[tip:perf/pebs] perf, x86: Fix LBR enable/disable vs cpuc->enabled

tip-bot for Peter Zijlstra
2010-03-10T13:23:37Z

Commit-ID: 2df202bf7520eaffcbfb07e45dfa3cfb0aeee2c0
Gitweb: http://git.kernel.org/tip/2df202bf7520eaffcbfb07e45dfa3cfb0aeee2c0
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Sat, 6 Mar 2010 13:48:54 +0100
Committer: Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 10 Mar 2010 13:23:37 +0100

perf, x86: Fix LBR enable/disable vs cpuc->enabled

We should never call ->enable with the pmu enabled, and we _can_ have
->disable called with the pmu enabled.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
arch/x86/kernel/cpu/perf_event_intel_lbr.c | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index dcec765..0145f99 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -69,7 +69,7 @@ static void intel_pmu_lbr_enable(struct perf_event *event)
if (!x86_pmu.lbr_nr)
return;

- WARN_ON(cpuc->enabled);
+ WARN_ON_ONCE(cpuc->enabled);

/*
* Reset the LBR stack if this is the first LBR user or
@@ -93,9 +93,10 @@ static void intel_pmu_lbr_disable(struct perf_event *event)
return;

cpuc->lbr_users--;
-
BUG_ON(cpuc->lbr_users < 0);
- WARN_ON(cpuc->enabled);
+
+ if (cpuc->enabled && !cpuc->lbr_users)
+ __intel_pmu_lbr_disable();
}

static void intel_pmu_lbr_enable_all(void)