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authorPekka Enberg <penberg@cs.helsinki.fi>2009-01-07 18:07:25 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-08 08:31:00 -0800
commit5df096d67ec2b6578518caed7d57317a4b807aa1 (patch)
tree8e92d19c89dea347eed6fc018fc6e4388bf9ebdc /fs/ext3
parentf420d4dc4272fd223986762df2ad06056ddebada (diff)
downloadlinux-5df096d67ec2b6578518caed7d57317a4b807aa1.tar.gz
ext3: allocate ->s_blockgroup_lock separately
As spotted by kmemtrace, struct ext3_sb_info is 17152 bytes on 64-bit
which makes it a very bad fit for SLAB allocators.  The culprit of the
wasted memory is ->s_blockgroup_lock which can be as big as 16 KB when
NR_CPUS >= 32.

To fix that, allocate ->s_blockgroup_lock, which fits nicely in a order 2
page in the worst case, separately.  This shinks down struct ext3_sb_info
enough to fit a 1 KB slab cache so now we allocate 16 KB + 1 KB instead of
32 KB saving 15 KB of memory.

Acked-by: Andreas Dilger <adilger@sun.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext3')
-rw-r--r--fs/ext3/super.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
index c22d01467bd1..01c235bc2054 100644
--- a/fs/ext3/super.c
+++ b/fs/ext3/super.c
@@ -439,6 +439,7 @@ static void ext3_put_super (struct super_block * sb)
 		ext3_blkdev_remove(sbi);
 	}
 	sb->s_fs_info = NULL;
+	kfree(sbi->s_blockgroup_lock);
 	kfree(sbi);
 	return;
 }
@@ -1546,6 +1547,13 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 	sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
 	if (!sbi)
 		return -ENOMEM;
+
+	sbi->s_blockgroup_lock =
+		kzalloc(sizeof(struct blockgroup_lock), GFP_KERNEL);
+	if (!sbi->s_blockgroup_lock) {
+		kfree(sbi);
+		return -ENOMEM;
+	}
 	sb->s_fs_info = sbi;
 	sbi->s_mount_opt = 0;
 	sbi->s_resuid = EXT3_DEF_RESUID;
@@ -1786,7 +1794,7 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent)
 		goto failed_mount;
 	}
 
-	bgl_lock_init(&sbi->s_blockgroup_lock);
+	bgl_lock_init(sbi->s_blockgroup_lock);
 
 	for (i = 0; i < db_count; i++) {
 		block = descriptor_loc(sb, logic_sb_block, i);