146 lines
5.1 KiB
C
146 lines
5.1 KiB
C
/*
|
|
* Sleepable Read-Copy Update mechanism for mutual exclusion,
|
|
* tree variant.
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This program is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, you can access it online at
|
|
* http://www.gnu.org/licenses/gpl-2.0.html.
|
|
*
|
|
* Copyright (C) IBM Corporation, 2017
|
|
*
|
|
* Author: Paul McKenney <paulmck@us.ibm.com>
|
|
*/
|
|
|
|
#ifndef _LINUX_SRCU_TREE_H
|
|
#define _LINUX_SRCU_TREE_H
|
|
|
|
#include <linux/rcu_node_tree.h>
|
|
#include <linux/completion.h>
|
|
|
|
struct srcu_node;
|
|
struct srcu_struct;
|
|
|
|
/*
|
|
* Per-CPU structure feeding into leaf srcu_node, similar in function
|
|
* to rcu_node.
|
|
*/
|
|
struct srcu_data {
|
|
/* Read-side state. */
|
|
unsigned long srcu_lock_count[2]; /* Locks per CPU. */
|
|
unsigned long srcu_unlock_count[2]; /* Unlocks per CPU. */
|
|
|
|
/* Update-side state. */
|
|
raw_spinlock_t __private lock ____cacheline_internodealigned_in_smp;
|
|
struct rcu_segcblist srcu_cblist; /* List of callbacks.*/
|
|
unsigned long srcu_gp_seq_needed; /* Furthest future GP needed. */
|
|
unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */
|
|
bool srcu_cblist_invoking; /* Invoking these CBs? */
|
|
struct delayed_work work; /* Context for CB invoking. */
|
|
struct rcu_head srcu_barrier_head; /* For srcu_barrier() use. */
|
|
struct srcu_node *mynode; /* Leaf srcu_node. */
|
|
unsigned long grpmask; /* Mask for leaf srcu_node */
|
|
/* ->srcu_data_have_cbs[]. */
|
|
int cpu;
|
|
struct srcu_struct *sp;
|
|
};
|
|
|
|
/*
|
|
* Node in SRCU combining tree, similar in function to rcu_data.
|
|
*/
|
|
struct srcu_node {
|
|
raw_spinlock_t __private lock;
|
|
unsigned long srcu_have_cbs[4]; /* GP seq for children */
|
|
/* having CBs, but only */
|
|
/* is > ->srcu_gq_seq. */
|
|
unsigned long srcu_data_have_cbs[4]; /* Which srcu_data structs */
|
|
/* have CBs for given GP? */
|
|
unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */
|
|
struct srcu_node *srcu_parent; /* Next up in tree. */
|
|
int grplo; /* Least CPU for node. */
|
|
int grphi; /* Biggest CPU for node. */
|
|
};
|
|
|
|
/*
|
|
* Per-SRCU-domain structure, similar in function to rcu_state.
|
|
*/
|
|
struct srcu_struct {
|
|
struct srcu_node node[NUM_RCU_NODES]; /* Combining tree. */
|
|
struct srcu_node *level[RCU_NUM_LVLS + 1];
|
|
/* First node at each level. */
|
|
struct mutex srcu_cb_mutex; /* Serialize CB preparation. */
|
|
raw_spinlock_t __private lock; /* Protect counters */
|
|
struct mutex srcu_gp_mutex; /* Serialize GP work. */
|
|
unsigned int srcu_idx; /* Current rdr array element. */
|
|
unsigned long srcu_gp_seq; /* Grace-period seq #. */
|
|
unsigned long srcu_gp_seq_needed; /* Latest gp_seq needed. */
|
|
unsigned long srcu_gp_seq_needed_exp; /* Furthest future exp GP. */
|
|
unsigned long srcu_last_gp_end; /* Last GP end timestamp (ns) */
|
|
struct srcu_data __percpu *sda; /* Per-CPU srcu_data array. */
|
|
unsigned long srcu_barrier_seq; /* srcu_barrier seq #. */
|
|
struct mutex srcu_barrier_mutex; /* Serialize barrier ops. */
|
|
struct completion srcu_barrier_completion;
|
|
/* Awaken barrier rq at end. */
|
|
atomic_t srcu_barrier_cpu_cnt; /* # CPUs not yet posting a */
|
|
/* callback for the barrier */
|
|
/* operation. */
|
|
struct delayed_work work;
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
struct lockdep_map dep_map;
|
|
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
|
|
};
|
|
|
|
/* Values for state variable (bottom bits of ->srcu_gp_seq). */
|
|
#define SRCU_STATE_IDLE 0
|
|
#define SRCU_STATE_SCAN1 1
|
|
#define SRCU_STATE_SCAN2 2
|
|
|
|
void process_srcu(struct work_struct *work);
|
|
|
|
#define __SRCU_STRUCT_INIT(name) \
|
|
{ \
|
|
.sda = &name##_srcu_data, \
|
|
.lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
|
|
.srcu_gp_seq_needed = 0 - 1, \
|
|
__SRCU_DEP_MAP_INIT(name) \
|
|
}
|
|
|
|
/*
|
|
* Define and initialize a srcu struct at build time.
|
|
* Do -not- call init_srcu_struct() nor cleanup_srcu_struct() on it.
|
|
*
|
|
* Note that although DEFINE_STATIC_SRCU() hides the name from other
|
|
* files, the per-CPU variable rules nevertheless require that the
|
|
* chosen name be globally unique. These rules also prohibit use of
|
|
* DEFINE_STATIC_SRCU() within a function. If these rules are too
|
|
* restrictive, declare the srcu_struct manually. For example, in
|
|
* each file:
|
|
*
|
|
* static struct srcu_struct my_srcu;
|
|
*
|
|
* Then, before the first use of each my_srcu, manually initialize it:
|
|
*
|
|
* init_srcu_struct(&my_srcu);
|
|
*
|
|
* See include/linux/percpu-defs.h for the rules on per-CPU variables.
|
|
*/
|
|
#define __DEFINE_SRCU(name, is_static) \
|
|
static DEFINE_PER_CPU(struct srcu_data, name##_srcu_data);\
|
|
is_static struct srcu_struct name = __SRCU_STRUCT_INIT(name)
|
|
#define DEFINE_SRCU(name) __DEFINE_SRCU(name, /* not static */)
|
|
#define DEFINE_STATIC_SRCU(name) __DEFINE_SRCU(name, static)
|
|
|
|
void synchronize_srcu_expedited(struct srcu_struct *sp);
|
|
void srcu_barrier(struct srcu_struct *sp);
|
|
|
|
#endif
|