Messages in this thread Patch in this message | | | Date | Thu, 20 Apr 2017 04:30:06 -0700 | From | "tip-bot for Peter Zijlstra (Intel)" <> | Subject | [tip:smp/hotplug] perf: Avoid cpu_hotplug_lock r-r recursion |
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Commit-ID: 641693094ee1568502280f95900f374b2226b51d Gitweb: http://git.kernel.org/tip/641693094ee1568502280f95900f374b2226b51d Author: Peter Zijlstra (Intel) <peterz@infradead.org> AuthorDate: Tue, 18 Apr 2017 19:05:05 +0200 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Thu, 20 Apr 2017 13:08:57 +0200
perf: Avoid cpu_hotplug_lock r-r recursion
There are two call-sites where using static_key results in recursing on the cpu_hotplug_lock.
Use the hotplug locked version of static_key_slow_inc().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Sebastian Siewior <bigeasy@linutronix.de> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: jbaron@akamai.com Link: http://lkml.kernel.org/r/20170418103422.687248115@infradead.org
--- kernel/events/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 634dd95..8aa3063 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7653,7 +7653,7 @@ static int perf_swevent_init(struct perf_event *event) if (err) return err; - static_key_slow_inc(&perf_swevent_enabled[event_id]); + static_key_slow_inc_cpuslocked(&perf_swevent_enabled[event_id]); event->destroy = sw_perf_event_destroy; } @@ -9160,7 +9160,7 @@ static void account_event(struct perf_event *event) mutex_lock(&perf_sched_mutex); if (!atomic_read(&perf_sched_count)) { - static_branch_enable(&perf_sched_events); + static_key_slow_inc_cpuslocked(&perf_sched_events.key); /* * Guarantee that all CPUs observe they key change and * call the perf scheduling hooks before proceeding to
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