From 115d2d8963a426670ac3ce983fc4c4e001703943 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Wed, 12 Jan 2011 17:11:53 -0200
Subject: perf record: Move perf_mmap__write_tail to perf.h

Close to perf_mmap__read_head() and the perf_mmap struct definition.
This is useful for any recorder, and we will need it in 'perf test'.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/perf.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'tools/perf/perf.h')

diff --git a/tools/perf/perf.h b/tools/perf/perf.h
index 5fb5e1f11d1c..a5fc660c1f12 100644
--- a/tools/perf/perf.h
+++ b/tools/perf/perf.h
@@ -108,6 +108,18 @@ static inline unsigned int perf_mmap__read_head(struct perf_mmap *mm)
 	return head;
 }
 
+static inline void perf_mmap__write_tail(struct perf_mmap *md,
+					 unsigned long tail)
+{
+	struct perf_event_mmap_page *pc = md->base;
+
+	/*
+	 * ensure all reads are done before we write the tail out.
+	 */
+	/* mb(); */
+	pc->data_tail = tail;
+}
+
 /*
  * prctl(PR_TASK_PERF_EVENTS_DISABLE) will (cheaply) disable all
  * counters in the current task.
-- 
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