From 8fc31ce8896fc3cea1d79688c8ff950ad4e73afe Mon Sep 17 00:00:00 2001 From: David Carrillo-Cisneros Date: Sun, 4 Dec 2016 00:46:17 -0800 Subject: [PATCH] perf/core: Remove invalid warning from list_update_cgroup_even()t The warning introduced in commit: 864c2357ca89 ("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 Signed-off-by: Peter Zijlstra (Intel) Cc: Alexander Shishkin Cc: Arnaldo Carvalho de Melo Cc: Borislav Petkov Cc: Fenghua Yu Cc: Jiri Olsa Cc: Kan Liang Cc: Linus Torvalds Cc: Marcelo Tosatti Cc: Nilay Vaish Cc: Paul Turner Cc: Peter Zijlstra Cc: Ravi V Shankar Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vegard Nossum Cc: Vikas Shivappa Cc: Vince Weaver Link: http://lkml.kernel.org/r/1480841177-27299-1-git-send-email-davidcc@google.com Signed-off-by: Ingo Molnar --- 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 6ee1febdf6ff..02c8421f8c01 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 */ -- 2.20.1