Commit-ID: 0017960f38a2470e70d9f1991228e2b55b2abe0c
Gitweb: http://git.kernel.org/tip/0017960f38a2470e70d9f1991228e2b55b2abe0c
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Mon, 30 Nov 2015 16:26:35 +0100
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Sun, 6 Dec 2015 12:55:48 +0100
perf/core: Collapse common IPI pattern
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@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 180 ++++++++++++++++++++++-----------------------------
1 file changed, 76 insertions(+), 104 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 39cf4a4..c3d61b9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -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;
}
--
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