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authorSteven Rostedt <rostedt@goodmis.org>2008-11-12 00:01:27 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-12 05:23:36 -0500
commit47e74f2ba8fbf9fb1378e2524e6cfdc2fb37f160 (patch)
tree7d49bf91e5409c432b259c26fcadff0450dffe43
parentc1e7abbc7afc97367cd77c8f2895c2169a8f9c87 (diff)
ring-buffer: no preempt for sched_clock()
Impact: disable preemption when calling sched_clock() The ring_buffer_time_stamp still uses sched_clock as its counter. But it is a bug to call it with preemption enabled. This requirement should not be pushed to the ring_buffer_time_stamp callers, so the ring_buffer_time_stamp needs to disable preemption when calling sched_clock. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--kernel/trace/ring_buffer.c8
1 files changed, 7 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index b08ee9f00c8d..231db209fa82 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -51,8 +51,14 @@ void tracing_off(void)
51/* FIXME!!! */ 51/* FIXME!!! */
52u64 ring_buffer_time_stamp(int cpu) 52u64 ring_buffer_time_stamp(int cpu)
53{ 53{
54 u64 time;
55
56 preempt_disable_notrace();
54 /* shift to debug/test normalization and TIME_EXTENTS */ 57 /* shift to debug/test normalization and TIME_EXTENTS */
55 return sched_clock() << DEBUG_SHIFT; 58 time = sched_clock() << DEBUG_SHIFT;
59 preempt_enable_notrace();
60
61 return time;
56} 62}
57 63
58void ring_buffer_normalize_time_stamp(int cpu, u64 *ts) 64void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)