_child(NULL, pos);
|
|
} while (pos);
|
|
|
|
return last;
|
|
}
|
|
|
|
/**
|
|
* css_next_descendant_post - find the next descendant for post-order walk
|
|
* @pos: the current position (%NULL to initiate traversal)
|
|
* @root: css whose descendants to walk
|
|
*
|
|
* To be used by css_for_each_descendant_post(). Find the next descendant
|
|
* to visit for post-order traversal of @root's descendants. @root is
|
|
* included in the iteration and the last node to be visited.
|
|
*
|
|
* While this function requires cgroup_mutex or RCU read locking, it
|
|
* doesn't require the whole traversal to be contained in a single critical
|
|
* section. This function will return the correct next descendant as long
|
|
* as both @pos and @cgroup are accessible and @pos is a descendant of
|
|
* @cgroup.
|
|
*
|
|
* If a subsystem synchronizes ->css_online() and the start of iteration, a
|
|
* css which finished ->css_online() is guaranteed to be visible in the
|
|
* future iterations and will stay visible until the last reference is put.
|
|
* A css which hasn't finished ->css_online() or already finished
|
|
* ->css_offline() may show up during traversal. It's each subsystem's
|
|
* responsibility to synchronize against on/offlining.
|
|
*/
|
|
struct cgroup_subsys_state *
|
|
css_next_descendant_post(struct cgroup_subsys_state *pos,
|
|
struct cgroup_subsys_state *root)
|
|
{
|
|
struct cgroup_subsys_state *next;
|
|
|
|
cgroup_assert_mutex_or_rcu_locked();
|
|
|
|
/* if first iteration, visit leftmost descendant which may be @root */
|
|
if (!pos)
|
|
return css_leftmost_descendant(root);
|
|
|
|
/* if we visited @root, we're done */
|
|
if (pos == root)
|
|
return NULL;
|
|
|
|
/* if there's an unvisited sibling, visit its leftmost descendant */
|
|
next = css_next_child(pos, pos->parent);
|
|
if (next)
|
|
return css_leftmost_descendant(next);
|
|
|
|
/* no sibling left, visit parent */
|
|
return pos->parent;
|
|
}
|
|
|
|
/**
|
|
* css_has_online_children - does a css have online children
|
|
* @css: the target css
|
|
*
|
|
* Returns %true if @css has any online children; otherwise, %false. This
|
|
* function can be called from any context but the caller is responsible
|
|
* for synchronizing against on/offlining as necessary.
|
|
*/
|
|
bool css_has_online_children(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup_subsys_state *child;
|
|
bool ret = false;
|
|
|
|
rcu_read_lock();
|
|
css_for_each_child(child, css) {
|
|
if (child->flags & CSS_ONLINE) {
|
|
ret = true;
|
|
break;
|
|
}
|
|
}
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
static struct css_set *css_task_iter_next_css_set(struct css_task_iter *it)
|
|
{
|
|
struct list_head *l;
|
|
struct cgrp_cset_link *link;
|
|
struct css_set *cset;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
/* find the next threaded cset */
|
|
if (it->tcset_pos) {
|
|
l = it->tcset_pos->next;
|
|
|
|
if (l != it->tcset_head) {
|
|
it->tcset_pos = l;
|
|
return container_of(l, struct css_set,
|
|
threaded_csets_node);
|
|
}
|
|
|
|
it->tcset_pos = NULL;
|
|
}
|
|
|
|
/* find the next cset */
|
|
l = it->cset_pos;
|
|
l = l->next;
|
|
if (l == it->cset_head) {
|
|
it->cset_pos = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
if (it->ss) {
|
|
cset = container_of(l, struct css_set, e_cset_node[it->ss->id]);
|
|
} else {
|
|
link = list_entry(l, struct cgrp_cset_link, cset_link);
|
|
cset = link->cset;
|
|
}
|
|
|
|
it->cset_pos = l;
|
|
|
|
/* initialize threaded css_set walking */
|
|
if (it->flags & CSS_TASK_ITER_THREADED) {
|
|
if (it->cur_dcset)
|
|
put_css_set_locked(it->cur_dcset);
|
|
it->cur_dcset = cset;
|
|
get_css_set(cset);
|
|
|
|
it->tcset_head = &cset->threaded_csets;
|
|
it->tcset_pos = &cset->threaded_csets;
|
|
}
|
|
|
|
return cset;
|
|
}
|
|
|
|
/**
|
|
* css_task_iter_advance_css_set - advance a task itererator to the next css_set
|
|
* @it: the iterator to advance
|
|
*
|
|
* Advance @it to the next css_set to walk.
|
|
*/
|
|
static void css_task_iter_advance_css_set(struct css_task_iter *it)
|
|
{
|
|
struct css_set *cset;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
/* Advance to the next non-empty css_set */
|
|
do {
|
|
cset = css_task_iter_next_css_set(it);
|
|
if (!cset) {
|
|
it->task_pos = NULL;
|
|
return;
|
|
}
|
|
} while (!css_set_populated(cset) && list_empty(&cset->dying_tasks));
|
|
|
|
if (!list_empty(&cset->tasks)) {
|
|
it->task_pos = cset->tasks.next;
|
|
it->cur_tasks_head = &cset->tasks;
|
|
} else if (!list_empty(&cset->mg_tasks)) {
|
|
it->task_pos = cset->mg_tasks.next;
|
|
it->cur_tasks_head = &cset->mg_tasks;
|
|
} else {
|
|
it->task_pos = cset->dying_tasks.next;
|
|
it->cur_tasks_head = &cset->dying_tasks;
|
|
}
|
|
|
|
it->tasks_head = &cset->tasks;
|
|
it->mg_tasks_head = &cset->mg_tasks;
|
|
it->dying_tasks_head = &cset->dying_tasks;
|
|
|
|
/*
|
|
* We don't keep css_sets locked across iteration steps and thus
|
|
* need to take steps to ensure that iteration can be resumed after
|
|
* the lock is re-acquired. Iteration is performed at two levels -
|
|
* css_sets and tasks in them.
|
|
*
|
|
* Once created, a css_set never leaves its cgroup lists, so a
|
|
* pinned css_set is guaranteed to stay put and we can resume
|
|
* iteration afterwards.
|
|
*
|
|
* Tasks may leave @cset across iteration steps. This is resolved
|
|
* by registering each iterator with the css_set currently being
|
|
* walked and making css_set_move_task() advance iterators whose
|
|
* next task is leaving.
|
|
*/
|
|
if (it->cur_cset) {
|
|
list_del(&it->iters_node);
|
|
put_css_set_locked(it->cur_cset);
|
|
}
|
|
get_css_set(cset);
|
|
it->cur_cset = cset;
|
|
list_add(&it->iters_node, &cset->task_iters);
|
|
}
|
|
|
|
static void css_task_iter_skip(struct css_task_iter *it,
|
|
struct task_struct *task)
|
|
{
|
|
lockdep_assert_held(&css_set_lock);
|
|
|
|
if (it->task_pos == &task->cg_list) {
|
|
it->task_pos = it->task_pos->next;
|
|
it->flags |= CSS_TASK_ITER_SKIPPED;
|
|
}
|
|
}
|
|
|
|
static void css_task_iter_advance(struct css_task_iter *it)
|
|
{
|
|
struct task_struct *task;
|
|
|
|
lockdep_assert_held(&css_set_lock);
|
|
repeat:
|
|
if (it->task_pos) {
|
|
/*
|
|
* Advance iterator to find next entry. cset->tasks is
|
|
* consumed first and then ->mg_tasks. After ->mg_tasks,
|
|
* we move onto the next cset.
|
|
*/
|
|
if (it->flags & CSS_TASK_ITER_SKIPPED)
|
|
it->flags &= ~CSS_TASK_ITER_SKIPPED;
|
|
else
|
|
it->task_pos = it->task_pos->next;
|
|
|
|
if (it->task_pos == it->tasks_head) {
|
|
it->task_pos = it->mg_tasks_head->next;
|
|
it->cur_tasks_head = it->mg_tasks_head;
|
|
}
|
|
if (it->task_pos == it->mg_tasks_head) {
|
|
it->task_pos = it->dying_tasks_head->next;
|
|
it->cur_tasks_head = it->dying_tasks_head;
|
|
}
|
|
if (it->task_pos == it->dying_tasks_head)
|
|
css_task_iter_advance_css_set(it);
|
|
} else {
|
|
/* called from start, proceed to the first cset */
|
|
css_task_iter_advance_css_set(it);
|
|
}
|
|
|
|
if (!it->task_pos)
|
|
return;
|
|
|
|
task = list_entry(it->task_pos, struct task_struct, cg_list);
|
|
|
|
if (it->flags & CSS_TASK_ITER_PROCS) {
|
|
/* if PROCS, skip over tasks which aren't group leaders */
|
|
if (!thread_group_leader(task))
|
|
goto repeat;
|
|
|
|
/* and dying leaders w/o live member threads */
|
|
if (it->cur_tasks_head == it->dying_tasks_head &&
|
|
!atomic_read(&task->signal->live))
|
|
goto repeat;
|
|
} else {
|
|
/* skip all dying ones */
|
|
if (it->cur_tasks_head == it->dying_tasks_head)
|
|
goto repeat;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* css_task_iter_start - initiate task iteration
|
|
* @css: the css to walk tasks of
|
|
* @flags: CSS_TASK_ITER_* flags
|
|
* @it: the task iterator to use
|
|
*
|
|
* Initiate iteration through the tasks of @css. The caller can call
|
|
* css_task_iter_next() to walk through the tasks until the function
|
|
* returns NULL. On completion of iteration, css_task_iter_end() must be
|
|
* called.
|
|
*/
|
|
void css_task_iter_start(struct cgroup_subsys_state *css, unsigned int flags,
|
|
struct css_task_iter *it)
|
|
{
|
|
/* no one should try to iterate before mounting cgroups */
|
|
WARN_ON_ONCE(!use_task_css_set_links);
|
|
|
|
memset(it, 0, sizeof(*it));
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
it->ss = css->ss;
|
|
it->flags = flags;
|
|
|
|
if (it->ss)
|
|
it->cset_pos = &css->cgroup->e_csets[css->ss->id];
|
|
else
|
|
it->cset_pos = &css->cgroup->cset_links;
|
|
|
|
it->cset_head = it->cset_pos;
|
|
|
|
css_task_iter_advance(it);
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
}
|
|
|
|
/**
|
|
* css_task_iter_next - return the next task for the iterator
|
|
* @it: the task iterator being iterated
|
|
*
|
|
* The "next" function for task iteration. @it should have been
|
|
* initialized via css_task_iter_start(). Returns NULL when the iteration
|
|
* reaches the end.
|
|
*/
|
|
struct task_struct *css_task_iter_next(struct css_task_iter *it)
|
|
{
|
|
if (it->cur_task) {
|
|
put_task_struct(it->cur_task);
|
|
it->cur_task = NULL;
|
|
}
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
/* @it may be half-advanced by skips, finish advancing */
|
|
if (it->flags & CSS_TASK_ITER_SKIPPED)
|
|
css_task_iter_advance(it);
|
|
|
|
if (it->task_pos) {
|
|
it->cur_task = list_entry(it->task_pos, struct task_struct,
|
|
cg_list);
|
|
get_task_struct(it->cur_task);
|
|
css_task_iter_advance(it);
|
|
}
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
return it->cur_task;
|
|
}
|
|
|
|
/**
|
|
* css_task_iter_end - finish task iteration
|
|
* @it: the task iterator to finish
|
|
*
|
|
* Finish task iteration started by css_task_iter_start().
|
|
*/
|
|
void css_task_iter_end(struct css_task_iter *it)
|
|
{
|
|
if (it->cur_cset) {
|
|
spin_lock_irq(&css_set_lock);
|
|
list_del(&it->iters_node);
|
|
put_css_set_locked(it->cur_cset);
|
|
spin_unlock_irq(&css_set_lock);
|
|
}
|
|
|
|
if (it->cur_dcset)
|
|
put_css_set(it->cur_dcset);
|
|
|
|
if (it->cur_task)
|
|
put_task_struct(it->cur_task);
|
|
}
|
|
|
|
static void cgroup_procs_release(struct kernfs_open_file *of)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
|
|
if (ctx->procs.started)
|
|
css_task_iter_end(&ctx->procs.iter);
|
|
}
|
|
|
|
static void *cgroup_procs_next(struct seq_file *s, void *v, loff_t *pos)
|
|
{
|
|
struct kernfs_open_file *of = s->private;
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
|
|
if (pos)
|
|
(*pos)++;
|
|
|
|
return css_task_iter_next(&ctx->procs.iter);
|
|
}
|
|
|
|
static void *__cgroup_procs_start(struct seq_file *s, loff_t *pos,
|
|
unsigned int iter_flags)
|
|
{
|
|
struct kernfs_open_file *of = s->private;
|
|
struct cgroup *cgrp = seq_css(s)->cgroup;
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
struct css_task_iter *it = &ctx->procs.iter;
|
|
|
|
/*
|
|
* When a seq_file is seeked, it's always traversed sequentially
|
|
* from position 0, so we can simply keep iterating on !0 *pos.
|
|
*/
|
|
if (!ctx->procs.started) {
|
|
if (WARN_ON_ONCE((*pos)))
|
|
return ERR_PTR(-EINVAL);
|
|
css_task_iter_start(&cgrp->self, iter_flags, it);
|
|
ctx->procs.started = true;
|
|
} else if (!(*pos)) {
|
|
css_task_iter_end(it);
|
|
css_task_iter_start(&cgrp->self, iter_flags, it);
|
|
} else
|
|
return it->cur_task;
|
|
|
|
return cgroup_procs_next(s, NULL, NULL);
|
|
}
|
|
|
|
static void *cgroup_procs_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
struct cgroup *cgrp = seq_css(s)->cgroup;
|
|
|
|
/*
|
|
* All processes of a threaded subtree belong to the domain cgroup
|
|
* of the subtree. Only threads can be distributed across the
|
|
* subtree. Reject reads on cgroup.procs in the subtree proper.
|
|
* They're always empty anyway.
|
|
*/
|
|
if (cgroup_is_threaded(cgrp))
|
|
return ERR_PTR(-EOPNOTSUPP);
|
|
|
|
return __cgroup_procs_start(s, pos, CSS_TASK_ITER_PROCS |
|
|
CSS_TASK_ITER_THREADED);
|
|
}
|
|
|
|
static int cgroup_procs_show(struct seq_file *s, void *v)
|
|
{
|
|
seq_printf(s, "%d\n", task_pid_vnr(v));
|
|
return 0;
|
|
}
|
|
|
|
static int cgroup_procs_write_permission(struct cgroup *src_cgrp,
|
|
struct cgroup *dst_cgrp,
|
|
struct super_block *sb,
|
|
struct cgroup_namespace *ns)
|
|
{
|
|
struct cgroup *com_cgrp = src_cgrp;
|
|
struct inode *inode;
|
|
int ret;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/* find the common ancestor */
|
|
while (!cgroup_is_descendant(dst_cgrp, com_cgrp))
|
|
com_cgrp = cgroup_parent(com_cgrp);
|
|
|
|
/* %current should be authorized to migrate to the common ancestor */
|
|
inode = kernfs_get_inode(sb, com_cgrp->procs_file.kn);
|
|
if (!inode)
|
|
return -ENOMEM;
|
|
|
|
ret = inode_permission(inode, MAY_WRITE);
|
|
iput(inode);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/*
|
|
* If namespaces are delegation boundaries, %current must be able
|
|
* to see both source and destination cgroups from its namespace.
|
|
*/
|
|
if ((cgrp_dfl_root.flags & CGRP_ROOT_NS_DELEGATE) &&
|
|
(!cgroup_is_descendant(src_cgrp, ns->root_cset->dfl_cgrp) ||
|
|
!cgroup_is_descendant(dst_cgrp, ns->root_cset->dfl_cgrp)))
|
|
return -ENOENT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t cgroup_procs_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
struct cgroup *src_cgrp, *dst_cgrp;
|
|
struct task_struct *task;
|
|
const struct cred *saved_cred;
|
|
ssize_t ret;
|
|
bool threadgroup_locked;
|
|
|
|
dst_cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!dst_cgrp)
|
|
return -ENODEV;
|
|
|
|
task = cgroup_procs_write_start(buf, true, &threadgroup_locked);
|
|
ret = PTR_ERR_OR_ZERO(task);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
/* find the source cgroup */
|
|
spin_lock_irq(&css_set_lock);
|
|
src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/*
|
|
* Process and thread migrations follow same delegation rule. Check
|
|
* permissions using the credentials from file open to protect against
|
|
* inherited fd attacks.
|
|
*/
|
|
saved_cred = override_creds(of->file->f_cred);
|
|
ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp,
|
|
of->file->f_path.dentry->d_sb,
|
|
ctx->ns);
|
|
revert_creds(saved_cred);
|
|
if (ret)
|
|
goto out_finish;
|
|
|
|
ret = cgroup_attach_task(dst_cgrp, task, true);
|
|
|
|
out_finish:
|
|
cgroup_procs_write_finish(task, threadgroup_locked);
|
|
out_unlock:
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
static void *cgroup_threads_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
return __cgroup_procs_start(s, pos, 0);
|
|
}
|
|
|
|
static ssize_t cgroup_threads_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup_file_ctx *ctx = of->priv;
|
|
struct cgroup *src_cgrp, *dst_cgrp;
|
|
struct task_struct *task;
|
|
const struct cred *saved_cred;
|
|
ssize_t ret;
|
|
bool locked;
|
|
|
|
buf = strstrip(buf);
|
|
|
|
dst_cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!dst_cgrp)
|
|
return -ENODEV;
|
|
|
|
task = cgroup_procs_write_start(buf, false, &locked);
|
|
ret = PTR_ERR_OR_ZERO(task);
|
|
if (ret)
|
|
goto out_unlock;
|
|
|
|
/* find the source cgroup */
|
|
spin_lock_irq(&css_set_lock);
|
|
src_cgrp = task_cgroup_from_root(task, &cgrp_dfl_root);
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/*
|
|
* Process and thread migrations follow same delegation rule. Check
|
|
* permissions using the credentials from file open to protect against
|
|
* inherited fd attacks.
|
|
*/
|
|
saved_cred = override_creds(of->file->f_cred);
|
|
ret = cgroup_procs_write_permission(src_cgrp, dst_cgrp,
|
|
of->file->f_path.dentry->d_sb,
|
|
ctx->ns);
|
|
revert_creds(saved_cred);
|
|
if (ret)
|
|
goto out_finish;
|
|
|
|
/* and must be contained in the same domain */
|
|
ret = -EOPNOTSUPP;
|
|
if (src_cgrp->dom_cgrp != dst_cgrp->dom_cgrp)
|
|
goto out_finish;
|
|
|
|
ret = cgroup_attach_task(dst_cgrp, task, false);
|
|
|
|
out_finish:
|
|
cgroup_procs_write_finish(task, locked);
|
|
out_unlock:
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
#ifdef CONFIG_CGROUPFS
|
|
int cgroup_role_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
u16 role = cgrp->role;
|
|
|
|
seq_printf(seq, "%d\n", role);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static void cgroup_role_propagate(struct cgroup *cgrp, u16 type)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
|
|
dsct->role = type;
|
|
}
|
|
}
|
|
|
|
ssize_t cgroup_role_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup *cgrp;
|
|
ssize_t ret;
|
|
u16 role, old;
|
|
|
|
buf = strstrip(buf);
|
|
ret = kstrtou16(buf, 0, &role);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (role < 0 || role > CGROUPFS_CGROUP_ROLE_POD_GROUPS)
|
|
return -ERANGE;
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!cgrp)
|
|
return -ENOENT;
|
|
|
|
old = cgrp->role;
|
|
if (role == old)
|
|
goto unlock_out;
|
|
|
|
cgrp->role = role;
|
|
cgroup_role_propagate(cgrp, role);
|
|
|
|
unlock_out:
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
struct cgroup_subsys_state *cgroupfs_get_parent_role_cgroup(
|
|
struct task_struct *task, int type, int cgrp_id)
|
|
{
|
|
struct cgroup_subsys_state *css, *prev_css, *orig_css;
|
|
|
|
css = task_get_css(task, cgrp_id);
|
|
prev_css = orig_css = css;
|
|
|
|
while (css && css->cgroup->role == type) {
|
|
prev_css = css;
|
|
css = css->parent;
|
|
}
|
|
|
|
if (prev_css != orig_css) {
|
|
css_get(prev_css);
|
|
css_put(orig_css);
|
|
}
|
|
|
|
return prev_css;
|
|
}
|
|
|
|
#else
|
|
struct cgroup_subsys_state *cgroupfs_get_parent_role_cgroup(
|
|
struct task_struct *task, int type, int cgrp_id)
|
|
{
|
|
return task_get_css(task, cgrp_id);
|
|
}
|
|
|
|
#endif
|
|
|
|
int cgroup_priority_show(struct seq_file *seq, void *v)
|
|
{
|
|
struct cgroup *cgrp = seq_css(seq)->cgroup;
|
|
unsigned int prio = cgrp->priority;
|
|
|
|
seq_printf(seq, "%d\n", prio);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void cgroup_set_priority(struct cgroup *cgrp, u16 priority)
|
|
{
|
|
u16 old = cgrp->priority;
|
|
struct cgroup_subsys_state *css;
|
|
int ssid;
|
|
|
|
cgrp->priority = priority;
|
|
|
|
for_each_css(css, ssid, cgrp) {
|
|
if (css->ss->css_priority_change)
|
|
css->ss->css_priority_change(css, old, priority);
|
|
}
|
|
}
|
|
|
|
static void cgroup_priority_propagate(struct cgroup *cgrp)
|
|
{
|
|
struct cgroup *dsct;
|
|
struct cgroup_subsys_state *d_css;
|
|
u16 priority = cgrp->priority;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
cgroup_for_each_live_descendant_pre(dsct, d_css, cgrp) {
|
|
cgroup_set_priority(dsct, priority);
|
|
}
|
|
}
|
|
|
|
ssize_t cgroup_priority_write(struct kernfs_open_file *of,
|
|
char *buf, size_t nbytes, loff_t off)
|
|
{
|
|
struct cgroup *cgrp, *parent;
|
|
ssize_t ret;
|
|
u16 prio, old;
|
|
|
|
buf = strstrip(buf);
|
|
ret = kstrtou16(buf, 0, &prio);
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (prio < 0 || prio >= CGROUP_PRIORITY_MAX)
|
|
return -ERANGE;
|
|
|
|
cgrp = cgroup_kn_lock_live(of->kn, false);
|
|
if (!cgrp)
|
|
return -ENOENT;
|
|
parent = cgroup_parent(cgrp);
|
|
if (parent && parent->priority && prio != parent->priority) {
|
|
ret = -EINVAL;
|
|
goto unlock_out;
|
|
}
|
|
|
|
old = cgrp->priority;
|
|
if (prio == old)
|
|
goto unlock_out;
|
|
cgroup_set_priority(cgrp, prio);
|
|
if (prio > old)
|
|
cgroup_priority_propagate(cgrp);
|
|
unlock_out:
|
|
cgroup_kn_unlock(of->kn);
|
|
|
|
return ret ?: nbytes;
|
|
}
|
|
|
|
ssize_t cgroup_priority(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup *cgrp = css->cgroup;
|
|
unsigned int prio = 0;
|
|
|
|
if (cgrp)
|
|
prio = cgrp->priority;
|
|
return prio;
|
|
}
|
|
EXPORT_SYMBOL(cgroup_priority);
|
|
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
int cgroup_sli_monitor_open(struct kernfs_open_file *of)
|
|
{
|
|
return sli_monitor_open(of);
|
|
}
|
|
|
|
void *cgroup_sli_monitor_start(struct seq_file *s, loff_t *pos)
|
|
{
|
|
return sli_monitor_start(s, pos);
|
|
}
|
|
|
|
int cgroup_sli_monitor_show(struct seq_file *seq, void *v)
|
|
{
|
|
return sli_monitor_show(seq, v);
|
|
}
|
|
|
|
void *cgroup_sli_monitor_next(struct seq_file *s, void *v, loff_t *pos)
|
|
{
|
|
return sli_monitor_next(s, v, pos);
|
|
}
|
|
|
|
void cgroup_sli_monitor_stop(struct seq_file *seq, void *v)
|
|
{
|
|
sli_monitor_stop(seq, v);
|
|
}
|
|
|
|
__poll_t cgroup_sli_monitor_poll(struct kernfs_open_file *of, poll_table *pt)
|
|
{
|
|
return sli_monitor_poll(of, pt);
|
|
}
|
|
#endif
|
|
|
|
/* cgroup core interface files for the default hierarchy */
|
|
static struct cftype cgroup_base_files[] = {
|
|
{
|
|
.name = "cgroup.type",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_type_show,
|
|
.write = cgroup_type_write,
|
|
},
|
|
{
|
|
.name = "cgroup.id",
|
|
.seq_show = cgroup_id_show,
|
|
},
|
|
{
|
|
.name = "cgroup.procs",
|
|
.flags = CFTYPE_NS_DELEGATABLE,
|
|
.file_offset = offsetof(struct cgroup, procs_file),
|
|
.release = cgroup_procs_release,
|
|
.seq_start = cgroup_procs_start,
|
|
.seq_next = cgroup_procs_next,
|
|
.seq_show = cgroup_procs_show,
|
|
.write = cgroup_procs_write,
|
|
},
|
|
{
|
|
.name = "cgroup.threads",
|
|
.flags = CFTYPE_NS_DELEGATABLE,
|
|
.release = cgroup_procs_release,
|
|
.seq_start = cgroup_threads_start,
|
|
.seq_next = cgroup_procs_next,
|
|
.seq_show = cgroup_procs_show,
|
|
.write = cgroup_threads_write,
|
|
},
|
|
{
|
|
.name = "cgroup.controllers",
|
|
.seq_show = cgroup_controllers_show,
|
|
},
|
|
{
|
|
.name = "cgroup.subtree_control",
|
|
.flags = CFTYPE_NS_DELEGATABLE,
|
|
.seq_show = cgroup_subtree_control_show,
|
|
.write = cgroup_subtree_control_write,
|
|
},
|
|
{
|
|
.name = "cgroup.events",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.file_offset = offsetof(struct cgroup, events_file),
|
|
.seq_show = cgroup_events_show,
|
|
},
|
|
{
|
|
.name = "cgroup.max.descendants",
|
|
.seq_show = cgroup_max_descendants_show,
|
|
.write = cgroup_max_descendants_write,
|
|
},
|
|
{
|
|
.name = "cgroup.max.depth",
|
|
.seq_show = cgroup_max_depth_show,
|
|
.write = cgroup_max_depth_write,
|
|
},
|
|
{
|
|
.name = "cgroup.priority",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_priority_show,
|
|
.write = cgroup_priority_write,
|
|
},
|
|
{
|
|
.name = "cgroup.stat",
|
|
.seq_show = cgroup_stat_show,
|
|
},
|
|
{
|
|
.name = "cgroup.freeze",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_freeze_show,
|
|
.write = cgroup_freeze_write,
|
|
},
|
|
{
|
|
.name = "cpu.stat",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cpu_stat_show,
|
|
},
|
|
#ifdef CONFIG_PSI
|
|
{
|
|
.name = "io.pressure",
|
|
.seq_show = cgroup_io_pressure_show,
|
|
.write = cgroup_io_pressure_write,
|
|
.poll = cgroup_pressure_poll,
|
|
.release = cgroup_pressure_release,
|
|
},
|
|
{
|
|
.name = "memory.pressure",
|
|
.seq_show = cgroup_memory_pressure_show,
|
|
.write = cgroup_memory_pressure_write,
|
|
.poll = cgroup_pressure_poll,
|
|
.release = cgroup_pressure_release,
|
|
},
|
|
{
|
|
.name = "cpu.pressure",
|
|
.seq_show = cgroup_cpu_pressure_show,
|
|
.write = cgroup_cpu_pressure_write,
|
|
.poll = cgroup_pressure_poll,
|
|
.release = cgroup_pressure_release,
|
|
},
|
|
#endif /* CONFIG_PSI */
|
|
#ifdef CONFIG_RQM
|
|
{
|
|
.name = "io.quality",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_io_quality_show,
|
|
.release = cgroup_quality_release,
|
|
},
|
|
{
|
|
.name = "memory.quality",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_mem_quality_show,
|
|
.release = cgroup_mem_release,
|
|
},
|
|
{
|
|
.name = "cpu.quality",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_cpu_quality_show,
|
|
.release = cgroup_cpu_release,
|
|
},
|
|
{
|
|
.name = "net.quality",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_net_quality_show,
|
|
.release = cgroup_net_release,
|
|
},
|
|
#endif
|
|
{
|
|
.name = "mbuf",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_mbuf_show,
|
|
.seq_start = cgroup_mbuf_start,
|
|
.seq_next = cgroup_mbuf_next,
|
|
.seq_stop = cgroup_mbuf_stop,
|
|
},
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
{
|
|
.name = "sli.memory",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_sli_memory_show,
|
|
},
|
|
{
|
|
.name = "sli.cpu",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_sli_cpu_show,
|
|
},
|
|
{
|
|
.name = "sli.max",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.seq_show = cgroup_sli_max_show,
|
|
},
|
|
{
|
|
.name = "sli.control",
|
|
.write = cgroup_sli_control_write,
|
|
.seq_show = cgroup_sli_control_show,
|
|
},
|
|
{
|
|
.name = "sli.monitor",
|
|
.flags = CFTYPE_NOT_ON_ROOT,
|
|
.open = cgroup_sli_monitor_open,
|
|
.seq_show = cgroup_sli_monitor_show,
|
|
.seq_start = cgroup_sli_monitor_start,
|
|
.seq_next = cgroup_sli_monitor_next,
|
|
.seq_stop = cgroup_sli_monitor_stop,
|
|
.poll = cgroup_sli_monitor_poll,
|
|
},
|
|
#endif
|
|
{ } /* terminate */
|
|
};
|
|
|
|
/*
|
|
* css destruction is four-stage process.
|
|
*
|
|
* 1. Destruction starts. Killing of the percpu_ref is initiated.
|
|
* Implemented in kill_css().
|
|
*
|
|
* 2. When the percpu_ref is confirmed to be visible as killed on all CPUs
|
|
* and thus css_tryget_online() is guaranteed to fail, the css can be
|
|
* offlined by invoking offline_css(). After offlining, the base ref is
|
|
* put. Implemented in css_killed_work_fn().
|
|
*
|
|
* 3. When the percpu_ref reaches zero, the only possible remaining
|
|
* accessors are inside RCU read sections. css_release() schedules the
|
|
* RCU callback.
|
|
*
|
|
* 4. After the grace period, the css can be freed. Implemented in
|
|
* css_free_work_fn().
|
|
*
|
|
* It is actually hairier because both step 2 and 4 require process context
|
|
* and thus involve punting to css->destroy_work adding two additional
|
|
* steps to the already complex sequence.
|
|
*/
|
|
static void css_free_rwork_fn(struct work_struct *work)
|
|
{
|
|
struct cgroup_subsys_state *css = container_of(to_rcu_work(work),
|
|
struct cgroup_subsys_state, destroy_rwork);
|
|
struct cgroup_subsys *ss = css->ss;
|
|
struct cgroup *cgrp = css->cgroup;
|
|
|
|
percpu_ref_exit(&css->refcnt);
|
|
|
|
if (ss) {
|
|
/* css free path */
|
|
struct cgroup_subsys_state *parent = css->parent;
|
|
int id = css->id;
|
|
|
|
ss->css_free(css);
|
|
cgroup_idr_remove(&ss->css_idr, id);
|
|
cgroup_put(cgrp);
|
|
|
|
if (parent)
|
|
css_put(parent);
|
|
} else {
|
|
/* cgroup free path */
|
|
atomic_dec(&cgrp->root->nr_cgrps);
|
|
cgroup1_pidlist_destroy_all(cgrp);
|
|
cancel_work_sync(&cgrp->release_agent_work);
|
|
|
|
if (cgroup_parent(cgrp)) {
|
|
/*
|
|
* We get a ref to the parent, and put the ref when
|
|
* this cgroup is being freed, so it's guaranteed
|
|
* that the parent won't be destroyed before its
|
|
* children.
|
|
*/
|
|
cgroup_put(cgroup_parent(cgrp));
|
|
kernfs_put(cgrp->kn);
|
|
psi_cgroup_free(cgrp);
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
sli_cgroup_free(cgrp);
|
|
#endif
|
|
if (cgroup_on_dfl(cgrp))
|
|
cgroup_rstat_exit(cgrp);
|
|
kfree(cgrp);
|
|
} else {
|
|
/*
|
|
* This is root cgroup's refcnt reaching zero,
|
|
* which indicates that the root should be
|
|
* released.
|
|
*/
|
|
cgroup_destroy_root(cgrp->root);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void css_release_work_fn(struct work_struct *work)
|
|
{
|
|
struct cgroup_subsys_state *css =
|
|
container_of(work, struct cgroup_subsys_state, destroy_work);
|
|
struct cgroup_subsys *ss = css->ss;
|
|
struct cgroup *cgrp = css->cgroup;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
css->flags |= CSS_RELEASED;
|
|
list_del_rcu(&css->sibling);
|
|
|
|
if (ss) {
|
|
/* css release path */
|
|
if (!list_empty(&css->rstat_css_node)) {
|
|
cgroup_rstat_flush(cgrp);
|
|
list_del_rcu(&css->rstat_css_node);
|
|
}
|
|
|
|
cgroup_idr_replace(&ss->css_idr, NULL, css->id);
|
|
if (ss->css_released)
|
|
ss->css_released(css);
|
|
} else {
|
|
struct cgroup *tcgrp;
|
|
|
|
/* cgroup release path */
|
|
TRACE_CGROUP_PATH(release, cgrp);
|
|
|
|
if (cgroup_on_dfl(cgrp))
|
|
cgroup_rstat_flush(cgrp);
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
for (tcgrp = cgroup_parent(cgrp); tcgrp;
|
|
tcgrp = cgroup_parent(tcgrp))
|
|
tcgrp->nr_dying_descendants--;
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
cgroup_idr_remove(&cgrp->root->cgroup_idr, cgrp->id);
|
|
cgrp->id = -1;
|
|
|
|
/*
|
|
* There are two control paths which try to determine
|
|
* cgroup from dentry without going through kernfs -
|
|
* cgroupstats_build() and css_tryget_online_from_dir().
|
|
* Those are supported by RCU protecting clearing of
|
|
* cgrp->kn->priv backpointer.
|
|
*/
|
|
if (cgrp->kn)
|
|
RCU_INIT_POINTER(*(void __rcu __force **)&cgrp->kn->priv,
|
|
NULL);
|
|
}
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
|
|
INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
|
|
queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
|
|
}
|
|
|
|
static void css_release(struct percpu_ref *ref)
|
|
{
|
|
struct cgroup_subsys_state *css =
|
|
container_of(ref, struct cgroup_subsys_state, refcnt);
|
|
|
|
INIT_WORK(&css->destroy_work, css_release_work_fn);
|
|
queue_work(cgroup_destroy_wq, &css->destroy_work);
|
|
}
|
|
|
|
static void init_and_link_css(struct cgroup_subsys_state *css,
|
|
struct cgroup_subsys *ss, struct cgroup *cgrp)
|
|
{
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
cgroup_get_live(cgrp);
|
|
|
|
memset(css, 0, sizeof(*css));
|
|
css->cgroup = cgrp;
|
|
css->ss = ss;
|
|
css->id = -1;
|
|
INIT_LIST_HEAD(&css->sibling);
|
|
INIT_LIST_HEAD(&css->children);
|
|
INIT_LIST_HEAD(&css->rstat_css_node);
|
|
css->serial_nr = css_serial_nr_next++;
|
|
atomic_set(&css->online_cnt, 0);
|
|
|
|
if (cgroup_parent(cgrp)) {
|
|
css->parent = cgroup_css(cgroup_parent(cgrp), ss);
|
|
css_get(css->parent);
|
|
}
|
|
|
|
if (cgroup_on_dfl(cgrp) && ss->css_rstat_flush)
|
|
list_add_rcu(&css->rstat_css_node, &cgrp->rstat_css_list);
|
|
|
|
BUG_ON(cgroup_css(cgrp, ss));
|
|
}
|
|
|
|
/* invoke ->css_online() on a new CSS and mark it online if successful */
|
|
static int online_css(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup_subsys *ss = css->ss;
|
|
int ret = 0;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
if (ss->css_online)
|
|
ret = ss->css_online(css);
|
|
if (!ret) {
|
|
css->flags |= CSS_ONLINE;
|
|
rcu_assign_pointer(css->cgroup->subsys[ss->id], css);
|
|
|
|
atomic_inc(&css->online_cnt);
|
|
if (css->parent)
|
|
atomic_inc(&css->parent->online_cnt);
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
/* if the CSS is online, invoke ->css_offline() on it and mark it offline */
|
|
static void offline_css(struct cgroup_subsys_state *css)
|
|
{
|
|
struct cgroup_subsys *ss = css->ss;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
if (!(css->flags & CSS_ONLINE))
|
|
return;
|
|
|
|
if (ss->css_offline)
|
|
ss->css_offline(css);
|
|
|
|
css->flags &= ~CSS_ONLINE;
|
|
RCU_INIT_POINTER(css->cgroup->subsys[ss->id], NULL);
|
|
|
|
wake_up_all(&css->cgroup->offline_waitq);
|
|
}
|
|
|
|
/**
|
|
* css_create - create a cgroup_subsys_state
|
|
* @cgrp: the cgroup new css will be associated with
|
|
* @ss: the subsys of new css
|
|
*
|
|
* Create a new css associated with @cgrp - @ss pair. On success, the new
|
|
* css is online and installed in @cgrp. This function doesn't create the
|
|
* interface files. Returns 0 on success, -errno on failure.
|
|
*/
|
|
static struct cgroup_subsys_state *css_create(struct cgroup *cgrp,
|
|
struct cgroup_subsys *ss)
|
|
{
|
|
struct cgroup *parent = cgroup_parent(cgrp);
|
|
struct cgroup_subsys_state *parent_css = cgroup_css(parent, ss);
|
|
struct cgroup_subsys_state *css;
|
|
int err;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
css = ss->css_alloc(parent_css);
|
|
if (!css)
|
|
css = ERR_PTR(-ENOMEM);
|
|
if (IS_ERR(css))
|
|
return css;
|
|
|
|
init_and_link_css(css, ss, cgrp);
|
|
|
|
err = percpu_ref_init(&css->refcnt, css_release, 0, GFP_KERNEL);
|
|
if (err)
|
|
goto err_free_css;
|
|
|
|
err = cgroup_idr_alloc(&ss->css_idr, NULL, 2, 0, GFP_KERNEL);
|
|
if (err < 0)
|
|
goto err_free_css;
|
|
css->id = err;
|
|
|
|
/* @css is ready to be brought online now, make it visible */
|
|
list_add_tail_rcu(&css->sibling, &parent_css->children);
|
|
cgroup_idr_replace(&ss->css_idr, css, css->id);
|
|
|
|
err = online_css(css);
|
|
if (err)
|
|
goto err_list_del;
|
|
|
|
if (ss->broken_hierarchy && !ss->warned_broken_hierarchy &&
|
|
cgroup_parent(parent)) {
|
|
pr_warn("%s (%d) created nested cgroup for controller \"%s\" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.\n",
|
|
current->comm, current->pid, ss->name);
|
|
if (!strcmp(ss->name, "memory"))
|
|
pr_warn("\"memory\" requires setting use_hierarchy to 1 on the root\n");
|
|
ss->warned_broken_hierarchy = true;
|
|
}
|
|
|
|
return css;
|
|
|
|
err_list_del:
|
|
list_del_rcu(&css->sibling);
|
|
err_free_css:
|
|
list_del_rcu(&css->rstat_css_node);
|
|
INIT_RCU_WORK(&css->destroy_rwork, css_free_rwork_fn);
|
|
queue_rcu_work(cgroup_destroy_wq, &css->destroy_rwork);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
/*
|
|
* The returned cgroup is fully initialized including its control mask, but
|
|
* it isn't associated with its kernfs_node and doesn't have the control
|
|
* mask applied.
|
|
*/
|
|
static struct cgroup *cgroup_create(struct cgroup *parent)
|
|
{
|
|
struct cgroup_root *root = parent->root;
|
|
struct cgroup *cgrp, *tcgrp;
|
|
int level = parent->level + 1;
|
|
int ret;
|
|
|
|
/* allocate the cgroup and its ID, 0 is reserved for the root */
|
|
cgrp = kzalloc(struct_size(cgrp, ancestor_ids, (level + 1)),
|
|
GFP_KERNEL);
|
|
if (!cgrp)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
ret = percpu_ref_init(&cgrp->self.refcnt, css_release, 0, GFP_KERNEL);
|
|
if (ret)
|
|
goto out_free_cgrp;
|
|
|
|
if (cgroup_on_dfl(parent)) {
|
|
ret = cgroup_rstat_init(cgrp);
|
|
if (ret)
|
|
goto out_cancel_ref;
|
|
}
|
|
|
|
/*
|
|
* Temporarily set the pointer to NULL, so idr_find() won't return
|
|
* a half-baked cgroup.
|
|
*/
|
|
cgrp->id = cgroup_idr_alloc(&root->cgroup_idr, NULL, 2, 0, GFP_KERNEL);
|
|
if (cgrp->id < 0) {
|
|
ret = -ENOMEM;
|
|
goto out_stat_exit;
|
|
}
|
|
|
|
init_cgroup_housekeeping(cgrp);
|
|
|
|
cgrp->self.parent = &parent->self;
|
|
cgrp->root = root;
|
|
cgrp->level = level;
|
|
cgrp->priority = parent->priority;
|
|
#ifdef CONFIG_CGROUPFS
|
|
cgrp->role = parent->role;
|
|
#endif
|
|
cgrp->mbuf = NULL;
|
|
|
|
ret = psi_cgroup_alloc(cgrp);
|
|
if (ret)
|
|
goto out_idr_free;
|
|
|
|
rqm_group_init(&cgrp->rqm);
|
|
|
|
ret = cgroup_bpf_inherit(cgrp);
|
|
if (ret)
|
|
goto out_psi_free;
|
|
|
|
/*
|
|
* New cgroup inherits effective freeze counter, and
|
|
* if the parent has to be frozen, the child has too.
|
|
*/
|
|
cgrp->freezer.e_freeze = parent->freezer.e_freeze;
|
|
if (cgrp->freezer.e_freeze) {
|
|
/*
|
|
* Set the CGRP_FREEZE flag, so when a process will be
|
|
* attached to the child cgroup, it will become frozen.
|
|
* At this point the new cgroup is unpopulated, so we can
|
|
* consider it frozen immediately.
|
|
*/
|
|
set_bit(CGRP_FREEZE, &cgrp->flags);
|
|
set_bit(CGRP_FROZEN, &cgrp->flags);
|
|
}
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
for (tcgrp = cgrp; tcgrp; tcgrp = cgroup_parent(tcgrp)) {
|
|
cgrp->ancestor_ids[tcgrp->level] = tcgrp->id;
|
|
|
|
if (tcgrp != cgrp) {
|
|
tcgrp->nr_descendants++;
|
|
|
|
/*
|
|
* If the new cgroup is frozen, all ancestor cgroups
|
|
* get a new frozen descendant, but their state can't
|
|
* change because of this.
|
|
*/
|
|
if (cgrp->freezer.e_freeze)
|
|
tcgrp->freezer.nr_frozen_descendants++;
|
|
}
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
if (notify_on_release(parent))
|
|
set_bit(CGRP_NOTIFY_ON_RELEASE, &cgrp->flags);
|
|
|
|
if (test_bit(CGRP_CPUSET_CLONE_CHILDREN, &parent->flags))
|
|
set_bit(CGRP_CPUSET_CLONE_CHILDREN, &cgrp->flags);
|
|
|
|
cgrp->self.serial_nr = css_serial_nr_next++;
|
|
|
|
/* allocation complete, commit to creation */
|
|
list_add_tail_rcu(&cgrp->self.sibling, &cgroup_parent(cgrp)->self.children);
|
|
atomic_inc(&root->nr_cgrps);
|
|
cgroup_get_live(parent);
|
|
|
|
/*
|
|
* @cgrp is now fully operational. If something fails after this
|
|
* point, it'll be released via the normal destruction path.
|
|
*/
|
|
cgroup_idr_replace(&root->cgroup_idr, cgrp, cgrp->id);
|
|
|
|
/*
|
|
* On the default hierarchy, a child doesn't automatically inherit
|
|
* subtree_control from the parent. Each is configured manually.
|
|
*/
|
|
if (!cgroup_on_dfl(cgrp))
|
|
cgrp->subtree_control = cgroup_control(cgrp);
|
|
|
|
cgroup_propagate_control(cgrp);
|
|
|
|
return cgrp;
|
|
out_psi_free:
|
|
psi_cgroup_free(cgrp);
|
|
out_idr_free:
|
|
cgroup_idr_remove(&root->cgroup_idr, cgrp->id);
|
|
out_stat_exit:
|
|
if (cgroup_on_dfl(parent))
|
|
cgroup_rstat_exit(cgrp);
|
|
out_cancel_ref:
|
|
percpu_ref_exit(&cgrp->self.refcnt);
|
|
out_free_cgrp:
|
|
kfree(cgrp);
|
|
return ERR_PTR(ret);
|
|
}
|
|
|
|
static bool cgroup_check_hierarchy_limits(struct cgroup *parent)
|
|
{
|
|
struct cgroup *cgroup;
|
|
int ret = false;
|
|
int level = 1;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
for (cgroup = parent; cgroup; cgroup = cgroup_parent(cgroup)) {
|
|
if (cgroup->nr_descendants >= cgroup->max_descendants)
|
|
goto fail;
|
|
|
|
if (level > cgroup->max_depth)
|
|
goto fail;
|
|
|
|
level++;
|
|
}
|
|
|
|
ret = true;
|
|
fail:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* mbuf only support cpu/memory/io/net cgroup in V2, and only support
|
|
* cpuacct cgroup in V1.
|
|
*/
|
|
static inline bool cgroup_need_mbuf(struct cgroup *cgrp)
|
|
{
|
|
if (cgroup_on_dfl(cgrp))
|
|
return true;
|
|
|
|
#if IS_ENABLED(CONFIG_CGROUP_CPUACCT)
|
|
if (cgroup_css(cgrp, cgroup_subsys[cpuacct_cgrp_id]))
|
|
return true;
|
|
#endif
|
|
|
|
#if IS_ENABLED(CONFIG_MEMCG)
|
|
if (cgroup_css(cgrp, cgroup_subsys[memory_cgrp_id]))
|
|
return true;
|
|
#endif
|
|
|
|
return false;
|
|
}
|
|
|
|
/* Wrap the mbuf and export to the include file */
|
|
bool cgroup_need_sli(struct cgroup *cgrp)
|
|
{
|
|
return cgroup_need_mbuf(cgrp);
|
|
}
|
|
|
|
int cgroup_mkdir(struct kernfs_node *parent_kn, const char *name, umode_t mode)
|
|
{
|
|
struct cgroup *parent, *cgrp;
|
|
struct kernfs_node *kn;
|
|
int ret;
|
|
|
|
/* do not accept '\n' to prevent making /proc/<pid>/cgroup unparsable */
|
|
if (strchr(name, '\n'))
|
|
return -EINVAL;
|
|
|
|
parent = cgroup_kn_lock_live(parent_kn, false);
|
|
if (!parent)
|
|
return -ENODEV;
|
|
|
|
if (!cgroup_check_hierarchy_limits(parent)) {
|
|
ret = -EAGAIN;
|
|
goto out_unlock;
|
|
}
|
|
|
|
cgrp = cgroup_create(parent);
|
|
if (IS_ERR(cgrp)) {
|
|
ret = PTR_ERR(cgrp);
|
|
goto out_unlock;
|
|
}
|
|
|
|
/* create the directory */
|
|
kn = kernfs_create_dir(parent->kn, name, mode, cgrp);
|
|
if (IS_ERR(kn)) {
|
|
ret = PTR_ERR(kn);
|
|
goto out_destroy;
|
|
}
|
|
cgrp->kn = kn;
|
|
|
|
/*
|
|
* This extra ref will be put in cgroup_free_fn() and guarantees
|
|
* that @cgrp->kn is always accessible.
|
|
*/
|
|
kernfs_get(kn);
|
|
ret = cgroup_kn_set_ugid(kn);
|
|
if (ret)
|
|
goto out_destroy;
|
|
|
|
ret = css_populate_dir(&cgrp->self);
|
|
if (ret)
|
|
goto out_destroy;
|
|
|
|
ret = cgroup_apply_control_enable(cgrp);
|
|
if (ret)
|
|
goto out_destroy;
|
|
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
ret = sli_cgroup_alloc(cgrp);
|
|
if (ret)
|
|
goto out_destroy;
|
|
#endif
|
|
|
|
if(sysctl_qos_mbuf_enable && cgroup_need_mbuf(cgrp))
|
|
cgrp->mbuf = mbuf_slot_alloc(cgrp);
|
|
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
if (cgroup_need_sli(cgrp))
|
|
cgrp->sctx = sctx_alloc();
|
|
#endif
|
|
|
|
TRACE_CGROUP_PATH(mkdir, cgrp);
|
|
|
|
/* let's create and online css's */
|
|
kernfs_activate(kn);
|
|
|
|
ret = 0;
|
|
goto out_unlock;
|
|
|
|
out_destroy:
|
|
cgroup_destroy_locked(cgrp);
|
|
out_unlock:
|
|
cgroup_kn_unlock(parent_kn);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* This is called when the refcnt of a css is confirmed to be killed.
|
|
* css_tryget_online() is now guaranteed to fail. Tell the subsystem to
|
|
* initate destruction and put the css ref from kill_css().
|
|
*/
|
|
static void css_killed_work_fn(struct work_struct *work)
|
|
{
|
|
struct cgroup_subsys_state *css =
|
|
container_of(work, struct cgroup_subsys_state, destroy_work);
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
do {
|
|
offline_css(css);
|
|
css_put(css);
|
|
/* @css can't go away while we're holding cgroup_mutex */
|
|
css = css->parent;
|
|
} while (css && atomic_dec_and_test(&css->online_cnt));
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
}
|
|
|
|
/* css kill confirmation processing requires process context, bounce */
|
|
static void css_killed_ref_fn(struct percpu_ref *ref)
|
|
{
|
|
struct cgroup_subsys_state *css =
|
|
container_of(ref, struct cgroup_subsys_state, refcnt);
|
|
|
|
if (atomic_dec_and_test(&css->online_cnt)) {
|
|
INIT_WORK(&css->destroy_work, css_killed_work_fn);
|
|
queue_work(cgroup_destroy_wq, &css->destroy_work);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* kill_css - destroy a css
|
|
* @css: css to destroy
|
|
*
|
|
* This function initiates destruction of @css by removing cgroup interface
|
|
* files and putting its base reference. ->css_offline() will be invoked
|
|
* asynchronously once css_tryget_online() is guaranteed to fail and when
|
|
* the reference count reaches zero, @css will be released.
|
|
*/
|
|
static void kill_css(struct cgroup_subsys_state *css)
|
|
{
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
if (css->flags & CSS_DYING)
|
|
return;
|
|
|
|
css->flags |= CSS_DYING;
|
|
|
|
/*
|
|
* This must happen before css is disassociated with its cgroup.
|
|
* See seq_css() for details.
|
|
*/
|
|
css_clear_dir(css);
|
|
|
|
/*
|
|
* Killing would put the base ref, but we need to keep it alive
|
|
* until after ->css_offline().
|
|
*/
|
|
css_get(css);
|
|
|
|
/*
|
|
* cgroup core guarantees that, by the time ->css_offline() is
|
|
* invoked, no new css reference will be given out via
|
|
* css_tryget_online(). We can't simply call percpu_ref_kill() and
|
|
* proceed to offlining css's because percpu_ref_kill() doesn't
|
|
* guarantee that the ref is seen as killed on all CPUs on return.
|
|
*
|
|
* Use percpu_ref_kill_and_confirm() to get notifications as each
|
|
* css is confirmed to be seen as killed on all CPUs.
|
|
*/
|
|
percpu_ref_kill_and_confirm(&css->refcnt, css_killed_ref_fn);
|
|
}
|
|
|
|
/**
|
|
* cgroup_destroy_locked - the first stage of cgroup destruction
|
|
* @cgrp: cgroup to be destroyed
|
|
*
|
|
* css's make use of percpu refcnts whose killing latency shouldn't be
|
|
* exposed to userland and are RCU protected. Also, cgroup core needs to
|
|
* guarantee that css_tryget_online() won't succeed by the time
|
|
* ->css_offline() is invoked. To satisfy all the requirements,
|
|
* destruction is implemented in the following two steps.
|
|
*
|
|
* s1. Verify @cgrp can be destroyed and mark it dying. Remove all
|
|
* userland visible parts and start killing the percpu refcnts of
|
|
* css's. Set up so that the next stage will be kicked off once all
|
|
* the percpu refcnts are confirmed to be killed.
|
|
*
|
|
* s2. Invoke ->css_offline(), mark the cgroup dead and proceed with the
|
|
* rest of destruction. Once all cgroup references are gone, the
|
|
* cgroup is RCU-freed.
|
|
*
|
|
* This function implements s1. After this step, @cgrp is gone as far as
|
|
* the userland is concerned and a new cgroup with the same name may be
|
|
* created. As cgroup doesn't care about the names internally, this
|
|
* doesn't cause any problem.
|
|
*/
|
|
static int cgroup_destroy_locked(struct cgroup *cgrp)
|
|
__releases(&cgroup_mutex) __acquires(&cgroup_mutex)
|
|
{
|
|
struct cgroup *tcgrp, *parent = cgroup_parent(cgrp);
|
|
struct cgroup_subsys_state *css;
|
|
struct cgrp_cset_link *link;
|
|
int ssid;
|
|
|
|
lockdep_assert_held(&cgroup_mutex);
|
|
|
|
/*
|
|
* Only migration can raise populated from zero and we're already
|
|
* holding cgroup_mutex.
|
|
*/
|
|
if (cgroup_is_populated(cgrp))
|
|
return -EBUSY;
|
|
|
|
/*
|
|
* Make sure there's no live children. We can't test emptiness of
|
|
* ->self.children as dead children linger on it while being
|
|
* drained; otherwise, "rmdir parent/child parent" may fail.
|
|
*/
|
|
if (css_has_online_children(&cgrp->self))
|
|
return -EBUSY;
|
|
|
|
/*
|
|
* Mark @cgrp and the associated csets dead. The former prevents
|
|
* further task migration and child creation by disabling
|
|
* cgroup_lock_live_group(). The latter makes the csets ignored by
|
|
* the migration path.
|
|
*/
|
|
cgrp->self.flags &= ~CSS_ONLINE;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
list_for_each_entry(link, &cgrp->cset_links, cset_link)
|
|
link->cset->dead = true;
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
/* initiate massacre of all css's */
|
|
for_each_css(css, ssid, cgrp)
|
|
kill_css(css);
|
|
|
|
/* clear and remove @cgrp dir, @cgrp has an extra ref on its kn */
|
|
css_clear_dir(&cgrp->self);
|
|
kernfs_remove(cgrp->kn);
|
|
|
|
if (parent && cgroup_is_threaded(cgrp))
|
|
parent->nr_threaded_children--;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
for (tcgrp = cgroup_parent(cgrp); tcgrp; tcgrp = cgroup_parent(tcgrp)) {
|
|
tcgrp->nr_descendants--;
|
|
tcgrp->nr_dying_descendants++;
|
|
/*
|
|
* If the dying cgroup is frozen, decrease frozen descendants
|
|
* counters of ancestor cgroups.
|
|
*/
|
|
if (test_bit(CGRP_FROZEN, &cgrp->flags))
|
|
tcgrp->freezer.nr_frozen_descendants--;
|
|
}
|
|
spin_unlock_irq(&css_set_lock);
|
|
|
|
cgroup1_check_for_release(parent);
|
|
|
|
cgroup_bpf_offline(cgrp);
|
|
|
|
if (cgrp->mbuf)
|
|
mbuf_free(cgrp);
|
|
|
|
#ifdef CONFIG_CGROUP_SLI
|
|
if (cgrp->sctx)
|
|
sctx_free(cgrp);
|
|
#endif
|
|
/* put the base reference */
|
|
percpu_ref_kill(&cgrp->self.refcnt);
|
|
|
|
return 0;
|
|
};
|
|
|
|
int cgroup_rmdir(struct kernfs_node *kn)
|
|
{
|
|
struct cgroup *cgrp;
|
|
int ret = 0;
|
|
|
|
cgrp = cgroup_kn_lock_live(kn, false);
|
|
if (!cgrp)
|
|
return 0;
|
|
|
|
ret = cgroup_destroy_locked(cgrp);
|
|
if (!ret)
|
|
TRACE_CGROUP_PATH(rmdir, cgrp);
|
|
|
|
cgroup_kn_unlock(kn);
|
|
return ret;
|
|
}
|
|
|
|
static struct kernfs_syscall_ops cgroup_kf_syscall_ops = {
|
|
.show_options = cgroup_show_options,
|
|
.mkdir = cgroup_mkdir,
|
|
.rmdir = cgroup_rmdir,
|
|
.show_path = cgroup_show_path,
|
|
};
|
|
|
|
static void __init cgroup_init_subsys(struct cgroup_subsys *ss, bool early)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
|
|
pr_debug("Initializing cgroup subsys %s\n", ss->name);
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
idr_init(&ss->css_idr);
|
|
INIT_LIST_HEAD(&ss->cfts);
|
|
|
|
/* Create the root cgroup state for this subsystem */
|
|
ss->root = &cgrp_dfl_root;
|
|
css = ss->css_alloc(cgroup_css(&cgrp_dfl_root.cgrp, ss));
|
|
/* We don't handle early failures gracefully */
|
|
BUG_ON(IS_ERR(css));
|
|
init_and_link_css(css, ss, &cgrp_dfl_root.cgrp);
|
|
|
|
/*
|
|
* Root csses are never destroyed and we can't initialize
|
|
* percpu_ref during early init. Disable refcnting.
|
|
*/
|
|
css->flags |= CSS_NO_REF;
|
|
|
|
if (early) {
|
|
/* allocation can't be done safely during early init */
|
|
css->id = 1;
|
|
} else {
|
|
css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2, GFP_KERNEL);
|
|
BUG_ON(css->id < 0);
|
|
}
|
|
|
|
/* Update the init_css_set to contain a subsys
|
|
* pointer to this state - since the subsystem is
|
|
* newly registered, all tasks and hence the
|
|
* init_css_set is in the subsystem's root cgroup. */
|
|
init_css_set.subsys[ss->id] = css;
|
|
|
|
have_fork_callback |= (bool)ss->fork << ss->id;
|
|
have_exit_callback |= (bool)ss->exit << ss->id;
|
|
have_release_callback |= (bool)ss->release << ss->id;
|
|
have_canfork_callback |= (bool)ss->can_fork << ss->id;
|
|
|
|
/* At system boot, before all subsystems have been
|
|
* registered, no tasks have been forked, so we don't
|
|
* need to invoke fork callbacks here. */
|
|
BUG_ON(!list_empty(&init_task.tasks));
|
|
|
|
BUG_ON(online_css(css));
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
}
|
|
|
|
/**
|
|
* cgroup_init_early - cgroup initialization at system boot
|
|
*
|
|
* Initialize cgroups at system boot, and initialize any
|
|
* subsystems that request early init.
|
|
*/
|
|
int __init cgroup_init_early(void)
|
|
{
|
|
static struct cgroup_fs_context __initdata ctx;
|
|
struct cgroup_subsys *ss;
|
|
int i;
|
|
|
|
ctx.root = &cgrp_dfl_root;
|
|
init_cgroup_root(&ctx);
|
|
cgrp_dfl_root.cgrp.self.flags |= CSS_NO_REF;
|
|
|
|
RCU_INIT_POINTER(init_task.cgroups, &init_css_set);
|
|
|
|
for_each_subsys(ss, i) {
|
|
WARN(!ss->css_alloc || !ss->css_free || ss->name || ss->id,
|
|
"invalid cgroup_subsys %d:%s css_alloc=%p css_free=%p id:name=%d:%s\n",
|
|
i, cgroup_subsys_name[i], ss->css_alloc, ss->css_free,
|
|
ss->id, ss->name);
|
|
WARN(strlen(cgroup_subsys_name[i]) > MAX_CGROUP_TYPE_NAMELEN,
|
|
"cgroup_subsys_name %s too long\n", cgroup_subsys_name[i]);
|
|
|
|
ss->id = i;
|
|
ss->name = cgroup_subsys_name[i];
|
|
if (!ss->legacy_name)
|
|
ss->legacy_name = cgroup_subsys_name[i];
|
|
|
|
if (ss->early_init)
|
|
cgroup_init_subsys(ss, true);
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* cgroup_init - cgroup initialization
|
|
*
|
|
* Register cgroup filesystem and /proc file, and initialize
|
|
* any subsystems that didn't request early init.
|
|
*/
|
|
int __init cgroup_init(void)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
BUILD_BUG_ON(CGROUP_SUBSYS_COUNT > 16);
|
|
BUG_ON(cgroup_init_cftypes(NULL, cgroup_base_files));
|
|
BUG_ON(cgroup_init_cftypes(NULL, cgroup1_base_files));
|
|
|
|
cgroup_rstat_boot();
|
|
|
|
/*
|
|
* The latency of the synchronize_rcu() is too high for cgroups,
|
|
* avoid it at the cost of forcing all readers into the slow path.
|
|
*/
|
|
rcu_sync_enter_start(&cgroup_threadgroup_rwsem.rss);
|
|
|
|
get_user_ns(init_cgroup_ns.user_ns);
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
/*
|
|
* Add init_css_set to the hash table so that dfl_root can link to
|
|
* it during init.
|
|
*/
|
|
hash_add(css_set_table, &init_css_set.hlist,
|
|
css_set_hash(init_css_set.subsys));
|
|
|
|
BUG_ON(cgroup_setup_root(&cgrp_dfl_root, 0));
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
|
|
for_each_subsys(ss, ssid) {
|
|
if (ss->early_init) {
|
|
struct cgroup_subsys_state *css =
|
|
init_css_set.subsys[ss->id];
|
|
|
|
css->id = cgroup_idr_alloc(&ss->css_idr, css, 1, 2,
|
|
GFP_KERNEL);
|
|
BUG_ON(css->id < 0);
|
|
} else {
|
|
cgroup_init_subsys(ss, false);
|
|
}
|
|
|
|
list_add_tail(&init_css_set.e_cset_node[ssid],
|
|
&cgrp_dfl_root.cgrp.e_csets[ssid]);
|
|
|
|
/*
|
|
* Setting dfl_root subsys_mask needs to consider the
|
|
* disabled flag and cftype registration needs kmalloc,
|
|
* both of which aren't available during early_init.
|
|
*/
|
|
if (!cgroup_ssid_enabled(ssid))
|
|
continue;
|
|
|
|
if (cgroup1_ssid_disabled(ssid))
|
|
printk(KERN_INFO "Disabling %s control group subsystem in v1 mounts\n",
|
|
ss->name);
|
|
|
|
cgrp_dfl_root.subsys_mask |= 1 << ss->id;
|
|
|
|
/* implicit controllers must be threaded too */
|
|
WARN_ON(ss->implicit_on_dfl && !ss->threaded);
|
|
|
|
if (ss->implicit_on_dfl)
|
|
cgrp_dfl_implicit_ss_mask |= 1 << ss->id;
|
|
else if (!ss->dfl_cftypes)
|
|
cgrp_dfl_inhibit_ss_mask |= 1 << ss->id;
|
|
|
|
if (ss->threaded)
|
|
cgrp_dfl_threaded_ss_mask |= 1 << ss->id;
|
|
|
|
if (ss->dfl_cftypes == ss->legacy_cftypes) {
|
|
WARN_ON(cgroup_add_cftypes(ss, ss->dfl_cftypes));
|
|
} else {
|
|
WARN_ON(cgroup_add_dfl_cftypes(ss, ss->dfl_cftypes));
|
|
WARN_ON(cgroup_add_legacy_cftypes(ss, ss->legacy_cftypes));
|
|
}
|
|
|
|
if (ss->bind)
|
|
ss->bind(init_css_set.subsys[ssid]);
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
css_populate_dir(init_css_set.subsys[ssid]);
|
|
mutex_unlock(&cgroup_mutex);
|
|
}
|
|
|
|
/* init_css_set.subsys[] has been updated, re-hash */
|
|
hash_del(&init_css_set.hlist);
|
|
hash_add(css_set_table, &init_css_set.hlist,
|
|
css_set_hash(init_css_set.subsys));
|
|
|
|
WARN_ON(sysfs_create_mount_point(fs_kobj, "cgroup"));
|
|
WARN_ON(register_filesystem(&cgroup_fs_type));
|
|
WARN_ON(register_filesystem(&cgroup2_fs_type));
|
|
WARN_ON(!proc_create_single("cgroups", 0, NULL, proc_cgroupstats_show));
|
|
#ifdef CONFIG_CPUSETS
|
|
WARN_ON(register_filesystem(&cpuset_fs_type));
|
|
#endif
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init cgroup_wq_init(void)
|
|
{
|
|
/*
|
|
* There isn't much point in executing destruction path in
|
|
* parallel. Good chunk is serialized with cgroup_mutex anyway.
|
|
* Use 1 for @max_active.
|
|
*
|
|
* We would prefer to do this in cgroup_init() above, but that
|
|
* is called before init_workqueues(): so leave this until after.
|
|
*/
|
|
cgroup_destroy_wq = alloc_workqueue("cgroup_destroy", 0, 1);
|
|
BUG_ON(!cgroup_destroy_wq);
|
|
return 0;
|
|
}
|
|
core_initcall(cgroup_wq_init);
|
|
|
|
void cgroup_path_from_kernfs_id(const union kernfs_node_id *id,
|
|
char *buf, size_t buflen)
|
|
{
|
|
struct kernfs_node *kn;
|
|
|
|
kn = kernfs_get_node_by_id(cgrp_dfl_root.kf_root, id);
|
|
if (!kn)
|
|
return;
|
|
kernfs_path(kn, buf, buflen);
|
|
kernfs_put(kn);
|
|
}
|
|
|
|
/*
|
|
* proc_cgroup_show()
|
|
* - Print task's cgroup paths into seq_file, one line for each hierarchy
|
|
* - Used for /proc/<pid>/cgroup.
|
|
*/
|
|
int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
|
|
struct pid *pid, struct task_struct *tsk)
|
|
{
|
|
char *buf;
|
|
int retval;
|
|
struct cgroup_root *root;
|
|
|
|
retval = -ENOMEM;
|
|
buf = kmalloc(PATH_MAX, GFP_KERNEL);
|
|
if (!buf)
|
|
goto out;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
spin_lock_irq(&css_set_lock);
|
|
|
|
for_each_root(root) {
|
|
struct cgroup_subsys *ss;
|
|
struct cgroup *cgrp;
|
|
int ssid, count = 0;
|
|
|
|
if (root == &cgrp_dfl_root && !cgrp_dfl_visible)
|
|
continue;
|
|
|
|
seq_printf(m, "%d:", root->hierarchy_id);
|
|
if (root != &cgrp_dfl_root)
|
|
for_each_subsys(ss, ssid)
|
|
if (root->subsys_mask & (1 << ssid))
|
|
seq_printf(m, "%s%s", count++ ? "," : "",
|
|
ss->legacy_name);
|
|
if (strlen(root->name))
|
|
seq_printf(m, "%sname=%s", count ? "," : "",
|
|
root->name);
|
|
seq_putc(m, ':');
|
|
|
|
cgrp = task_cgroup_from_root(tsk, root);
|
|
|
|
/*
|
|
* On traditional hierarchies, all zombie tasks show up as
|
|
* belonging to the root cgroup. On the default hierarchy,
|
|
* while a zombie doesn't show up in "cgroup.procs" and
|
|
* thus can't be migrated, its /proc/PID/cgroup keeps
|
|
* reporting the cgroup it belonged to before exiting. If
|
|
* the cgroup is removed before the zombie is reaped,
|
|
* " (deleted)" is appended to the cgroup path.
|
|
*/
|
|
if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
|
|
retval = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
|
|
current->nsproxy->cgroup_ns);
|
|
if (retval >= PATH_MAX)
|
|
retval = -ENAMETOOLONG;
|
|
if (retval < 0)
|
|
goto out_unlock;
|
|
|
|
seq_puts(m, buf);
|
|
} else {
|
|
seq_puts(m, "/");
|
|
}
|
|
|
|
if (cgroup_on_dfl(cgrp) && cgroup_is_dead(cgrp))
|
|
seq_puts(m, " (deleted)\n");
|
|
else
|
|
seq_putc(m, '\n');
|
|
}
|
|
|
|
retval = 0;
|
|
out_unlock:
|
|
spin_unlock_irq(&css_set_lock);
|
|
mutex_unlock(&cgroup_mutex);
|
|
kfree(buf);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* cgroup_fork - initialize cgroup related fields during copy_process()
|
|
* @child: pointer to task_struct of forking parent process.
|
|
*
|
|
* A task is associated with the init_css_set until cgroup_post_fork()
|
|
* attaches it to the parent's css_set. Empty cg_list indicates that
|
|
* @child isn't holding reference to its css_set.
|
|
*/
|
|
void cgroup_fork(struct task_struct *child)
|
|
{
|
|
RCU_INIT_POINTER(child->cgroups, &init_css_set);
|
|
INIT_LIST_HEAD(&child->cg_list);
|
|
}
|
|
|
|
/**
|
|
* cgroup_can_fork - called on a new task before the process is exposed
|
|
* @child: the task in question.
|
|
*
|
|
* This calls the subsystem can_fork() callbacks. If the can_fork() callback
|
|
* returns an error, the fork aborts with that error code. This allows for
|
|
* a cgroup subsystem to conditionally allow or deny new forks.
|
|
*/
|
|
int cgroup_can_fork(struct task_struct *child)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int i, j, ret;
|
|
|
|
do_each_subsys_mask(ss, i, have_canfork_callback) {
|
|
ret = ss->can_fork(child);
|
|
if (ret)
|
|
goto out_revert;
|
|
} while_each_subsys_mask();
|
|
|
|
return 0;
|
|
|
|
out_revert:
|
|
for_each_subsys(ss, j) {
|
|
if (j >= i)
|
|
break;
|
|
if (ss->cancel_fork)
|
|
ss->cancel_fork(child);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* cgroup_cancel_fork - called if a fork failed after cgroup_can_fork()
|
|
* @child: the task in question
|
|
*
|
|
* This calls the cancel_fork() callbacks if a fork failed *after*
|
|
* cgroup_can_fork() succeded.
|
|
*/
|
|
void cgroup_cancel_fork(struct task_struct *child)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int i;
|
|
|
|
for_each_subsys(ss, i)
|
|
if (ss->cancel_fork)
|
|
ss->cancel_fork(child);
|
|
}
|
|
|
|
/**
|
|
* cgroup_post_fork - called on a new task after adding it to the task list
|
|
* @child: the task in question
|
|
*
|
|
* Adds the task to the list running through its css_set if necessary and
|
|
* call the subsystem fork() callbacks. Has to be after the task is
|
|
* visible on the task list in case we race with the first call to
|
|
* cgroup_task_iter_start() - to guarantee that the new task ends up on its
|
|
* list.
|
|
*/
|
|
void cgroup_post_fork(struct task_struct *child)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int i;
|
|
|
|
/*
|
|
* This may race against cgroup_enable_task_cg_lists(). As that
|
|
* function sets use_task_css_set_links before grabbing
|
|
* tasklist_lock and we just went through tasklist_lock to add
|
|
* @child, it's guaranteed that either we see the set
|
|
* use_task_css_set_links or cgroup_enable_task_cg_lists() sees
|
|
* @child during its iteration.
|
|
*
|
|
* If we won the race, @child is associated with %current's
|
|
* css_set. Grabbing css_set_lock guarantees both that the
|
|
* association is stable, and, on completion of the parent's
|
|
* migration, @child is visible in the source of migration or
|
|
* already in the destination cgroup. This guarantee is necessary
|
|
* when implementing operations which need to migrate all tasks of
|
|
* a cgroup to another.
|
|
*
|
|
* Note that if we lose to cgroup_enable_task_cg_lists(), @child
|
|
* will remain in init_css_set. This is safe because all tasks are
|
|
* in the init_css_set before cg_links is enabled and there's no
|
|
* operation which transfers all tasks out of init_css_set.
|
|
*/
|
|
if (use_task_css_set_links) {
|
|
struct css_set *cset;
|
|
|
|
spin_lock_irq(&css_set_lock);
|
|
cset = task_css_set(current);
|
|
if (list_empty(&child->cg_list)) {
|
|
get_css_set(cset);
|
|
cset->nr_tasks++;
|
|
do_css_account_procs(child, cset, 1);
|
|
css_set_move_task(child, NULL, cset, false);
|
|
}
|
|
|
|
/*
|
|
* If the cgroup has to be frozen, the new task has too.
|
|
* Let's set the JOBCTL_TRAP_FREEZE jobctl bit to get
|
|
* the task into the frozen state.
|
|
*/
|
|
if (unlikely(cgroup_task_freeze(child))) {
|
|
spin_lock(&child->sighand->siglock);
|
|
WARN_ON_ONCE(child->frozen);
|
|
child->jobctl |= JOBCTL_TRAP_FREEZE;
|
|
spin_unlock(&child->sighand->siglock);
|
|
|
|
/*
|
|
* Calling cgroup_update_frozen() isn't required here,
|
|
* because it will be called anyway a bit later
|
|
* from do_freezer_trap(). So we avoid cgroup's
|
|
* transient switch from the frozen state and back.
|
|
*/
|
|
}
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
}
|
|
|
|
/*
|
|
* Call ss->fork(). This must happen after @child is linked on
|
|
* css_set; otherwise, @child might change state between ->fork()
|
|
* and addition to css_set.
|
|
*/
|
|
do_each_subsys_mask(ss, i, have_fork_callback) {
|
|
ss->fork(child);
|
|
} while_each_subsys_mask();
|
|
}
|
|
|
|
/**
|
|
* cgroup_exit - detach cgroup from exiting task
|
|
* @tsk: pointer to task_struct of exiting process
|
|
*
|
|
* Description: Detach cgroup from @tsk and release it.
|
|
*
|
|
* Note that cgroups marked notify_on_release force every task in
|
|
* them to take the global cgroup_mutex mutex when exiting.
|
|
* This could impact scaling on very large systems. Be reluctant to
|
|
* use notify_on_release cgroups where very high task exit scaling
|
|
* is required on large systems.
|
|
*
|
|
* We set the exiting tasks cgroup to the root cgroup (top_cgroup). We
|
|
* call cgroup_exit() while the task is still competent to handle
|
|
* notify_on_release(), then leave the task attached to the root cgroup in
|
|
* each hierarchy for the remainder of its exit. No need to bother with
|
|
* init_css_set refcnting. init_css_set never goes away and we can't race
|
|
* with migration path - PF_EXITING is visible to migration path.
|
|
*/
|
|
void cgroup_exit(struct task_struct *tsk)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
struct css_set *cset;
|
|
int i;
|
|
|
|
/*
|
|
* Unlink from @tsk from its css_set. As migration path can't race
|
|
* with us, we can check css_set and cg_list without synchronization.
|
|
*/
|
|
cset = task_css_set(tsk);
|
|
|
|
if (!list_empty(&tsk->cg_list)) {
|
|
spin_lock_irq(&css_set_lock);
|
|
css_set_move_task(tsk, cset, NULL, false);
|
|
list_add_tail(&tsk->cg_list, &cset->dying_tasks);
|
|
cset->nr_tasks--;
|
|
do_css_account_procs(tsk, cset, -1);
|
|
|
|
WARN_ON_ONCE(cgroup_task_frozen(tsk));
|
|
if (unlikely(cgroup_task_freeze(tsk)))
|
|
cgroup_update_frozen(task_dfl_cgroup(tsk));
|
|
|
|
spin_unlock_irq(&css_set_lock);
|
|
} else {
|
|
get_css_set(cset);
|
|
}
|
|
|
|
/* see cgroup_post_fork() for details */
|
|
do_each_subsys_mask(ss, i, have_exit_callback) {
|
|
ss->exit(tsk);
|
|
} while_each_subsys_mask();
|
|
}
|
|
|
|
void cgroup_release(struct task_struct *task)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
|
|
do_each_subsys_mask(ss, ssid, have_release_callback) {
|
|
ss->release(task);
|
|
} while_each_subsys_mask();
|
|
|
|
if (use_task_css_set_links) {
|
|
spin_lock_irq(&css_set_lock);
|
|
css_set_skip_task_iters(task_css_set(task), task);
|
|
list_del_init(&task->cg_list);
|
|
spin_unlock_irq(&css_set_lock);
|
|
}
|
|
}
|
|
|
|
void cgroup_free(struct task_struct *task)
|
|
{
|
|
struct css_set *cset = task_css_set(task);
|
|
put_css_set(cset);
|
|
}
|
|
|
|
static int __init cgroup_disable(char *str)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
char *token;
|
|
int i;
|
|
|
|
while ((token = strsep(&str, ",")) != NULL) {
|
|
if (!*token)
|
|
continue;
|
|
|
|
for_each_subsys(ss, i) {
|
|
if (strcmp(token, ss->name) &&
|
|
strcmp(token, ss->legacy_name))
|
|
continue;
|
|
|
|
static_branch_disable(cgroup_subsys_enabled_key[i]);
|
|
pr_info("Disabling %s control group subsystem\n",
|
|
ss->name);
|
|
|
|
#ifdef CONFIG_CGROUP_WRITEBACK
|
|
if ((i == memory_cgrp_id) || (i == io_cgrp_id)) {
|
|
pr_info("Disable cgv1 buffer IO writeback\n");
|
|
sysctl_io_cgv1_buff_wb_enabled = 0;
|
|
}
|
|
#endif
|
|
}
|
|
}
|
|
return 1;
|
|
}
|
|
__setup("cgroup_disable=", cgroup_disable);
|
|
|
|
void __init __weak enable_debug_cgroup(void) { }
|
|
|
|
static int __init enable_cgroup_debug(char *str)
|
|
{
|
|
cgroup_debug = true;
|
|
enable_debug_cgroup();
|
|
return 1;
|
|
}
|
|
__setup("cgroup_debug", enable_cgroup_debug);
|
|
|
|
/**
|
|
* css_tryget_online_from_dir - get corresponding css from a cgroup dentry
|
|
* @dentry: directory dentry of interest
|
|
* @ss: subsystem of interest
|
|
*
|
|
* If @dentry is a directory for a cgroup which has @ss enabled on it, try
|
|
* to get the corresponding css and return it. If such css doesn't exist
|
|
* or can't be pinned, an ERR_PTR value is returned.
|
|
*/
|
|
struct cgroup_subsys_state *css_tryget_online_from_dir(struct dentry *dentry,
|
|
struct cgroup_subsys *ss)
|
|
{
|
|
struct kernfs_node *kn = kernfs_node_from_dentry(dentry);
|
|
struct file_system_type *s_type = dentry->d_sb->s_type;
|
|
struct cgroup_subsys_state *css = NULL;
|
|
struct cgroup *cgrp;
|
|
|
|
/* is @dentry a cgroup dir? */
|
|
if ((s_type != &cgroup_fs_type && s_type != &cgroup2_fs_type) ||
|
|
!kn || kernfs_type(kn) != KERNFS_DIR)
|
|
return ERR_PTR(-EBADF);
|
|
|
|
rcu_read_lock();
|
|
|
|
/*
|
|
* This path doesn't originate from kernfs and @kn could already
|
|
* have been or be removed at any point. @kn->priv is RCU
|
|
* protected for this access. See css_release_work_fn() for details.
|
|
*/
|
|
cgrp = rcu_dereference(*(void __rcu __force **)&kn->priv);
|
|
if (cgrp)
|
|
css = cgroup_css(cgrp, ss);
|
|
|
|
if (!css || !css_tryget_online(css))
|
|
css = ERR_PTR(-ENOENT);
|
|
|
|
rcu_read_unlock();
|
|
return css;
|
|
}
|
|
|
|
/**
|
|
* css_from_id - lookup css by id
|
|
* @id: the cgroup id
|
|
* @ss: cgroup subsys to be looked into
|
|
*
|
|
* Returns the css if there's valid one with @id, otherwise returns NULL.
|
|
* Should be called under rcu_read_lock().
|
|
*/
|
|
struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
|
|
{
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
return idr_find(&ss->css_idr, id);
|
|
}
|
|
|
|
/**
|
|
* cgroup_get_from_path - lookup and get a cgroup from its default hierarchy path
|
|
* @path: path on the default hierarchy
|
|
*
|
|
* Find the cgroup at @path on the default hierarchy, increment its
|
|
* reference count and return it. Returns pointer to the found cgroup on
|
|
* success, ERR_PTR(-ENOENT) if @path doens't exist and ERR_PTR(-ENOTDIR)
|
|
* if @path points to a non-directory.
|
|
*/
|
|
struct cgroup *cgroup_get_from_path(const char *path)
|
|
{
|
|
struct kernfs_node *kn;
|
|
struct cgroup *cgrp;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
|
|
kn = kernfs_walk_and_get(cgrp_dfl_root.cgrp.kn, path);
|
|
if (kn) {
|
|
if (kernfs_type(kn) == KERNFS_DIR) {
|
|
cgrp = kn->priv;
|
|
cgroup_get_live(cgrp);
|
|
} else {
|
|
cgrp = ERR_PTR(-ENOTDIR);
|
|
}
|
|
kernfs_put(kn);
|
|
} else {
|
|
cgrp = ERR_PTR(-ENOENT);
|
|
}
|
|
|
|
mutex_unlock(&cgroup_mutex);
|
|
return cgrp;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cgroup_get_from_path);
|
|
|
|
/**
|
|
* cgroup_get_from_fd - get a cgroup pointer from a fd
|
|
* @fd: fd obtained by open(cgroup2_dir)
|
|
*
|
|
* Find the cgroup from a fd which should be obtained
|
|
* by opening a cgroup directory. Returns a pointer to the
|
|
* cgroup on success. ERR_PTR is returned if the cgroup
|
|
* cannot be found.
|
|
*/
|
|
struct cgroup *cgroup_get_from_fd(int fd)
|
|
{
|
|
struct cgroup_subsys_state *css;
|
|
struct cgroup *cgrp;
|
|
struct file *f;
|
|
|
|
f = fget_raw(fd);
|
|
if (!f)
|
|
return ERR_PTR(-EBADF);
|
|
|
|
css = css_tryget_online_from_dir(f->f_path.dentry, NULL);
|
|
fput(f);
|
|
if (IS_ERR(css))
|
|
return ERR_CAST(css);
|
|
|
|
cgrp = css->cgroup;
|
|
if (!cgroup_on_dfl(cgrp)) {
|
|
cgroup_put(cgrp);
|
|
|
|
#ifdef CONFIG_CGROUP_V1_BPF
|
|
cgrp = &cgrp_dfl_root.cgrp;
|
|
cgroup_get(cgrp);
|
|
#else
|
|
return ERR_PTR(-EBADF);
|
|
#endif
|
|
}
|
|
|
|
return cgrp;
|
|
}
|
|
EXPORT_SYMBOL_GPL(cgroup_get_from_fd);
|
|
|
|
static u64 power_of_ten(int power)
|
|
{
|
|
u64 v = 1;
|
|
while (power--)
|
|
v *= 10;
|
|
return v;
|
|
}
|
|
|
|
/**
|
|
* cgroup_parse_float - parse a floating number
|
|
* @input: input string
|
|
* @dec_shift: number of decimal digits to shift
|
|
* @v: output
|
|
*
|
|
* Parse a decimal floating point number in @input and store the result in
|
|
* @v with decimal point right shifted @dec_shift times. For example, if
|
|
* @input is "12.3456" and @dec_shift is 3, *@v will be set to 12345.
|
|
* Returns 0 on success, -errno otherwise.
|
|
*
|
|
* There's nothing cgroup specific about this function except that it's
|
|
* currently the only user.
|
|
*/
|
|
int cgroup_parse_float(const char *input, unsigned dec_shift, s64 *v)
|
|
{
|
|
s64 whole, frac = 0;
|
|
int fstart = 0, fend = 0, flen;
|
|
|
|
if (!sscanf(input, "%lld.%n%lld%n", &whole, &fstart, &frac, &fend))
|
|
return -EINVAL;
|
|
if (frac < 0)
|
|
return -EINVAL;
|
|
|
|
flen = fend > fstart ? fend - fstart : 0;
|
|
if (flen < dec_shift)
|
|
frac *= power_of_ten(dec_shift - flen);
|
|
else
|
|
frac = DIV_ROUND_CLOSEST_ULL(frac, power_of_ten(flen - dec_shift));
|
|
|
|
*v = whole * power_of_ten(dec_shift) + frac;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* sock->sk_cgrp_data handling. For more info, see sock_cgroup_data
|
|
* definition in cgroup-defs.h.
|
|
*/
|
|
#ifdef CONFIG_SOCK_CGROUP_DATA
|
|
|
|
#if defined(CONFIG_CGROUP_NET_PRIO) || defined(CONFIG_CGROUP_NET_CLASSID)
|
|
|
|
DEFINE_SPINLOCK(cgroup_sk_update_lock);
|
|
static bool cgroup_sk_alloc_disabled __read_mostly;
|
|
|
|
void cgroup_sk_alloc_disable(void)
|
|
{
|
|
if (cgroup_sk_alloc_disabled)
|
|
return;
|
|
pr_info("cgroup: disabling cgroup2 socket matching due to net_prio or net_cls activation\n");
|
|
cgroup_sk_alloc_disabled = true;
|
|
}
|
|
|
|
#else
|
|
|
|
#define cgroup_sk_alloc_disabled false
|
|
|
|
#endif
|
|
|
|
void cgroup_sk_alloc(struct sock_cgroup_data *skcd)
|
|
{
|
|
if (cgroup_sk_alloc_disabled) {
|
|
skcd->no_refcnt = 1;
|
|
return;
|
|
}
|
|
|
|
/* Don't associate the sock with unrelated interrupted task's cgroup. */
|
|
if (in_interrupt())
|
|
return;
|
|
|
|
rcu_read_lock();
|
|
|
|
while (true) {
|
|
struct css_set *cset;
|
|
|
|
cset = task_css_set(current);
|
|
if (likely(cgroup_tryget(cset->dfl_cgrp))) {
|
|
skcd->val = (unsigned long)cset->dfl_cgrp;
|
|
cgroup_bpf_get(cset->dfl_cgrp);
|
|
break;
|
|
}
|
|
cpu_relax();
|
|
}
|
|
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
void cgroup_sk_clone(struct sock_cgroup_data *skcd)
|
|
{
|
|
if (skcd->val) {
|
|
if (skcd->no_refcnt)
|
|
return;
|
|
/*
|
|
* We might be cloning a socket which is left in an empty
|
|
* cgroup and the cgroup might have already been rmdir'd.
|
|
* Don't use cgroup_get_live().
|
|
*/
|
|
cgroup_get(sock_cgroup_ptr(skcd));
|
|
cgroup_bpf_get(sock_cgroup_ptr(skcd));
|
|
}
|
|
}
|
|
|
|
void cgroup_sk_free(struct sock_cgroup_data *skcd)
|
|
{
|
|
struct cgroup *cgrp = sock_cgroup_ptr(skcd);
|
|
|
|
if (skcd->no_refcnt)
|
|
return;
|
|
cgroup_bpf_put(cgrp);
|
|
cgroup_put(cgrp);
|
|
}
|
|
|
|
#endif /* CONFIG_SOCK_CGROUP_DATA */
|
|
|
|
#ifdef CONFIG_CGROUP_BPF
|
|
int cgroup_bpf_attach(struct cgroup *cgrp,
|
|
struct bpf_prog *prog, struct bpf_prog *replace_prog,
|
|
struct bpf_cgroup_link *link,
|
|
enum bpf_attach_type type,
|
|
u32 flags)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
ret = __cgroup_bpf_attach(cgrp, prog, replace_prog, link, type, flags);
|
|
mutex_unlock(&cgroup_mutex);
|
|
return ret;
|
|
}
|
|
|
|
int cgroup_bpf_detach(struct cgroup *cgrp, struct bpf_prog *prog,
|
|
enum bpf_attach_type type)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
ret = __cgroup_bpf_detach(cgrp, prog, NULL, type);
|
|
mutex_unlock(&cgroup_mutex);
|
|
return ret;
|
|
}
|
|
|
|
int cgroup_bpf_query(struct cgroup *cgrp, const union bpf_attr *attr,
|
|
union bpf_attr __user *uattr)
|
|
{
|
|
int ret;
|
|
|
|
mutex_lock(&cgroup_mutex);
|
|
ret = __cgroup_bpf_query(cgrp, attr, uattr);
|
|
mutex_unlock(&cgroup_mutex);
|
|
return ret;
|
|
}
|
|
#endif /* CONFIG_CGROUP_BPF */
|
|
|
|
#ifdef CONFIG_SYSFS
|
|
static ssize_t show_delegatable_files(struct cftype *files, char *buf,
|
|
ssize_t size, const char *prefix)
|
|
{
|
|
struct cftype *cft;
|
|
ssize_t ret = 0;
|
|
|
|
for (cft = files; cft && cft->name[0] != '\0'; cft++) {
|
|
if (!(cft->flags & CFTYPE_NS_DELEGATABLE))
|
|
continue;
|
|
|
|
if (prefix)
|
|
ret += snprintf(buf + ret, size - ret, "%s.", prefix);
|
|
|
|
ret += snprintf(buf + ret, size - ret, "%s\n", cft->name);
|
|
|
|
if (WARN_ON(ret >= size))
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t delegate_show(struct kobject *kobj, struct kobj_attribute *attr,
|
|
char *buf)
|
|
{
|
|
struct cgroup_subsys *ss;
|
|
int ssid;
|
|
ssize_t ret = 0;
|
|
|
|
ret = show_delegatable_files(cgroup_base_files, buf, PAGE_SIZE - ret,
|
|
NULL);
|
|
|
|
for_each_subsys(ss, ssid)
|
|
ret += show_delegatable_files(ss->dfl_cftypes, buf + ret,
|
|
PAGE_SIZE - ret,
|
|
cgroup_subsys_name[ssid]);
|
|
|
|
return ret;
|
|
}
|
|
static struct kobj_attribute cgroup_delegate_attr = __ATTR_RO(delegate);
|
|
|
|
static ssize_t features_show(struct kobject *kobj, struct kobj_attribute *attr,
|
|
char *buf)
|
|
{
|
|
return snprintf(buf, PAGE_SIZE, "nsdelegate\nmemory_localevents\n");
|
|
}
|
|
static struct kobj_attribute cgroup_features_attr = __ATTR_RO(features);
|
|
|
|
static struct attribute *cgroup_sysfs_attrs[] = {
|
|
&cgroup_delegate_attr.attr,
|
|
&cgroup_features_attr.attr,
|
|
NULL,
|
|
};
|
|
|
|
static const struct attribute_group cgroup_sysfs_attr_group = {
|
|
.attrs = cgroup_sysfs_attrs,
|
|
.name = "cgroup",
|
|
};
|
|
|
|
static int __init cgroup_sysfs_init(void)
|
|
{
|
|
return sysfs_create_group(kernel_kobj, &cgroup_sysfs_attr_group);
|
|
}
|
|
subsys_initcall(cgroup_sysfs_init);
|
|
|
|
#endif /* CONFIG_SYSFS */
|