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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>,
	Al Viro <viro@zeniv.linux.org.uk>, Christoph Hellwig <hch@lst.de>
Subject: [RFC][PATCH 09/10] fs: Remove unlikely() from fget_light()
Date: Mon, 06 Dec 2010 20:58:43 -0500	[thread overview]
Message-ID: <20101207021330.577045165@goodmis.org> (raw)
In-Reply-To: 20101207015834.196176991@goodmis.org

[-- Attachment #1: 0009-fs-Remove-unlikely-from-fget_light.patch --]
[-- Type: text/plain, Size: 1210 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

There's an unlikely() in fget_light() that assumes the file ref count
will be 1. Running the annotate branch profiler on a desktop that is
performing daily tasks (running firefox, evolution, xchat and is also part
of a distcc farm), it shows that the ref count is not 1 that often.

 correct incorrect      %    Function                  File              Line
 ------- ---------      -    --------                  ----              ----
1035099358 6209599193  85    fget_light              file_table.c         315

Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
 fs/file_table.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/fs/file_table.c b/fs/file_table.c
index c3dee38..c3e89ad 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -311,7 +311,7 @@ struct file *fget_light(unsigned int fd, int *fput_needed)
 	struct files_struct *files = current->files;
 
 	*fput_needed = 0;
-	if (likely((atomic_read(&files->count) == 1))) {
+	if (atomic_read(&files->count) == 1) {
 		file = fcheck_files(files, fd);
 	} else {
 		rcu_read_lock();
-- 
1.7.2.3



  parent reply	other threads:[~2010-12-07  2:13 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-07  1:58 [RFC][PATCH 00/10] incorrect unlikely() and likely() cleanups Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 01/10] sched: Change rt_task(prev) in pre_schedule_rt to likely Steven Rostedt
2010-12-07  3:25   ` Yong Zhang
2010-12-07  3:32     ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 02/10] mm: Remove likely() from mapping_unevictable() Steven Rostedt
2010-12-07  2:22   ` Steven Rostedt
2010-12-07  7:02     ` Nick Piggin
2010-12-07 13:06       ` Steven Rostedt
2010-12-07 16:26     ` Rik van Riel
2010-12-10  7:00     ` KOSAKI Motohiro
2010-12-10  7:06       ` Joe Perches
2010-12-10  8:08         ` Miles Bader
2010-12-11  0:09           ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 03/10] workqueue: It is likely that WORKER_NOT_RUNNING is true Steven Rostedt
2010-12-07  9:49   ` Tejun Heo
2010-12-07 13:07     ` Steven Rostedt
2010-12-11  0:08     ` Steven Rostedt
2010-12-11  0:09       ` Tejun Heo
2010-12-11  0:12         ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 04/10] sched: Change pick_next_task_rt from unlikely to likely Steven Rostedt
2010-12-07  2:46   ` Gregory Haskins
2010-12-07  2:59     ` Steven Rostedt
2010-12-11  0:07     ` Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 05/10] mm: Remove likely() from grab_cache_page_write_begin() Steven Rostedt
2010-12-07  2:24   ` Steven Rostedt
2010-12-07  6:56     ` Nick Piggin
2010-12-07  1:58 ` [RFC][PATCH 06/10] sched: Remove unlikely() from rt_policy() in sched.c Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 07/10] x86: Remove unlikey()s from sched_switch segment tests Steven Rostedt
2010-12-07  1:58 ` [RFC][PATCH 08/10] fs: Remove unlikely() from fput_light() Steven Rostedt
2010-12-07  1:58 ` Steven Rostedt [this message]
2010-12-07  1:58 ` [RFC][PATCH 10/10] sched: Remove unlikely() from ttwu_post_activation Steven Rostedt

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