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| author | Pekka J Enberg <penberg@cs.helsinki.fi> | 2009-01-07 18:07:19 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-08 08:31:00 -0800 |
| commit | 18a82eb9f980b5e02cea651e4ecda26265d98933 (patch) | |
| tree | 7626c16d880eed47f0eaf323f8e8e9441c84d357 /fs/ext2 | |
| parent | 22d613d13445de9dea6edc3289c304237eb191f6 (diff) | |
| download | lwn-18a82eb9f980b5e02cea651e4ecda26265d98933.tar.gz lwn-18a82eb9f980b5e02cea651e4ecda26265d98933.zip | |
ext2: allocate ->s_blockgroup_lock separately
As spotted by kmemtrace, struct ext2_sb_info is 17024 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 ext2_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/ext2')
| -rw-r--r-- | fs/ext2/super.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 647cd888ac87..da8bdeaa2e6d 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -132,6 +132,7 @@ static void ext2_put_super (struct super_block * sb) percpu_counter_destroy(&sbi->s_dirs_counter); brelse (sbi->s_sbh); sb->s_fs_info = NULL; + kfree(sbi->s_blockgroup_lock); kfree(sbi); return; @@ -756,6 +757,13 @@ static int ext2_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_sb_block = sb_block; @@ -983,7 +991,7 @@ static int ext2_fill_super(struct super_block *sb, void *data, int silent) printk ("EXT2-fs: not enough memory\n"); goto failed_mount; } - bgl_lock_init(&sbi->s_blockgroup_lock); + bgl_lock_init(sbi->s_blockgroup_lock); sbi->s_debts = kcalloc(sbi->s_groups_count, sizeof(*sbi->s_debts), GFP_KERNEL); if (!sbi->s_debts) { printk ("EXT2-fs: not enough memory\n"); |