Commit-ID: 195564390210977954fe4ef45b39cdee34f41b59
Gitweb: http://git.kernel.org/tip/195564390210977954fe4ef45b39cdee34f41b59
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Mon, 30 Mar 2009 19:07:04 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 6 Apr 2009 09:30:37 +0200
perf_counter: kerneltop: simplify data_head read
Now that the kernel side changed, match up again.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Acked-by: Paul Mackerras <paulus@xxxxxxxxx>
Orig-LKML-Reference: <20090330171023.327144324@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
Documentation/perf_counter/kerneltop.c | 14 +-------------
1 files changed, 1 insertions(+), 13 deletions(-)
diff --git a/Documentation/perf_counter/kerneltop.c b/Documentation/perf_counter/kerneltop.c
index fda1438..2779c57 100644
--- a/Documentation/perf_counter/kerneltop.c
+++ b/Documentation/perf_counter/kerneltop.c
@@ -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;
}
--
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