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authorTejun Heo <tj@kernel.org>2017-10-28 18:49:37 +0200
committerIngo Molnar <mingo@kernel.org>2017-10-30 11:58:51 +0100
commitbe96b316deff35e119760982c43af74e606fa143 (patch)
tree0751806ebea8af27293e0892843e06e21a5d97f0 /kernel/events
parentMerge tag 'perf-urgent-for-mingo-4.14-20171027' of git://git.kernel.org/pub/s... (diff)
downloadlinux-be96b316deff35e119760982c43af74e606fa143.tar.xz
linux-be96b316deff35e119760982c43af74e606fa143.zip
perf/cgroup: Fix perf cgroup hierarchy support
The following commit: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") made list_update_cgroup_event() skip setting cpuctx->cgrp if no cgroup event targets %current's cgroup. This breaks perf_event's hierarchical support because events which target one of the ancestors get ignored. Fix it by using cgroup_is_descendant() test instead of equality. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: David Carrillo-Cisneros <davidcc@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: kernel-team@fb.com Cc: stable@vger.kernel.org # v4.9+ Fixes: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups") Link: http://lkml.kernel.org/r/20171028164237.GA972780@devbig577.frc2.facebook.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/events')
-rw-r--r--kernel/events/core.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9d93db81fa36..10cdb9c26b5d 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -901,9 +901,11 @@ list_update_cgroup_event(struct perf_event *event,
cpuctx_entry = &cpuctx->cgrp_cpuctx_entry;
/* cpuctx->cgrp is NULL unless a cgroup event is active in this CPU .*/
if (add) {
+ struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
+
list_add(cpuctx_entry, this_cpu_ptr(&cgrp_cpuctx_list));
- if (perf_cgroup_from_task(current, ctx) == event->cgrp)
- cpuctx->cgrp = event->cgrp;
+ if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
+ cpuctx->cgrp = cgrp;
} else {
list_del(cpuctx_entry);
cpuctx->cgrp = NULL;