On Wed, Dec 11, 2013 at 02:36:13PM +0200, Alexander Shishkin wrote:
> Currently, only one pmu in a context gets disabled during unthrottling
> and event_sched_{out,in}, however, events in one context may belong to
> different pmus, which results in pmus being reprogrammed while they are
> still enabled. This patch temporarily disables pmus that correspond to
> each event in the context while these events are being modified.
This is a generic bug fix and should be merged independent of the PT code.
This affects any setup using multiple PMUs at the same time.
Reviewed-by: Andi Kleen <a...@linux.intel.com>
-Andi
>
> Signed-off-by: Alexander Shishkin <alexander.shish...@linux.intel.com>
> ---
> kernel/events/core.c | 27 ++++++++++++++++++++++++---
> 1 file changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/events/core.c b/kernel/events/core.c
> index 403b781..d656cd6 100644
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -1396,6 +1396,9 @@ event_sched_out(struct perf_event *event,
> if (event->state != PERF_EVENT_STATE_ACTIVE)
> return;
>
> + if (event->pmu != ctx->pmu)
> + perf_pmu_disable(event->pmu);
> +
> event->state = PERF_EVENT_STATE_INACTIVE;
> if (event->pending_disable) {
> event->pending_disable = 0;
> @@ -1412,6 +1415,9 @@ event_sched_out(struct perf_event *event,
> ctx->nr_freq--;
> if (event->attr.exclusive || !cpuctx->active_oncpu)
> cpuctx->exclusive = 0;
> +
> + if (event->pmu != ctx->pmu)
> + perf_pmu_enable(event->pmu);
> }
>
> static void
> @@ -1652,6 +1658,7 @@ event_sched_in(struct perf_event *event,
> struct perf_event_context *ctx)
> {
> u64 tstamp = perf_event_time(event);
> + int ret = 0;
>
> if (event->state <= PERF_EVENT_STATE_OFF)
> return 0;
> @@ -1674,10 +1681,14 @@ event_sched_in(struct perf_event *event,
> */
> smp_wmb();
>
> + if (event->pmu != ctx->pmu)
> + perf_pmu_disable(event->pmu);
> +
> if (event->pmu->add(event, PERF_EF_START)) {
> event->state = PERF_EVENT_STATE_INACTIVE;
> event->oncpu = -1;
> - return -EAGAIN;
> + ret = -EAGAIN;
> + goto out;
> }
>
> event->tstamp_running += tstamp - event->tstamp_stopped;
> @@ -1693,7 +1704,11 @@ event_sched_in(struct perf_event *event,
> if (event->attr.exclusive)
> cpuctx->exclusive = 1;
>
> - return 0;
> +out:
> + if (event->pmu != ctx->pmu)
> + perf_pmu_enable(event->pmu);
> +
> + return ret;
> }
>
> static int
> @@ -2743,6 +2758,9 @@ static void perf_adjust_freq_unthr_context(struct
> perf_event_context *ctx,
> if (!event_filter_match(event))
> continue;
>
> + if (ctx->pmu != event->pmu)
> + perf_pmu_disable(event->pmu);
> +
> hwc = &event->hw;
>
> if (hwc->interrupts == MAX_INTERRUPTS) {
> @@ -2752,7 +2770,7 @@ static void perf_adjust_freq_unthr_context(struct
> perf_event_context *ctx,
> }
>
> if (!event->attr.freq || !event->attr.sample_freq)
> - continue;
> + goto next;
>
> /*
> * stop the event and update event->count
> @@ -2774,6 +2792,9 @@ static void perf_adjust_freq_unthr_context(struct
> perf_event_context *ctx,
> perf_adjust_period(event, period, delta, false);
>
> event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
> + next:
> + if (ctx->pmu != event->pmu)
> + perf_pmu_enable(event->pmu);
> }
>
> perf_pmu_enable(ctx->pmu);
> --
> 1.8.5.1
>
--
a...@linux.intel.com -- Speaking for myself only
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