[tip:perf/core] perf cgroup: Use atomic.h for refcounting

From: tip-bot for Arnaldo Carvalho de Melo
Date: Wed May 20 2015 - 08:22:54 EST


Commit-ID: f812d3045c2385ac16237e68b156859c4005526e
Gitweb: http://git.kernel.org/tip/f812d3045c2385ac16237e68b156859c4005526e
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Fri, 15 May 2015 16:12:20 -0300
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Fri, 15 May 2015 16:12:20 -0300

perf cgroup: Use atomic.h for refcounting

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-t3v2uma5digcj2tpkrs3m84u@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/cgroup.c | 10 +++-------
tools/perf/util/cgroup.h | 4 +++-
2 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index 88f7be3..32e12ec 100644
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -115,23 +115,19 @@ static int add_cgroup(struct perf_evlist *evlist, char *str)
goto found;
n++;
}
- if (cgrp->refcnt == 0)
+ if (atomic_read(&cgrp->refcnt) == 0)
free(cgrp);

return -1;
found:
- cgrp->refcnt++;
+ atomic_inc(&cgrp->refcnt);
counter->cgrp = cgrp;
return 0;
}

void close_cgroup(struct cgroup_sel *cgrp)
{
- if (!cgrp)
- return;
-
- /* XXX: not reentrant */
- if (--cgrp->refcnt == 0) {
+ if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) {
close(cgrp->fd);
zfree(&cgrp->name);
free(cgrp);
diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h
index 89acd6d..b4b8cb4 100644
--- a/tools/perf/util/cgroup.h
+++ b/tools/perf/util/cgroup.h
@@ -1,12 +1,14 @@
#ifndef __CGROUP_H__
#define __CGROUP_H__

+#include <linux/atomic.h>
+
struct option;

struct cgroup_sel {
char *name;
int fd;
- int refcnt;
+ atomic_t refcnt;
};


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