microsoft
/
WSL2-Linux-Kernel
зеркало из https://github.com/microsoft/WSL2-Linux-Kernel.git
1
0
Форкнуть 0
Код Задачи Пакеты Проекты Релизы Вики Активность

perf: Multiple task contexts 

Provide the infrastructure for multiple task contexts.

A more flexible approach would have resulted in more pointer chases
in the scheduling hot-paths. This approach has the limitation of a
static number of task contexts.

Since I expect most external PMUs to be system wide, or at least node
wide (as per the intel uncore unit) they won't actually need a task
context.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus <paulus@samba.org>
Cc: stephane eranian <eranian@googlemail.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Yanmin <yanmin_zhang@linux.intel.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Peter Zijlstra 2010-09-02 16:50:03 +02:00 коммит произвёл Ingo Molnar
Родитель eb18447987
Коммит 8dc85d5472
3 изменённых файлов: 240 добавлений и 107 удалений
Показать статистику Скачать Patch файл Скачать Diff файл Показать все файлы Свернуть все файлы

1
include/linux/perf_event.h
Просмотреть файл

@ -572,6 +572,7 @@ struct pmu {
int * __percpu pmu_disable_count;
struct perf_cpu_context * __percpu pmu_cpu_context;
int task_ctx_nr;
/*
* Fully disable/enable this PMU, can be used to protect from the PMI

8
include/linux/sched.h
Просмотреть файл

@ -1160,6 +1160,12 @@ struct sched_rt_entity {
struct rcu_node;
enum perf_event_task_context {
perf_invalid_context = -1,
perf_hw_context = 0,
perf_nr_task_contexts,
};
struct task_struct {
volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */
void *stack;
@ -1431,7 +1437,7 @@ struct task_struct {
struct futex_pi_state *pi_state_cache;
#endif
#ifdef CONFIG_PERF_EVENTS
struct perf_event_context *perf_event_ctxp;
struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
struct mutex perf_event_mutex;
struct list_head perf_event_list;
#endif

338
kernel/perf_event.c
Просмотреть файл

@ -148,13 +148,13 @@ static u64 primary_event_id(struct perf_event *event)
* the context could get moved to another task.
*/
static struct perf_event_context *
perf_lock_task_context(struct task_struct *task, unsigned long *flags)
perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
{
struct perf_event_context *ctx;
rcu_read_lock();
retry:
ctx = rcu_dereference(task->perf_event_ctxp);
ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
if (ctx) {
/*
* If this context is a clone of another, it might
@ -167,7 +167,7 @@ retry:
* can't get swapped on us any more.
*/
raw_spin_lock_irqsave(&ctx->lock, *flags);
if (ctx != rcu_dereference(task->perf_event_ctxp)) {
if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
raw_spin_unlock_irqrestore(&ctx->lock, *flags);
goto retry;
}
@ -186,12 +186,13 @@ retry:
* can't get swapped to another task. This also increments its
* reference count so that the context can't get freed.
*/
static struct perf_event_context *perf_pin_task_context(struct task_struct *task)
static struct perf_event_context *
perf_pin_task_context(struct task_struct *task, int ctxn)
{
struct perf_event_context *ctx;
unsigned long flags;
ctx = perf_lock_task_context(task, &flags);
ctx = perf_lock_task_context(task, ctxn, &flags);
if (ctx) {
++ctx->pin_count;
raw_spin_unlock_irqrestore(&ctx->lock, flags);
@ -1179,28 +1180,15 @@ static void perf_event_sync_stat(struct perf_event_context *ctx,
}
}
/*
* Called from scheduler to remove the events of the current task,
* with interrupts disabled.
*
* We stop each event and update the event value in event->count.
*
* This does not protect us against NMI, but disable()
* sets the disabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* not restart the event.
*/
void perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next)
void perf_event_context_sched_out(struct task_struct *task, int ctxn,
struct task_struct *next)
{
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
struct perf_event_context *next_ctx;
struct perf_event_context *parent;
struct perf_cpu_context *cpuctx;
int do_switch = 1;
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
if (likely(!ctx))
return;
@ -1210,7 +1198,7 @@ void perf_event_task_sched_out(struct task_struct *task,
rcu_read_lock();
parent = rcu_dereference(ctx->parent_ctx);
next_ctx = next->perf_event_ctxp;
next_ctx = next->perf_event_ctxp[ctxn];
if (parent && next_ctx &&
rcu_dereference(next_ctx->parent_ctx) == parent) {
/*
@ -1229,8 +1217,8 @@ void perf_event_task_sched_out(struct task_struct *task,
* XXX do we need a memory barrier of sorts
* wrt to rcu_dereference() of perf_event_ctxp
*/
task->perf_event_ctxp = next_ctx;
next->perf_event_ctxp = ctx;
task->perf_event_ctxp[ctxn] = next_ctx;
next->perf_event_ctxp[ctxn] = ctx;
ctx->task = next;
next_ctx->task = task;
do_switch = 0;
@ -1248,6 +1236,31 @@ void perf_event_task_sched_out(struct task_struct *task,
}
}
#define for_each_task_context_nr(ctxn) \
for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
/*
* Called from scheduler to remove the events of the current task,
* with interrupts disabled.
*
* We stop each event and update the event value in event->count.
*
* This does not protect us against NMI, but disable()
* sets the disabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* not restart the event.
*/
void perf_event_task_sched_out(struct task_struct *task,
struct task_struct *next)
{
int ctxn;
perf_sw_event(PERF_COUNT_SW_CONTEXT_SWITCHES, 1, 1, NULL, 0);
for_each_task_context_nr(ctxn)
perf_event_context_sched_out(task, ctxn, next);
}
static void task_ctx_sched_out(struct perf_event_context *ctx,
enum event_type_t event_type)
{
@ -1366,37 +1379,22 @@ static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
ctx_sched_in(ctx, cpuctx, event_type);
}
static void task_ctx_sched_in(struct task_struct *task,
static void task_ctx_sched_in(struct perf_event_context *ctx,
enum event_type_t event_type)
{
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
struct perf_cpu_context *cpuctx;
if (likely(!ctx))
return;
cpuctx = __get_cpu_context(ctx);
if (cpuctx->task_ctx == ctx)
return;
ctx_sched_in(ctx, cpuctx, event_type);
cpuctx->task_ctx = ctx;
}
/*
* Called from scheduler to add the events of the current task
* with interrupts disabled.
*
* We restore the event value and then enable it.
*
* This does not protect us against NMI, but enable()
* sets the enabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* keep the event running.
*/
void perf_event_task_sched_in(struct task_struct *task)
{
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_cpu_context *cpuctx;
if (likely(!ctx))
return;
void perf_event_context_sched_in(struct perf_event_context *ctx)
{
struct perf_cpu_context *cpuctx;
cpuctx = __get_cpu_context(ctx);
if (cpuctx->task_ctx == ctx)
@ -1422,6 +1420,31 @@ void perf_event_task_sched_in(struct task_struct *task)
perf_pmu_rotate_start(ctx->pmu);
}
/*
* Called from scheduler to add the events of the current task
* with interrupts disabled.
*
* We restore the event value and then enable it.
*
* This does not protect us against NMI, but enable()
* sets the enabled bit in the control field of event _before_
* accessing the event control register. If a NMI hits, then it will
* keep the event running.
*/
void perf_event_task_sched_in(struct task_struct *task)
{
struct perf_event_context *ctx;
int ctxn;
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (likely(!ctx))
continue;
perf_event_context_sched_in(ctx);
}
}
#define MAX_INTERRUPTS (~0ULL)
static void perf_log_throttle(struct perf_event *event, int enable);
@ -1588,7 +1611,7 @@ static enum hrtimer_restart perf_event_context_tick(struct hrtimer *timer)
{
enum hrtimer_restart restart = HRTIMER_NORESTART;
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
struct perf_event_context *ctx = NULL;
int rotate = 0;
cpuctx = container_of(timer, struct perf_cpu_context, timer);
@ -1599,7 +1622,7 @@ static enum hrtimer_restart perf_event_context_tick(struct hrtimer *timer)
rotate = 1;
}
ctx = current->perf_event_ctxp;
ctx = cpuctx->task_ctx;
if (ctx && ctx->nr_events) {
restart = HRTIMER_RESTART;
if (ctx->nr_events != ctx->nr_active)
@ -1623,7 +1646,7 @@ static enum hrtimer_restart perf_event_context_tick(struct hrtimer *timer)
cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE);
if (ctx)
task_ctx_sched_in(current, EVENT_FLEXIBLE);
task_ctx_sched_in(ctx, EVENT_FLEXIBLE);
done:
hrtimer_forward_now(timer, ns_to_ktime(cpuctx->timer_interval));
@ -1650,20 +1673,18 @@ static int event_enable_on_exec(struct perf_event *event,
* Enable all of a task's events that have been marked enable-on-exec.
* This expects task == current.
*/
static void perf_event_enable_on_exec(struct task_struct *task)
static void perf_event_enable_on_exec(struct perf_event_context *ctx)
{
struct perf_event_context *ctx;
struct perf_event *event;
unsigned long flags;
int enabled = 0;
int ret;
local_irq_save(flags);
ctx = task->perf_event_ctxp;
if (!ctx || !ctx->nr_events)
goto out;
__perf_event_task_sched_out(ctx);
task_ctx_sched_out(ctx, EVENT_ALL);
raw_spin_lock(&ctx->lock);
@ -1687,7 +1708,7 @@ static void perf_event_enable_on_exec(struct task_struct *task)
raw_spin_unlock(&ctx->lock);
perf_event_task_sched_in(task);
perf_event_context_sched_in(ctx);
out:
local_irq_restore(flags);
}
@ -1995,7 +2016,7 @@ find_get_context(struct pmu *pmu, pid_t pid, int cpu)
struct perf_cpu_context *cpuctx;
struct task_struct *task;
unsigned long flags;
int err;
int ctxn, err;
if (pid == -1 && cpu != -1) {
/* Must be root to operate on a CPU event: */
@ -2044,8 +2065,13 @@ find_get_context(struct pmu *pmu, pid_t pid, int cpu)
if (!ptrace_may_access(task, PTRACE_MODE_READ))
goto errout;
err = -EINVAL;
ctxn = pmu->task_ctx_nr;
if (ctxn < 0)
goto errout;
retry:
ctx = perf_lock_task_context(task, &flags);
ctx = perf_lock_task_context(task, ctxn, &flags);
if (ctx) {
unclone_ctx(ctx);
raw_spin_unlock_irqrestore(&ctx->lock, flags);
@ -2059,7 +2085,7 @@ retry:
get_ctx(ctx);
if (cmpxchg(&task->perf_event_ctxp, NULL, ctx)) {
if (cmpxchg(&task->perf_event_ctxp[ctxn], NULL, ctx)) {
/*
* We raced with some other task; use
* the context they set.
@ -3773,19 +3799,26 @@ static void perf_event_task_ctx(struct perf_event_context *ctx,
static void perf_event_task_event(struct perf_task_event *task_event)
{
struct perf_event_context *ctx = task_event->task_ctx;
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
struct pmu *pmu;
int ctxn;
rcu_read_lock_sched();
list_for_each_entry_rcu(pmu, &pmus, entry) {
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
perf_event_task_ctx(&cpuctx->ctx, task_event);
ctx = task_event->task_ctx;
if (!ctx) {
ctxn = pmu->task_ctx_nr;
if (ctxn < 0)
continue;
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
}
if (ctx)
perf_event_task_ctx(ctx, task_event);
}
if (!ctx)
ctx = rcu_dereference(current->perf_event_ctxp);
if (ctx)
perf_event_task_ctx(ctx, task_event);
rcu_read_unlock_sched();
}
@ -3890,9 +3923,10 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event)
{
struct perf_cpu_context *cpuctx;
struct perf_event_context *ctx;
char comm[TASK_COMM_LEN];
unsigned int size;
struct pmu *pmu;
char comm[TASK_COMM_LEN];
int ctxn;
memset(comm, 0, sizeof(comm));
strlcpy(comm, comm_event->task->comm, sizeof(comm));
@ -3907,19 +3941,31 @@ static void perf_event_comm_event(struct perf_comm_event *comm_event)
list_for_each_entry_rcu(pmu, &pmus, entry) {
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
perf_event_comm_ctx(&cpuctx->ctx, comm_event);
ctxn = pmu->task_ctx_nr;
if (ctxn < 0)
continue;
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
if (ctx)
perf_event_comm_ctx(ctx, comm_event);
}
ctx = rcu_dereference(current->perf_event_ctxp);
if (ctx)
perf_event_comm_ctx(ctx, comm_event);
rcu_read_unlock_sched();
}
void perf_event_comm(struct task_struct *task)
{
struct perf_comm_event comm_event;
struct perf_event_context *ctx;
int ctxn;
if (task->perf_event_ctxp)
perf_event_enable_on_exec(task);
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (!ctx)
continue;
perf_event_enable_on_exec(ctx);
}
if (!atomic_read(&nr_comm_events))
return;
@ -4022,6 +4068,7 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
char *buf = NULL;
const char *name;
struct pmu *pmu;
int ctxn;
memset(tmp, 0, sizeof(tmp));
@ -4078,10 +4125,17 @@ got_name:
cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
perf_event_mmap_ctx(&cpuctx->ctx, mmap_event,
vma->vm_flags & VM_EXEC);
ctxn = pmu->task_ctx_nr;
if (ctxn < 0)
continue;
ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
if (ctx) {
perf_event_mmap_ctx(ctx, mmap_event,
vma->vm_flags & VM_EXEC);
}
}
ctx = rcu_dereference(current->perf_event_ctxp);
if (ctx)
perf_event_mmap_ctx(ctx, mmap_event, vma->vm_flags & VM_EXEC);
rcu_read_unlock_sched();
kfree(buf);
@ -5042,6 +5096,43 @@ static void perf_pmu_cancel_txn(struct pmu *pmu)
perf_pmu_enable(pmu);
}
/*
* Ensures all contexts with the same task_ctx_nr have the same
* pmu_cpu_context too.
*/
static void *find_pmu_context(int ctxn)
{
struct pmu *pmu;
if (ctxn < 0)
return NULL;
list_for_each_entry(pmu, &pmus, entry) {
if (pmu->task_ctx_nr == ctxn)
return pmu->pmu_cpu_context;
}
return NULL;
}
static void free_pmu_context(void * __percpu cpu_context)
{
struct pmu *pmu;
mutex_lock(&pmus_lock);
/*
* Like a real lame refcount.
*/
list_for_each_entry(pmu, &pmus, entry) {
if (pmu->pmu_cpu_context == cpu_context)
goto out;
}
free_percpu(cpu_context);
out:
mutex_unlock(&pmus_lock);
}
int perf_pmu_register(struct pmu *pmu)
{
int cpu, ret;
@ -5052,6 +5143,10 @@ int perf_pmu_register(struct pmu *pmu)
if (!pmu->pmu_disable_count)
goto unlock;
pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
if (pmu->pmu_cpu_context)
goto got_cpu_context;
pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
if (!pmu->pmu_cpu_context)
goto free_pdc;
@ -5067,6 +5162,7 @@ int perf_pmu_register(struct pmu *pmu)
cpuctx->timer.function = perf_event_context_tick;
}
got_cpu_context:
if (!pmu->start_txn) {
if (pmu->pmu_enable) {
/*
@ -5114,7 +5210,7 @@ void perf_pmu_unregister(struct pmu *pmu)
synchronize_srcu(&pmus_srcu);
free_percpu(pmu->pmu_disable_count);
free_percpu(pmu->pmu_cpu_context);
free_pmu_context(pmu->pmu_cpu_context);
}
struct pmu *perf_init_event(struct perf_event *event)
@ -5628,16 +5724,13 @@ __perf_event_exit_task(struct perf_event *child_event,
}
}
/*
* When a child task exits, feed back event values to parent events.
*/
void perf_event_exit_task(struct task_struct *child)
static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
{
struct perf_event *child_event, *tmp;
struct perf_event_context *child_ctx;
unsigned long flags;
if (likely(!child->perf_event_ctxp)) {
if (likely(!child->perf_event_ctxp[ctxn])) {
perf_event_task(child, NULL, 0);
return;
}
@ -5649,7 +5742,7 @@ void perf_event_exit_task(struct task_struct *child)
* scheduled, so we are now safe from rescheduling changing
* our context.
*/
child_ctx = child->perf_event_ctxp;
child_ctx = child->perf_event_ctxp[ctxn];
__perf_event_task_sched_out(child_ctx);
/*
@ -5658,7 +5751,7 @@ void perf_event_exit_task(struct task_struct *child)
* incremented the context's refcount before we do put_ctx below.
*/
raw_spin_lock(&child_ctx->lock);
child->perf_event_ctxp = NULL;
child->perf_event_ctxp[ctxn] = NULL;
/*
* If this context is a clone; unclone it so it can't get
* swapped to another process while we're removing all
@ -5711,6 +5804,17 @@ again:
put_ctx(child_ctx);
}
/*
* When a child task exits, feed back event values to parent events.
*/
void perf_event_exit_task(struct task_struct *child)
{
int ctxn;
for_each_task_context_nr(ctxn)
perf_event_exit_task_context(child, ctxn);
}
static void perf_free_event(struct perf_event *event,
struct perf_event_context *ctx)
{
@ -5732,32 +5836,37 @@ static void perf_free_event(struct perf_event *event,
/*
* free an unexposed, unused context as created by inheritance by
* init_task below, used by fork() in case of fail.
* perf_event_init_task below, used by fork() in case of fail.
*/
void perf_event_free_task(struct task_struct *task)
{
struct perf_event_context *ctx = task->perf_event_ctxp;
struct perf_event_context *ctx;
struct perf_event *event, *tmp;
int ctxn;
if (!ctx)
return;
for_each_task_context_nr(ctxn) {
ctx = task->perf_event_ctxp[ctxn];
if (!ctx)
continue;
mutex_lock(&ctx->mutex);
mutex_lock(&ctx->mutex);
again:
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups, group_entry)
perf_free_event(event, ctx);
list_for_each_entry_safe(event, tmp, &ctx->pinned_groups,
group_entry)
perf_free_event(event, ctx);
list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
group_entry)
perf_free_event(event, ctx);
list_for_each_entry_safe(event, tmp, &ctx->flexible_groups,
group_entry)
perf_free_event(event, ctx);
if (!list_empty(&ctx->pinned_groups) ||
!list_empty(&ctx->flexible_groups))
goto again;
if (!list_empty(&ctx->pinned_groups) ||
!list_empty(&ctx->flexible_groups))
goto again;
mutex_unlock(&ctx->mutex);
mutex_unlock(&ctx->mutex);
put_ctx(ctx);
put_ctx(ctx);
}
}
/*
@ -5863,17 +5972,18 @@ static int inherit_group(struct perf_event *parent_event,
static int
inherit_task_group(struct perf_event *event, struct task_struct *parent,
struct perf_event_context *parent_ctx,
struct task_struct *child,
struct task_struct *child, int ctxn,
int *inherited_all)
{
int ret;
struct perf_event_context *child_ctx = child->perf_event_ctxp;
struct perf_event_context *child_ctx;
if (!event->attr.inherit) {
*inherited_all = 0;
return 0;
}
child_ctx = child->perf_event_ctxp[ctxn];
if (!child_ctx) {
/*
* This is executed from the parent task context, so
@ -5886,7 +5996,7 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent,
if (!child_ctx)
return -ENOMEM;
child->perf_event_ctxp = child_ctx;
child->perf_event_ctxp[ctxn] = child_ctx;
}
ret = inherit_group(event, parent, parent_ctx,
@ -5901,7 +6011,7 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent,
/*
* Initialize the perf_event context in task_struct
*/
int perf_event_init_task(struct task_struct *child)
int perf_event_init_context(struct task_struct *child, int ctxn)
{
struct perf_event_context *child_ctx, *parent_ctx;
struct perf_event_context *cloned_ctx;
@ -5910,19 +6020,19 @@ int perf_event_init_task(struct task_struct *child)
int inherited_all = 1;
int ret = 0;
child->perf_event_ctxp = NULL;
child->perf_event_ctxp[ctxn] = NULL;
mutex_init(&child->perf_event_mutex);
INIT_LIST_HEAD(&child->perf_event_list);
if (likely(!parent->perf_event_ctxp))
if (likely(!parent->perf_event_ctxp[ctxn]))
return 0;
/*
* If the parent's context is a clone, pin it so it won't get
* swapped under us.
*/
parent_ctx = perf_pin_task_context(parent);
parent_ctx = perf_pin_task_context(parent, ctxn);
/*
* No need to check if parent_ctx != NULL here; since we saw
@ -5942,20 +6052,20 @@ int perf_event_init_task(struct task_struct *child)
* the list, not manipulating it:
*/
list_for_each_entry(event, &parent_ctx->pinned_groups, group_entry) {
ret = inherit_task_group(event, parent, parent_ctx, child,
&inherited_all);
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
if (ret)
break;
}
list_for_each_entry(event, &parent_ctx->flexible_groups, group_entry) {
ret = inherit_task_group(event, parent, parent_ctx, child,
&inherited_all);
ret = inherit_task_group(event, parent, parent_ctx,
child, ctxn, &inherited_all);
if (ret)
break;
}
child_ctx = child->perf_event_ctxp;
child_ctx = child->perf_event_ctxp[ctxn];
if (child_ctx && inherited_all) {
/*
@ -5984,6 +6094,22 @@ int perf_event_init_task(struct task_struct *child)
return ret;
}
/*
* Initialize the perf_event context in task_struct
*/
int perf_event_init_task(struct task_struct *child)
{
int ctxn, ret;
for_each_task_context_nr(ctxn) {
ret = perf_event_init_context(child, ctxn);
if (ret)
return ret;
}
return 0;
}
static void __init perf_event_init_all_cpus(void)
{
struct swevent_htable *swhash;