Commit 6409c4da authored by Ingo Molnar's avatar Ingo Molnar
Browse files

sched: sched_clock() improvement: use in_nmi() 



make sure we dont execute more complex sched_clock() code in NMI context.

Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent af39241b

kernel/sched_clock.c

+8 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <linux/spinlock.h>

#include <linux/ktime.h>

#include <linux/module.h>

#include <linux/hardirq.h>



/*

 * Scheduler clock - returns current time in nanosec units.
@@ -151,6 +152,13 @@ u64 sched_clock_cpu(int cpu) 
	struct sched_clock_data *scd = cpu_sdc(cpu);

	u64 now, clock, this_clock, remote_clock;



	/*

	 * Normally this is not called in NMI context - but if it is,

	 * trying to do any locking here is totally lethal.

	 */

	if (unlikely(in_nmi()))

		return scd->clock;



	if (unlikely(!sched_clock_running))

		return 0ull;