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From: Theodore Ts'o <tytso@mit.edu>
To: linux-kernel@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>
Subject: [PATCH 1/5] fs: i_flags and i_state in struct inode only need to be unsigned short
Date: Thu, 21 May 2009 16:00:59 -0400	[thread overview]
Message-ID: <1242936063-31689-2-git-send-email-tytso@mit.edu> (raw)
In-Reply-To: <1242936063-31689-1-git-send-email-tytso@mit.edu>

Currently i_flags and i_state do not need to be an unsigned int and an
unsigned long, respectively.  (We currently use 9 i_flags bits, and 8
i_state bits.)  Changing them to be an unsigned short saves 4 bytes
per inode on an x86 platform, and 8 bytes on an x86_64 platform.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: linux-fsdevel@vger.kernel.org
---
 include/linux/fs.h |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 3b534e5..9b20f13 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -765,10 +765,10 @@ struct inode {
 	struct mutex		inotify_mutex;	/* protects the watches list */
 #endif
 
-	unsigned long		i_state;
 	unsigned long		dirtied_when;	/* jiffies of first dirtying */
 
-	unsigned int		i_flags;
+	unsigned short		i_state;
+	unsigned short		i_flags;
 
 	atomic_t		i_writecount;
 #ifdef CONFIG_SECURITY
-- 
1.6.3.1.1.g75fc.dirty


  reply	other threads:[~2009-05-21 20:01 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-21 20:00 [RFC PATCH 0/5] Put struct inode on a diet Theodore Ts'o
2009-05-21 20:00 ` Theodore Ts'o [this message]
2009-05-21 20:01   ` [PATCH 2/5] fs: Remove i_cindex from struct inode Theodore Ts'o
2009-05-21 20:01     ` [PATCH 3/5] fs: Slim down inode by only using an unsigned int for i_dnotify_mask Theodore Ts'o
2009-05-21 20:01       ` [PATCH 4/5] fs: Rearrange inode structure elements to avoid waste due to padding Theodore Ts'o
2009-05-21 20:01         ` [PATCH 5/5] Dump the inode structure (for debugging purposes only) Theodore Ts'o
2009-05-21 20:09           ` Matthew Wilcox
2009-05-21 20:28             ` Theodore Tso
2009-05-21 20:30     ` [PATCH 2/5] fs: Remove i_cindex from struct inode Stefan Richter

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