From: Ravi Bangoria <ravi.bangoria@amd.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: acme@kernel.org, alexander.shishkin@linux.intel.com,
jolsa@redhat.com, namhyung@kernel.org, songliubraving@fb.com,
eranian@google.com, alexey.budankov@linux.intel.com,
ak@linux.intel.com, mark.rutland@arm.com, megha.dey@intel.com,
frederic@kernel.org, maddy@linux.ibm.com, irogers@google.com,
kim.phillips@amd.com, linux-kernel@vger.kernel.org,
santosh.shukla@amd.com, ravi.bangoria@amd.com
Subject: Re: [RFC v2] perf: Rewrite core context handling
Date: Mon, 22 Aug 2022 20:08:29 +0530 [thread overview]
Message-ID: <5f2efe0f-fb81-3bed-3aa4-a3b15d823946@amd.com> (raw)
In-Reply-To: <YqdMmLqFS9cX4jRb@hirez.programming.kicks-ass.net>
[...]
> You mentioned trouble with cpc->task_epc, there's one rebase mistake
> from you and an original bug from me.
>
> You lost the last hunk, I forgot to clear cpc on
> perf_remove_from_context().
>
> With these fixes I can run: 'perf test' without things going
> insta-splat.
>
> --- a/kernel/events/core.c
> +++ b/kernel/events/core.c
> @@ -2311,6 +2311,7 @@ __perf_remove_from_context(struct perf_e
> struct perf_event_context *ctx,
> void *info)
> {
> + struct perf_event_pmu_context *pmu_ctx = event->pmu_ctx;
> unsigned long flags = (unsigned long)info;
>
> if (ctx->is_active & EVENT_TIME) {
> @@ -2325,8 +2326,17 @@ __perf_remove_from_context(struct perf_e
> perf_child_detach(event);
> list_del_event(event, ctx);
>
> - if (!event->pmu_ctx->nr_events)
> - event->pmu_ctx->rotate_necessary = 0;
> + if (!pmu_ctx->nr_events) {
> + pmu_ctx->rotate_necessary = 0;
> +
> + if (ctx->task) {
IIUC, this should also check for ctx->is_active? i.e.
if (ctx->task && ctx->is_active) {
...
> + struct perf_cpu_pmu_context *cpc;
> +
> + cpc = this_cpu_ptr(pmu_ctx->pmu->cpu_pmu_context);
> + WARN_ON_ONCE(cpc->task_epc && cpc->task_epc != pmu_ctx);
> + cpc->task_epc = NULL;
> + }
> + }
Thanks,
Ravi
next prev parent reply other threads:[~2022-08-22 14:38 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-13 13:47 [RFC v2] perf: Rewrite core context handling Ravi Bangoria
2022-01-17 7:18 ` [perf] f7cf7134e4: WARNING:at_kernel/events/core.c:#__pmu_ctx_sched_out kernel test robot
2022-01-31 4:43 ` [RFC v2] perf: Rewrite core context handling Ravi Bangoria
2022-06-13 14:35 ` Peter Zijlstra
2022-06-13 14:36 ` Peter Zijlstra
2022-06-13 14:38 ` Peter Zijlstra
2022-08-02 6:11 ` Ravi Bangoria
2022-08-22 15:29 ` Peter Zijlstra
2022-08-22 15:43 ` Peter Zijlstra
2022-08-22 16:37 ` Ravi Bangoria
2022-08-23 4:20 ` Ravi Bangoria
2022-08-29 3:54 ` Ravi Bangoria
2022-08-23 6:30 ` Peter Zijlstra
2022-08-29 4:00 ` Ravi Bangoria
2022-08-29 11:58 ` Peter Zijlstra
2022-08-22 16:52 ` Peter Zijlstra
2022-08-23 4:57 ` Ravi Bangoria
2022-06-13 14:41 ` Peter Zijlstra
2022-08-22 14:38 ` Ravi Bangoria [this message]
2022-06-13 14:43 ` Peter Zijlstra
2022-08-02 6:16 ` Ravi Bangoria
2022-08-23 8:57 ` Peter Zijlstra
2022-08-24 5:07 ` Ravi Bangoria
2022-08-24 7:27 ` Peter Zijlstra
2022-08-24 7:53 ` Ravi Bangoria
2022-06-13 14:55 ` Peter Zijlstra
2022-08-02 6:10 ` Ravi Bangoria
2022-08-22 16:44 ` Peter Zijlstra
2022-08-23 4:46 ` Ravi Bangoria
2022-06-17 13:36 ` Peter Zijlstra
2022-08-24 10:13 ` Peter Zijlstra
2022-06-27 4:18 ` Ravi Bangoria
2022-08-02 6:06 ` Ravi Bangoria
2022-08-24 12:15 ` Peter Zijlstra
2022-08-24 14:59 ` Peter Zijlstra
2022-08-25 5:39 ` Ravi Bangoria
2022-08-25 9:17 ` Peter Zijlstra
2022-08-25 11:03 ` Ravi Bangoria
2022-08-02 6:13 ` Ravi Bangoria
2022-08-23 7:10 ` Peter Zijlstra
2022-08-02 6:17 ` Ravi Bangoria
2022-08-23 7:26 ` Peter Zijlstra
2022-08-23 15:14 ` Ravi Bangoria
2022-08-22 14:40 ` Ravi Bangoria
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