diff options
| author | Peter Zijlstra <peterz@infradead.org> | 2020-03-05 13:38:51 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-03-20 13:06:22 +0100 |
| commit | 90c91dfb86d0ff545bd329d3ddd72c147e2ae198 (patch) | |
| tree | 3dc7861dc6d78390198dddbc38847e35a914b098 | |
| parent | d8a738689794c42c3844284b99ddf165d10a724e (diff) | |
perf/core: Fix endless multiplex timer
Kan and Andi reported that we fail to kill rotation when the flexible
events go empty, but the context does not. XXX moar
Fixes: fd7d55172d1e ("perf/cgroups: Don't rotate events for cgroups unnecessarily")
Reported-by: Andi Kleen <ak@linux.intel.com>
Reported-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200305123851.GX2596@hirez.programming.kicks-ass.net
| -rw-r--r-- | kernel/events/core.c | 20 |
1 files changed, 14 insertions, 6 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index ccf8d4fc6374..b5a68d26f0b9 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2291,6 +2291,7 @@ __perf_remove_from_context(struct perf_event *event, if (!ctx->nr_events && ctx->is_active) { ctx->is_active = 0; + ctx->rotate_necessary = 0; if (ctx->task) { WARN_ON_ONCE(cpuctx->task_ctx != ctx); cpuctx->task_ctx = NULL; @@ -3188,12 +3189,6 @@ static void ctx_sched_out(struct perf_event_context *ctx, if (!ctx->nr_active || !(is_active & EVENT_ALL)) return; - /* - * If we had been multiplexing, no rotations are necessary, now no events - * are active. - */ - ctx->rotate_necessary = 0; - perf_pmu_disable(ctx->pmu); if (is_active & EVENT_PINNED) { list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list) @@ -3203,6 +3198,13 @@ static void ctx_sched_out(struct perf_event_context *ctx, if (is_active & EVENT_FLEXIBLE) { list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list) group_sched_out(event, cpuctx, ctx); + + /* + * Since we cleared EVENT_FLEXIBLE, also clear + * rotate_necessary, is will be reset by + * ctx_flexible_sched_in() when needed. + */ + ctx->rotate_necessary = 0; } perf_pmu_enable(ctx->pmu); } @@ -3985,6 +3987,12 @@ ctx_event_to_rotate(struct perf_event_context *ctx) typeof(*event), group_node); } + /* + * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in() + * finds there are unschedulable events, it will set it again. + */ + ctx->rotate_necessary = 0; + return event; } |