Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.13 34/36] perf/cgroup: Fix perf cgroup hierarchy support | Date | Mon, 6 Nov 2017 10:12:47 +0100 |
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4.13-stable review patch. If anyone has any objections, please let me know.
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From: Tejun Heo <tj@kernel.org>
commit be96b316deff35e119760982c43af74e606fa143 upstream.
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 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- kernel/events/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -901,9 +901,11 @@ list_update_cgroup_event(struct perf_eve 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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