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x86/intel_rdt: Add cpus file 

Now we populate each directory with a read/write (mode 0644) file
named "cpus". This is used to over-ride the resources available
to processes in the default resource group when running on specific
CPUs.  Each "cpus" file reads as a cpumask showing which CPUs belong
to this resource group. Initially all online CPUs are assigned to
the default group. They can be added to other groups by writing a
cpumask to the "cpus" file in the directory for the resource group
(which will remove them from the previous group to which they were
assigned). CPU online/offline operations will delete CPUs that go
offline from whatever group they are in and add new CPUs to the
default group.

If there are CPUs assigned to a group when the directory is removed,
they are returned to the default group.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "Shaohua Li" <shli@fb.com>
Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: "Stephane Eranian" <eranian@google.com>
Cc: "Dave Hansen" <dave.hansen@intel.com>
Cc: "David Carrillo-Cisneros" <davidcc@google.com>
Cc: "Nilay Vaish" <nilayvaish@gmail.com>
Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com>
Cc: "Ingo Molnar" <mingo@elte.hu>
Cc: "Borislav Petkov" <bp@suse.de>
Cc: "H. Peter Anvin" <h.peter.anvin@intel.com>
Link: http://lkml.kernel.org/r/1477692289-37412-7-git-send-email-fenghua.yu@intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Tony Luck 2016-10-28 15:04:45 -07:00 committed by Thomas Gleixner
parent 60cf5e101f
commit 12e0110c11
3 changed files with 154 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
arch/x86/include/asm/intel_rdt.h
View File

@ -14,13 +14,16 @@
* @kn: kernfs node
* @rdtgroup_list: linked list for all rdtgroups
* @closid: closid for this rdtgroup
* @cpu_mask: CPUs assigned to this rdtgroup
* @flags: status bits
* @waitcount: how many cpus expect to find this
* group when they acquire rdtgroup_mutex
*/
struct rdtgroup {
struct kernfs_node *kn;
struct list_head rdtgroup_list;
int closid;
struct cpumask cpu_mask;
int flags;
atomic_t waitcount;
};
@ -162,6 +165,8 @@ union cpuid_0x10_1_edx {
unsigned int full;
};
DECLARE_PER_CPU_READ_MOSTLY(int, cpu_closid);
void rdt_cbm_update(void *arg);
struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn);
void rdtgroup_kn_unlock(struct kernfs_node *kn);

23
arch/x86/kernel/cpu/intel_rdt.c
View File

@ -36,6 +36,8 @@
/* Mutex to protect rdtgroup access. */
DEFINE_MUTEX(rdtgroup_mutex);
DEFINE_PER_CPU_READ_MOSTLY(int, cpu_closid);
#define domain_init(id) LIST_HEAD_INIT(rdt_resources_all[id].domains)
struct rdt_resource rdt_resources_all[] = {
@ -331,16 +333,25 @@ static void domain_remove_cpu(int cpu, struct rdt_resource *r)
}
}
static int intel_rdt_online_cpu(unsigned int cpu)
static void clear_closid(int cpu)
{
struct intel_pqr_state *state = this_cpu_ptr(&pqr_state);
per_cpu(cpu_closid, cpu) = 0;
state->closid = 0;
wrmsr(MSR_IA32_PQR_ASSOC, state->rmid, 0);
}
static int intel_rdt_online_cpu(unsigned int cpu)
{
struct rdt_resource *r;
mutex_lock(&rdtgroup_mutex);
for_each_capable_rdt_resource(r)
domain_add_cpu(cpu, r);
state->closid = 0;
wrmsr(MSR_IA32_PQR_ASSOC, state->rmid, 0);
/* The cpu is set in default rdtgroup after online. */
cpumask_set_cpu(cpu, &rdtgroup_default.cpu_mask);
clear_closid(cpu);
mutex_unlock(&rdtgroup_mutex);
return 0;
@ -348,11 +359,17 @@ static int intel_rdt_online_cpu(unsigned int cpu)
static int intel_rdt_offline_cpu(unsigned int cpu)
{
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
mutex_lock(&rdtgroup_mutex);
for_each_capable_rdt_resource(r)
domain_remove_cpu(cpu, r);
list_for_each_entry(rdtgrp, &rdt_all_groups, rdtgroup_list) {
if (cpumask_test_and_clear_cpu(cpu, &rdtgrp->cpu_mask))
break;
}
clear_closid(cpu);
mutex_unlock(&rdtgroup_mutex);
return 0;

131
arch/x86/kernel/cpu/intel_rdt_rdtgroup.c
View File

@ -20,6 +20,7 @@
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/cpu.h>
#include <linux/fs.h>
#include <linux/sysfs.h>
#include <linux/kernfs.h>
@ -172,6 +173,111 @@ static struct kernfs_ops rdtgroup_kf_single_ops = {
.seq_show = rdtgroup_seqfile_show,
};
static int rdtgroup_cpus_show(struct kernfs_open_file *of,
struct seq_file *s, void *v)
{
struct rdtgroup *rdtgrp;
int ret = 0;
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (rdtgrp)
seq_printf(s, "%*pb\n", cpumask_pr_args(&rdtgrp->cpu_mask));
else
ret = -ENOENT;
rdtgroup_kn_unlock(of->kn);
return ret;
}
static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
cpumask_var_t tmpmask, newmask;
struct rdtgroup *rdtgrp, *r;
int ret, cpu;
if (!buf)
return -EINVAL;
if (!zalloc_cpumask_var(&tmpmask, GFP_KERNEL))
return -ENOMEM;
if (!zalloc_cpumask_var(&newmask, GFP_KERNEL)) {
free_cpumask_var(tmpmask);
return -ENOMEM;
}
rdtgrp = rdtgroup_kn_lock_live(of->kn);
if (!rdtgrp) {
ret = -ENOENT;
goto unlock;
}
ret = cpumask_parse(buf, newmask);
if (ret)
goto unlock;
get_online_cpus();
/* check that user didn't specify any offline cpus */
cpumask_andnot(tmpmask, newmask, cpu_online_mask);
if (cpumask_weight(tmpmask)) {
ret = -EINVAL;
goto end;
}
/* Check whether cpus are dropped from this group */
cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);
if (cpumask_weight(tmpmask)) {
/* Can't drop from default group */
if (rdtgrp == &rdtgroup_default) {
ret = -EINVAL;
goto end;
}
/* Give any dropped cpus to rdtgroup_default */
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, tmpmask);
for_each_cpu(cpu, tmpmask)
per_cpu(cpu_closid, cpu) = 0;
}
/*
* If we added cpus, remove them from previous group that owned them
* and update per-cpu closid
*/
cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);
if (cpumask_weight(tmpmask)) {
list_for_each_entry(r, &rdt_all_groups, rdtgroup_list) {
if (r == rdtgrp)
continue;
cpumask_andnot(&r->cpu_mask, &r->cpu_mask, tmpmask);
}
for_each_cpu(cpu, tmpmask)
per_cpu(cpu_closid, cpu) = rdtgrp->closid;
}
/* Done pushing/pulling - update this group with new mask */
cpumask_copy(&rdtgrp->cpu_mask, newmask);
end:
put_online_cpus();
unlock:
rdtgroup_kn_unlock(of->kn);
free_cpumask_var(tmpmask);
free_cpumask_var(newmask);
return ret ?: nbytes;
}
/* Files in each rdtgroup */
static struct rftype rdtgroup_base_files[] = {
{
.name = "cpus",
.mode = 0644,
.kf_ops = &rdtgroup_kf_single_ops,
.write = rdtgroup_cpus_write,
.seq_show = rdtgroup_cpus_show,
},
};
static int rdt_num_closids_show(struct kernfs_open_file *of,
struct seq_file *seq, void *v)
{
@ -582,6 +688,11 @@ static int rdtgroup_mkdir(struct kernfs_node *parent_kn, const char *name,
if (ret)
goto out_destroy;
ret = rdtgroup_add_files(kn, rdtgroup_base_files,
ARRAY_SIZE(rdtgroup_base_files));
if (ret)
goto out_destroy;
kernfs_activate(kn);
ret = 0;
@ -602,7 +713,7 @@ out_unlock:
static int rdtgroup_rmdir(struct kernfs_node *kn)
{
struct rdtgroup *rdtgrp;
int ret = 0;
int cpu, ret = 0;
rdtgrp = rdtgroup_kn_lock_live(kn);
if (!rdtgrp) {
@ -610,6 +721,12 @@ static int rdtgroup_rmdir(struct kernfs_node *kn)
return -ENOENT;
}
/* Give any CPUs back to the default group */
cpumask_or(&rdtgroup_default.cpu_mask,
&rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask);
for_each_cpu(cpu, &rdtgrp->cpu_mask)
per_cpu(cpu_closid, cpu) = 0;
rdtgrp->flags = RDT_DELETED;
closid_free(rdtgrp->closid);
list_del(&rdtgrp->rdtgroup_list);
@ -633,6 +750,8 @@ static struct kernfs_syscall_ops rdtgroup_kf_syscall_ops = {
static int __init rdtgroup_setup_root(void)
{
int ret;
rdt_root = kernfs_create_root(&rdtgroup_kf_syscall_ops,
KERNFS_ROOT_CREATE_DEACTIVATED,
&rdtgroup_default);
@ -644,12 +763,20 @@ static int __init rdtgroup_setup_root(void)
rdtgroup_default.closid = 0;
list_add(&rdtgroup_default.rdtgroup_list, &rdt_all_groups);
ret = rdtgroup_add_files(rdt_root->kn, rdtgroup_base_files,
ARRAY_SIZE(rdtgroup_base_files));
if (ret) {
kernfs_destroy_root(rdt_root);
goto out;
}
rdtgroup_default.kn = rdt_root->kn;
kernfs_activate(rdtgroup_default.kn);
out:
mutex_unlock(&rdtgroup_mutex);
return 0;
return ret;
}
/*