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authorPekka Enberg <penberg@cs.helsinki.fi>2009-02-15 18:07:52 -0500
committerTheodore Ts'o <tytso@mit.edu>2009-02-15 18:07:52 -0500
commit705895b61133ef43d106fe6a6bbdb2eec923867e (patch)
treeea05232098c0425fda052240a8bb0e6218bb5e82 /fs/ext4/super.c
parent3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 (diff)
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.c10
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);