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Commit 19556439 authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf_counter: kerneltop: simplify data_head read 



Now that the kernel side changed, match up again.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: default avatarPaul Mackerras <paulus@samba.org>
Orig-LKML-Reference: <20090330171023.327144324@chello.nl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 38ff667b

Documentation/perf_counter/kerneltop.c

+1 −13
Original line number Diff line number Diff line
@@ -1125,22 +1125,10 @@ struct mmap_data { 
static unsigned int mmap_read_head(struct mmap_data *md)

{

	struct perf_counter_mmap_page *pc = md->base;

	unsigned int seq, head;



repeat:

	rmb();

	seq = pc->lock;



	if (unlikely(seq & 1)) {

		cpu_relax();

		goto repeat;

	}

	int head;



	head = pc->data_head;



	rmb();

	if (pc->lock != seq)

		goto repeat;



	return head;

}