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perf: Simplify/fix perf_event_enable() event scheduling 

Like perf_enable_on_exec(), perf_event_enable() event scheduling has problems
respecting the context hierarchy when trying to schedule events (for
example, it will try and add a pinned event without first removing
existing flexible events).

So simplify it by using the new ctx_resched() call which will DTRT.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
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 2016-01-08 10:45:11 +01:00 committed by Ingo Molnar
parent 8833d0e286
commit aee7dbc45f
1 changed files with 5 additions and 26 deletions
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31
kernel/events/core.c
View File

@ -2188,7 +2188,7 @@ static int __perf_event_enable(void *info)
struct perf_event_context *ctx = event->ctx;
struct perf_event *leader = event->group_leader;
struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
int err;
struct perf_event_context *task_ctx = cpuctx->task_ctx;
/*
* There's a time window between 'ctx->is_active' check
@ -2202,7 +2202,8 @@ static int __perf_event_enable(void *info)
if (!ctx->is_active)
return -EINVAL;
raw_spin_lock(&ctx->lock);
perf_ctx_lock(cpuctx, task_ctx);
WARN_ON_ONCE(&cpuctx->ctx != ctx && task_ctx != ctx);
update_context_time(ctx);
if (event->state >= PERF_EVENT_STATE_INACTIVE)
@ -2228,32 +2229,10 @@ static int __perf_event_enable(void *info)
if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE)
goto unlock;
if (!group_can_go_on(event, cpuctx, 1)) {
err = -EEXIST;
} else {
if (event == leader)
err = group_sched_in(event, cpuctx, ctx);
else
err = event_sched_in(event, cpuctx, ctx);
}
if (err) {
/*
* If this event can't go on and it's part of a
* group, then the whole group has to come off.
*/
if (leader != event) {
group_sched_out(leader, cpuctx, ctx);
perf_mux_hrtimer_restart(cpuctx);
}
if (leader->attr.pinned) {
update_group_times(leader);
leader->state = PERF_EVENT_STATE_ERROR;
}
}
ctx_resched(cpuctx, task_ctx);
unlock:
raw_spin_unlock(&ctx->lock);
perf_ctx_unlock(cpuctx, task_ctx);
return 0;
}