[tip:perf/core] perf evlist: Use atomic.h for the perf_mmap refcount

From: tip-bot for Arnaldo Carvalho de Melo
Date: Wed May 20 2015 - 08:22:34 EST


Commit-ID: 7143849a5d6a5c623d81790d92f0033507c5b14f
Gitweb: http://git.kernel.org/tip/7143849a5d6a5c623d81790d92f0033507c5b14f
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Fri, 15 May 2015 15:45:16 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 15 May 2015 15:45:16 -0300

perf evlist: Use atomic.h for the perf_mmap refcount

Now that we have atomic.h, we should convert all of the existing
refcounts to use it.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-qhpv2etncj3hfofgj1aitkyv@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/evlist.c | 12 ++++++------
tools/perf/util/evlist.h | 3 ++-
2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 7ec1bf9..dc1dc2c 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -700,14 +700,14 @@ static bool perf_mmap__empty(struct perf_mmap *md)

static void perf_evlist__mmap_get(struct perf_evlist *evlist, int idx)
{
- ++evlist->mmap[idx].refcnt;
+ atomic_inc(&evlist->mmap[idx].refcnt);
}

static void perf_evlist__mmap_put(struct perf_evlist *evlist, int idx)
{
- BUG_ON(evlist->mmap[idx].refcnt == 0);
+ BUG_ON(atomic_read(&evlist->mmap[idx].refcnt) == 0);

- if (--evlist->mmap[idx].refcnt == 0)
+ if (atomic_dec_and_test(&evlist->mmap[idx].refcnt))
__perf_evlist__munmap(evlist, idx);
}

@@ -721,7 +721,7 @@ void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx)
perf_mmap__write_tail(md, old);
}

- if (md->refcnt == 1 && perf_mmap__empty(md))
+ if (atomic_read(&md->refcnt) == 1 && perf_mmap__empty(md))
perf_evlist__mmap_put(evlist, idx);
}

@@ -758,7 +758,7 @@ static void __perf_evlist__munmap(struct perf_evlist *evlist, int idx)
if (evlist->mmap[idx].base != NULL) {
munmap(evlist->mmap[idx].base, evlist->mmap_len);
evlist->mmap[idx].base = NULL;
- evlist->mmap[idx].refcnt = 0;
+ atomic_set(&evlist->mmap[idx].refcnt, 0);
}
auxtrace_mmap__munmap(&evlist->mmap[idx].auxtrace_mmap);
}
@@ -807,7 +807,7 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
* evlist layer can't just drop it when filtering events in
* perf_evlist__filter_pollfd().
*/
- evlist->mmap[idx].refcnt = 2;
+ atomic_set(&evlist->mmap[idx].refcnt, 2);
evlist->mmap[idx].prev = 0;
evlist->mmap[idx].mask = mp->mask;
evlist->mmap[idx].base = mmap(NULL, evlist->mmap_len, mp->prot,
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index c07b1a9..670e7f2 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -1,6 +1,7 @@
#ifndef __PERF_EVLIST_H
#define __PERF_EVLIST_H 1

+#include <linux/atomic.h>
#include <linux/list.h>
#include <api/fd/array.h>
#include <stdio.h>
@@ -27,7 +28,7 @@ struct record_opts;
struct perf_mmap {
void *base;
int mask;
- int refcnt;
+ atomic_t refcnt;
u64 prev;
struct auxtrace_mmap auxtrace_mmap;
char event_copy[PERF_SAMPLE_MAX_SIZE] __attribute__((aligned(8)));
--
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