Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752545Ab2JBMBD (ORCPT ); Tue, 2 Oct 2012 08:01:03 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:62828 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751221Ab2JBMBB (ORCPT ); Tue, 2 Oct 2012 08:01:01 -0400 MIME-Version: 1.0 In-Reply-To: <1349178781.7780.29.camel@twins> References: <20121002114218.GA5891@krava.brq.redhat.com> <1349178781.7780.29.camel@twins> Date: Tue, 2 Oct 2012 14:01:00 +0200 Message-ID: Subject: Re: [PATCH] perf cgroups: Fix perf_cgroup_switch schedule in warning From: Stephane Eranian To: Peter Zijlstra Cc: Jiri Olsa , LKML , Frederic Weisbecker , Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo Content-Type: text/plain; charset=UTF-8 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2030 Lines: 55 On Tue, Oct 2, 2012 at 1:53 PM, Peter Zijlstra wrote: > > On Tue, 2012-10-02 at 13:42 +0200, Jiri Olsa wrote: > > +++ b/kernel/events/core.c > > @@ -394,7 +394,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode) > > } > > > > if (mode & PERF_CGROUP_SWIN) { > > - WARN_ON_ONCE(cpuctx->cgrp); > > + WARN_ON_ONCE(cpuctx->cgrp && !cpuctx->ctx.is_active); > > + Wait a minute, I thought we had fixed that problem which was caused by the AMD IBS pmu not having the task_ctx_nr set properly or something like that. We were wrongfully sharing the cpuctx between PMUs. > > > /* set cgrp before ctxsw in to > > * allow event_filter_match() to not > > * have to pass task around > > OK, like you mentioned this is the result of multiple PMU being able to > share a cpuctx, shouldn't we in that case avoid the second loop over the > cpuctx as a whole? > > Would something like the below do? IIRC I introduced that active_pmu for > exactly such reasons.. > > --- > kernel/events/core.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 7b9df35..e98f014 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -372,6 +372,8 @@ void perf_cgroup_switch(struct task_struct *task, int mode) > > list_for_each_entry_rcu(pmu, &pmus, entry) { > cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); > + if (cpuctx->active_pmu != pmu) > + continue; > > /* > * perf_cgroup_events says at least one > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/