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>

2 files changed, 13 insertions, 12 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index d89e2f106a62..109f3b269ac5 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -80,17 +80,6 @@ static const char		*cpu_list;
 
 static struct perf_mmap         mmap_array[MAX_NR_CPUS];
 
-static void 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;
-}
-
 static void advance_output(size_t size)
 {
         bytes_written += size;
@@ -165,7 +154,7 @@ static void mmap_read(struct perf_mmap *md)
         write_output(buf, size);
 
         md->prev = old;
-        mmap_write_tail(md, old);
+        perf_mmap__write_tail(md, old);
 }
 
 static volatile int done = 0;
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.