Commit-ID: be96b316deff35e119760982c43af74e606fa143
Gitweb: https://git.kernel.org/tip/be96b316deff35e119760982c43af74e606fa143
Author: Tejun Heo <tj@xxxxxxxxxx>
AuthorDate: Sat, 28 Oct 2017 09:49:37 -0700
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 30 Oct 2017 11:58:51 +0100
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@xxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: David Carrillo-Cisneros <davidcc@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: kernel-team@xxxxxx
Cc: stable@xxxxxxxxxxxxxxx # v4.9+
Fixes: 864c2357ca89 ("perf/core: Do not set cpuctx->cgrp for unscheduled cgroups")
Link: http://lkml.kernel.org/r/20171028164237.GA972780@xxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/events/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 9d93db8..10cdb9c 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;
--
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