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Subject[PATCH 10/12] perf: Fix scaling vs perf_event_enable
Similar to the perf_enable_on_exec(), ensure that event timings are
consistent across perf_event_enable().

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
kernel/events/core.c | 42 +++++++++++++++++++++++-------------------
1 file changed, 23 insertions(+), 19 deletions(-)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2069,14 +2069,27 @@ static void add_event_to_ctx(struct perf
event->tstamp_stopped = tstamp;
}

-static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx);
+static void ctx_sched_out(struct perf_event_context *ctx,
+ struct perf_cpu_context *cpuctx,
+ enum event_type_t event_type);
static void
ctx_sched_in(struct perf_event_context *ctx,
struct perf_cpu_context *cpuctx,
enum event_type_t event_type,
struct task_struct *task);

+static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
+ struct perf_event_context *ctx)
+{
+ if (!cpuctx->task_ctx)
+ return;
+
+ if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
+ return;
+
+ ctx_sched_out(ctx, cpuctx, EVENT_ALL);
+}
+
static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
struct perf_event_context *ctx,
struct task_struct *task)
@@ -2227,17 +2240,18 @@ static void __perf_event_enable(struct p
event->state <= PERF_EVENT_STATE_ERROR)
return;

- update_context_time(ctx);
+ if (ctx->is_active)
+ ctx_sched_out(ctx, cpuctx, EVENT_TIME);
+
__perf_event_mark_enabled(event);

if (!ctx->is_active)
return;

if (!event_filter_match(event)) {
- if (is_cgroup_event(event)) {
- perf_cgroup_set_timestamp(current, ctx); // XXX ?
+ if (is_cgroup_event(event))
perf_cgroup_defer_enabled(event);
- }
+ ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
return;
}

@@ -2245,8 +2259,10 @@ static void __perf_event_enable(struct p
* If the event is in a group and isn't the group leader,
* then don't put it on unless the group is on.
*/
- if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
+ if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
+ ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
return;
+ }

task_ctx = cpuctx->task_ctx;
if (ctx->task)
@@ -2658,18 +2674,6 @@ void __perf_event_task_sched_out(struct
perf_cgroup_sched_out(task, next);
}

-static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
- struct perf_event_context *ctx)
-{
- if (!cpuctx->task_ctx)
- return;
-
- if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
- return;
-
- ctx_sched_out(ctx, cpuctx, EVENT_ALL);
-}
-
/*
* Called with IRQs disabled
*/

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