perf_counter: avoid recursion

Tracepoint events like lock_acquire and software counters like
pagefaults can recurse into the perf counter code again, avoid that.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090323172417.152096433@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index 56099e52970d..18dc17d0a61c 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -328,6 +328,13 @@ struct perf_cpu_context {
         int                             active_oncpu;
         int                             max_pertask;
         int                             exclusive;
+
+        /*
+         * Recursion avoidance:
+         *
+         * task, softirq, irq, nmi context
+         */
+        int                     recursion[4];
 };
 
 /*