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tracing/ftrace: use preempt_enable_no_resched_notrace in ring_buffer_time_stamp() 

Impact: prevent a trace recursion

After some tests with function graph tracer under x86-32, I saw some recursions
caused by ring_buffer_time_stamp() that calls preempt_enable_no_notrace() which
calls preempt_schedule() which is traced itself.

This patch re-enables preemption without rescheduling.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker 2008-12-16 22:08:58 +01:00 committed by Ingo Molnar
parent 9dfc3bc7d2
commit 2c2d7329d8
1 changed files with 1 additions and 1 deletions
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kernel/trace/ring_buffer.c
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@ -107,7 +107,7 @@ u64 ring_buffer_time_stamp(int cpu)
preempt_disable_notrace();
/* shift to debug/test normalization and TIME_EXTENTS */
time = sched_clock() << DEBUG_SHIFT;
preempt_enable_notrace();
preempt_enable_no_resched_notrace();
return time;
}