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perf/core: Collapse common IPI pattern

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Various functions implement the same pattern to send IPIs to an
event's CPU. Collapse the easy ones in a common helper function to
reduce duplication.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2015-11-30 16:26:35 +01:00 committed by Ingo Molnar
parent 42a0789bf5
commit 0017960f38
1 changed files with 76 additions and 104 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

180
kernel/events/core.c
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@ -126,6 +126,37 @@ static int cpu_function_call(int cpu, remote_function_f func, void *info)
return data.ret;
}
static void event_function_call(struct perf_event *event,
int (*active)(void *),
void (*inactive)(void *),
void *data)
{
struct perf_event_context *ctx = event->ctx;
struct task_struct *task = ctx->task;
if (!task) {
cpu_function_call(event->cpu, active, data);
return;
}
again:
if (!task_function_call(task, active, data))
return;
raw_spin_lock_irq(&ctx->lock);
if (ctx->is_active) {
/*
* Reload the task pointer, it might have been changed by
* a concurrent perf_event_context_sched_out().
*/
task = ctx->task;
raw_spin_unlock_irq(&ctx->lock);
goto again;
}
inactive(data);
raw_spin_unlock_irq(&ctx->lock);
}
#define EVENT_OWNER_KERNEL ((void *) -1)
static bool is_kernel_event(struct perf_event *event)
@ -1629,6 +1660,17 @@ struct remove_event {
bool detach_group;
};
static void ___perf_remove_from_context(void *info)
{
struct remove_event *re = info;
struct perf_event *event = re->event;
struct perf_event_context *ctx = event->ctx;
if (re->detach_group)
perf_group_detach(event);
list_del_event(event, ctx);
}
/*
* Cross CPU call to remove a performance event
*
@ -1656,7 +1698,6 @@ static int __perf_remove_from_context(void *info)
return 0;
}
/*
* Remove the event from a task's (or a CPU's) list of events.
*
@ -1673,7 +1714,6 @@ static int __perf_remove_from_context(void *info)
static void perf_remove_from_context(struct perf_event *event, bool detach_group)
{
struct perf_event_context *ctx = event->ctx;
struct task_struct *task = ctx->task;
struct remove_event re = {
.event = event,
.detach_group = detach_group,
@ -1681,44 +1721,8 @@ static void perf_remove_from_context(struct perf_event *event, bool detach_group
lockdep_assert_held(&ctx->mutex);
if (!task) {
/*
* Per cpu events are removed via an smp call. The removal can
* fail if the CPU is currently offline, but in that case we
* already called __perf_remove_from_context from
* perf_event_exit_cpu.
*/
cpu_function_call(event->cpu, __perf_remove_from_context, &re);
return;
}
retry:
if (!task_function_call(task, __perf_remove_from_context, &re))
return;
raw_spin_lock_irq(&ctx->lock);
/*
* If we failed to find a running task, but find the context active now
* that we've acquired the ctx->lock, retry.
*/
if (ctx->is_active) {
raw_spin_unlock_irq(&ctx->lock);
/*
* Reload the task pointer, it might have been changed by
* a concurrent perf_event_context_sched_out().
*/
task = ctx->task;
goto retry;
}
/*
* Since the task isn't running, its safe to remove the event, us
* holding the ctx->lock ensures the task won't get scheduled in.
*/
if (detach_group)
perf_group_detach(event);
list_del_event(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
event_function_call(event, __perf_remove_from_context,
___perf_remove_from_context, &re);
}
/*
@ -2067,6 +2071,18 @@ static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
}
static void ___perf_install_in_context(void *info)
{
struct perf_event *event = info;
struct perf_event_context *ctx = event->ctx;
/*
* Since the task isn't running, its safe to add the event, us holding
* the ctx->lock ensures the task won't get scheduled in.
*/
add_event_to_ctx(event, ctx);
}
/*
* Cross CPU call to install and enable a performance event
*
@ -2143,48 +2159,14 @@ perf_install_in_context(struct perf_event_context *ctx,
struct perf_event *event,
int cpu)
{
struct task_struct *task = ctx->task;
lockdep_assert_held(&ctx->mutex);
event->ctx = ctx;
if (event->cpu != -1)
event->cpu = cpu;
if (!task) {
/*
* Per cpu events are installed via an smp call and
* the install is always successful.
*/
cpu_function_call(cpu, __perf_install_in_context, event);
return;
}
retry:
if (!task_function_call(task, __perf_install_in_context, event))
return;
raw_spin_lock_irq(&ctx->lock);
/*
* If we failed to find a running task, but find the context active now
* that we've acquired the ctx->lock, retry.
*/
if (ctx->is_active) {
raw_spin_unlock_irq(&ctx->lock);
/*
* Reload the task pointer, it might have been changed by
* a concurrent perf_event_context_sched_out().
*/
task = ctx->task;
goto retry;
}
/*
* Since the task isn't running, its safe to add the event, us holding
* the ctx->lock ensures the task won't get scheduled in.
*/
add_event_to_ctx(event, ctx);
raw_spin_unlock_irq(&ctx->lock);
event_function_call(event, __perf_install_in_context,
___perf_install_in_context, event);
}
/*
@ -4154,6 +4136,22 @@ struct period_event {
u64 value;
};
static void ___perf_event_period(void *info)
{
struct period_event *pe = info;
struct perf_event *event = pe->event;
u64 value = pe->value;
if (event->attr.freq) {
event->attr.sample_freq = value;
} else {
event->attr.sample_period = value;
event->hw.sample_period = value;
}
local64_set(&event->hw.period_left, 0);
}
static int __perf_event_period(void *info)
{
struct period_event *pe = info;
@ -4190,8 +4188,6 @@ static int __perf_event_period(void *info)
static int perf_event_period(struct perf_event *event, u64 __user *arg)
{
struct period_event pe = { .event = event, };
struct perf_event_context *ctx = event->ctx;
struct task_struct *task;
u64 value;
if (!is_sampling_event(event))
@ -4206,34 +4202,10 @@ static int perf_event_period(struct perf_event *event, u64 __user *arg)
if (event->attr.freq && value > sysctl_perf_event_sample_rate)
return -EINVAL;
task = ctx->task;
pe.value = value;
if (!task) {
cpu_function_call(event->cpu, __perf_event_period, &pe);
return 0;
}
retry:
if (!task_function_call(task, __perf_event_period, &pe))
return 0;
raw_spin_lock_irq(&ctx->lock);
if (ctx->is_active) {
raw_spin_unlock_irq(&ctx->lock);
task = ctx->task;
goto retry;
}
if (event->attr.freq) {
event->attr.sample_freq = value;
} else {
event->attr.sample_period = value;
event->hw.sample_period = value;
}
local64_set(&event->hw.period_left, 0);
raw_spin_unlock_irq(&ctx->lock);
event_function_call(event, __perf_event_period,
___perf_event_period, &pe);
return 0;
}