Messages in this thread Patch in this message | | | Date | Thu, 13 Aug 2009 11:00:54 GMT | From | tip-bot for Peter Zijlstra <> | Subject | [tip:perfcounters/urgent] perf_counter: Fix an ipi-deadlock |
| |
Commit-ID: 970892a9031a5dc7217bd394fb9d89fa75a4a7bc Gitweb: http://git.kernel.org/tip/970892a9031a5dc7217bd394fb9d89fa75a4a7bc Author: Peter Zijlstra <a.p.zijlstra@chello.nl> AuthorDate: Thu, 13 Aug 2009 11:47:54 +0200 Committer: Ingo Molnar <mingo@elte.hu> CommitDate: Thu, 13 Aug 2009 12:58:05 +0200
perf_counter: Fix an ipi-deadlock
perf_pending_counter() is called from IRQ context and will call perf_counter_disable(), however perf_counter_disable() uses smp_call_function_single() which doesn't fancy being used with IRQs disabled due to IPI deadlocks.
Fix this by making it use the local __perf_counter_disable() call and teaching the counter_sched_out() code about pending disables as well.
This should cover the case where a counter migrates before the pending queue gets processed.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey J Ashford <cjashfor@us.ibm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: stephane eranian <eranian@googlemail.com> LKML-Reference: <20090813103655.244097721@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- kernel/perf_counter.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-)
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index b8c6b97..3f841be 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -307,6 +307,10 @@ counter_sched_out(struct perf_counter *counter, return; counter->state = PERF_COUNTER_STATE_INACTIVE; + if (counter->pending_disable) { + counter->pending_disable = 0; + counter->state = PERF_COUNTER_STATE_OFF; + } counter->tstamp_stopped = ctx->time; counter->pmu->disable(counter); counter->oncpu = -1; @@ -2343,7 +2347,7 @@ static void perf_pending_counter(struct perf_pending_entry *entry) if (counter->pending_disable) { counter->pending_disable = 0; - perf_counter_disable(counter); + __perf_counter_disable(counter); } if (counter->pending_wakeup) {
| |