From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752791AbcLDIr1 (ORCPT ); Sun, 4 Dec 2016 03:47:27 -0500 Received: from mail-pg0-f47.google.com ([74.125.83.47]:33470 "EHLO mail-pg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752549AbcLDIr0 (ORCPT ); Sun, 4 Dec 2016 03:47:26 -0500 From: David Carrillo-Cisneros To: linux-kernel@vger.kernel.org Cc: "x86@kernel.org" , Ingo Molnar , Thomas Gleixner , Andi Kleen , Kan Liang , Peter Zijlstra , Vegard Nossum , Marcelo Tosatti , Nilay Vaish , Borislav Petkov , Vikas Shivappa , Ravi V Shankar , Fenghua Yu , Paul Turner , Stephane Eranian , David Carrillo-Cisneros Subject: [PATCH] perf/core: remove invalid warning from list_update_cgroup_event Date: Sun, 4 Dec 2016 00:46:17 -0800 Message-Id: <1480841177-27299-1-git-send-email-davidcc@google.com> X-Mailer: git-send-email 2.8.0.rc3.226.g39d4020 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The warning introduced in commit: 979bfef8607c ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") assumed that a cgroup switch always precedes list_del_event. This is not the case. Remove warning. Make sure that cpuctx->cgrp is NULL until a cgroup event is sched in or ctx->nr_cgroups == 0. Signed-off-by: David Carrillo-Cisneros --- kernel/events/core.c | 19 ++++++++----------- 1 file changed, 8 insertions(+), 11 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index 6ee1feb..02c8421 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -903,17 +903,14 @@ list_update_cgroup_event(struct perf_event *event, */ cpuctx = __get_cpu_context(ctx); - /* Only set/clear cpuctx->cgrp if current task uses event->cgrp. */ - if (perf_cgroup_from_task(current, ctx) != event->cgrp) { - /* - * We are removing the last cpu event in this context. - * If that event is not active in this cpu, cpuctx->cgrp - * should've been cleared by perf_cgroup_switch. - */ - WARN_ON_ONCE(!add && cpuctx->cgrp); - return; - } - cpuctx->cgrp = add ? event->cgrp : NULL; + /* + * cpuctx->cgrp is NULL until a cgroup event is sched in or + * ctx->nr_cgroup == 0 . + */ + if (add && perf_cgroup_from_task(current, ctx) == event->cgrp) + cpuctx->cgrp = event->cgrp; + else if (!add) + cpuctx->cgrp = NULL; } #else /* !CONFIG_CGROUP_PERF */ -- 2.8.0.rc3.226.g39d4020