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| author | Pekka Enberg <penberg@cs.helsinki.fi> | 2009-02-15 18:07:52 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2009-02-15 18:07:52 -0500 |
| commit | 705895b61133ef43d106fe6a6bbdb2eec923867e (patch) | |
| tree | ea05232098c0425fda052240a8bb0e6218bb5e82 /fs/ext4/super.c | |
| parent | 3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 (diff) | |
| download | linux-705895b61133ef43d106fe6a6bbdb2eec923867e.tar.bz2 | |
ext4: allocate ->s_blockgroup_lock separately
As spotted by kmemtrace, struct ext4_sb_info is 17664 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 ext4_sb_info
enough to fit a 2 KB slab cache so now we allocate 16 KB + 2 KB instead of
32 KB saving 14 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: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/super.c')
| -rw-r--r-- | fs/ext4/super.c | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index f7371a6a923d..a3768709ce05 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -615,6 +615,7 @@ static void ext4_put_super(struct super_block *sb) ext4_blkdev_remove(sbi); } sb->s_fs_info = NULL; + kfree(sbi->s_blockgroup_lock); kfree(sbi); return; } @@ -2021,6 +2022,13 @@ static int ext4_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 = EXT4_DEF_RESUID; @@ -2332,7 +2340,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) &sbi->s_inode_readahead_blks); #endif - 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, logical_sb_block, i); |