Messages in this thread Patch in this message | | | From | Jiri Olsa <> | Subject | [PATCH 1/2] perf: Fix EXIT event notification | Date | Mon, 6 May 2013 18:27:17 +0200 |
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The perf_event_task_ctx needs to be called with preemption disabled, since it's checking for currently scheduled cpu against event cpu.
We disable preemption for task related perf event context if there's one defined, leaving up to the chance which cpu it gets scheduled in.
Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> Cc: Borislav Petkov <bp@alien8.de> --- kernel/events/core.c | 26 ++++++++++++++------------ 1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 6b41c18..38b68a0 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4474,7 +4474,7 @@ static void perf_event_task_ctx(struct perf_event_context *ctx, static void perf_event_task_event(struct perf_task_event *task_event) { struct perf_cpu_context *cpuctx; - struct perf_event_context *ctx; + struct perf_event_context *ctx, *task_ctx = task_event->task_ctx; struct pmu *pmu; int ctxn; @@ -4485,20 +4485,22 @@ static void perf_event_task_event(struct perf_task_event *task_event) goto next; perf_event_task_ctx(&cpuctx->ctx, task_event); - ctx = task_event->task_ctx; - if (!ctx) { - ctxn = pmu->task_ctx_nr; - if (ctxn < 0) - goto next; - ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); - if (ctx) - perf_event_task_ctx(ctx, task_event); - } + if (task_ctx) + goto next; + ctxn = pmu->task_ctx_nr; + if (ctxn < 0) + goto next; + ctx = rcu_dereference(current->perf_event_ctxp[ctxn]); + if (ctx) + perf_event_task_ctx(ctx, task_event); next: put_cpu_ptr(pmu->pmu_cpu_context); } - if (task_event->task_ctx) - perf_event_task_ctx(task_event->task_ctx, task_event); + if (task_ctx) { + preempt_disable(); + perf_event_task_ctx(task_ctx, task_event); + preempt_enable(); + } rcu_read_unlock(); } -- 1.7.11.7
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