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Commit 9ffcfa6f authored by Stephane Eranian's avatar Stephane Eranian Committed by Ingo Molnar
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perf_events: Revert: Fix transaction recovery in group_sched_in() 



This patch reverts commit 8e5fc1a7 (perf_events: Fix transaction
recovery in group_sched_in()) because it had one flaw in case the
group could never be scheduled. It would cause time_enabled to get
negative.

Signed-off-by: default avatarStephane Eranian <eranian@google.com>
Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <4cbeeeb7.0aefd80a.6e40.0e2f@mx.google.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 96681fc3

kernel/perf_event.c

+13 −63
Original line number Diff line number Diff line
@@ -417,8 +417,8 @@ event_filter_match(struct perf_event *event) 
	return event->cpu == -1 || event->cpu == smp_processor_id();

}



static int

__event_sched_out(struct perf_event *event,

static void

event_sched_out(struct perf_event *event,

		  struct perf_cpu_context *cpuctx,

		  struct perf_event_context *ctx)

{
@@ -437,13 +437,14 @@ __event_sched_out(struct perf_event *event, 
	}



	if (event->state != PERF_EVENT_STATE_ACTIVE)

		return 0;

		return;



	event->state = PERF_EVENT_STATE_INACTIVE;

	if (event->pending_disable) {

		event->pending_disable = 0;

		event->state = PERF_EVENT_STATE_OFF;

	}

	event->tstamp_stopped = ctx->time;

	event->pmu->del(event, 0);

	event->oncpu = -1;
@@ -452,19 +453,6 @@ __event_sched_out(struct perf_event *event, 
	ctx->nr_active--;

	if (event->attr.exclusive || !cpuctx->active_oncpu)

		cpuctx->exclusive = 0;

	return 1;

}



static void

event_sched_out(struct perf_event *event,

		  struct perf_cpu_context *cpuctx,

		  struct perf_event_context *ctx)

{

	int ret;



	ret = __event_sched_out(event, cpuctx, ctx);

	if (ret)

		event->tstamp_stopped = ctx->time;

}



static void
@@ -664,7 +652,7 @@ void perf_event_disable(struct perf_event *event) 
}



static int

__event_sched_in(struct perf_event *event,

event_sched_in(struct perf_event *event,

		 struct perf_cpu_context *cpuctx,

		 struct perf_event_context *ctx)

{
@@ -684,6 +672,8 @@ __event_sched_in(struct perf_event *event, 
		return -EAGAIN;

	}



	event->tstamp_running += ctx->time - event->tstamp_stopped;



	if (!is_software_event(event))

		cpuctx->active_oncpu++;

	ctx->nr_active++;
@@ -694,35 +684,6 @@ __event_sched_in(struct perf_event *event, 
	return 0;

}



static inline int

event_sched_in(struct perf_event *event,

		 struct perf_cpu_context *cpuctx,

		 struct perf_event_context *ctx)

{

	int ret = __event_sched_in(event, cpuctx, ctx);

	if (ret)

		return ret;

	event->tstamp_running += ctx->time - event->tstamp_stopped;

	return 0;

}



static void

group_commit_event_sched_in(struct perf_event *group_event,

	       struct perf_cpu_context *cpuctx,

	       struct perf_event_context *ctx)

{

	struct perf_event *event;

	u64 now = ctx->time;



	group_event->tstamp_running += now - group_event->tstamp_stopped;

	/*

	 * Schedule in siblings as one group (if any):

	 */

	list_for_each_entry(event, &group_event->sibling_list, group_entry) {

		event->tstamp_running += now - event->tstamp_stopped;

	}

}



static int

group_sched_in(struct perf_event *group_event,

	       struct perf_cpu_context *cpuctx,
@@ -736,13 +697,7 @@ group_sched_in(struct perf_event *group_event, 


	pmu->start_txn(pmu);



	/*

	 * use __event_sched_in() to delay updating tstamp_running

	 * until the transaction is committed. In case of failure

	 * we will keep an unmodified tstamp_running which is a

	 * requirement to get correct timing information

	 */

	if (__event_sched_in(group_event, cpuctx, ctx)) {

	if (event_sched_in(group_event, cpuctx, ctx)) {

		pmu->cancel_txn(pmu);

		return -EAGAIN;

	}
@@ -751,31 +706,26 @@ group_sched_in(struct perf_event *group_event, 
	 * Schedule in siblings as one group (if any):

	 */

	list_for_each_entry(event, &group_event->sibling_list, group_entry) {

		if (__event_sched_in(event, cpuctx, ctx)) {

		if (event_sched_in(event, cpuctx, ctx)) {

			partial_group = event;

			goto group_error;

		}

	}



	if (!pmu->commit_txn(pmu)) {

		/* commit tstamp_running */

		group_commit_event_sched_in(group_event, cpuctx, ctx);

	if (!pmu->commit_txn(pmu))

		return 0;

	}



group_error:

	/*

	 * Groups can be scheduled in as one unit only, so undo any

	 * partial group before returning:

	 *

	 * use __event_sched_out() to avoid updating tstamp_stopped

	 * because the event never actually ran

	 */

	list_for_each_entry(event, &group_event->sibling_list, group_entry) {

		if (event == partial_group)

			break;

		__event_sched_out(event, cpuctx, ctx);

		event_sched_out(event, cpuctx, ctx);

	}

	__event_sched_out(group_event, cpuctx, ctx);

	event_sched_out(group_event, cpuctx, ctx);



	pmu->cancel_txn(pmu);