From: Jiri Olsa <jolsa@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: Jiri Olsa <jolsa@kernel.org>, Adrian Hunter <adrian.hunter@intel.com>,
        Arnaldo Carvalho de Melo <acme@redhat.com>,
        Corey Ashford <cjashfor@linux.vnet.ibm.com>,
        David Ahern <dsahern@gmail.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, Milian Wolff <mail@milianw.de>,
        Namhyung Kim <namhyung@kernel.org>, Paul Mackerras <paulus@samba.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH 1/5] perf tools: Do not set O_NONBLOCK flag for perf event fd
Date: Wed,  1 Oct 2014 18:00:25 +0200
Message-Id: <1412179229-19466-1-git-send-email-jolsa@kernel.org>
Sender: linux-kernel-owner@vger.kernel.org

We don't need O_NONBLOCK flag on perf event file descriptors.

Aside the fact that file descriptors in evlist::pollfd are
never used in read syscall (write syscall is not supported),
the kernel perf read syscall path could never block anyway.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Milian Wolff <mail@milianw.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 tools/perf/util/evlist.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 3cebc9a8d52e..0fbc5f082308 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -434,12 +434,9 @@ static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx
 	 * Save the idx so that when we filter out fds POLLHUP'ed we can
 	 * close the associated evlist->mmap[] entry.
 	 */
-	if (pos >= 0) {
+	if (pos >= 0)
 		evlist->pollfd.priv[pos].idx = idx;
 
-		fcntl(fd, F_SETFL, O_NONBLOCK);
-	}
-
 	return pos;
 }
 
-- 
1.9.3

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