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authorPekka Enberg <penberg@cs.helsinki.fi>2009-02-16 00:07:52 +0100
committerTheodore Ts'o <tytso@mit.edu>2009-02-16 00:07:52 +0100
commit705895b61133ef43d106fe6a6bbdb2eec923867e (patch)
treeea05232098c0425fda052240a8bb0e6218bb5e82 /fs/ext4/ext4_sb.h
parentext4: New rec_len encoding for very large blocksizes (diff)
downloadlinux-705895b61133ef43d106fe6a6bbdb2eec923867e.tar.xz
linux-705895b61133ef43d106fe6a6bbdb2eec923867e.zip
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/ext4_sb.h')
-rw-r--r--fs/ext4/ext4_sb.h4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ext4/ext4_sb.h b/fs/ext4/ext4_sb.h
index e318f486cc24..4e4d9cc3f40d 100644
--- a/fs/ext4/ext4_sb.h
+++ b/fs/ext4/ext4_sb.h
@@ -62,7 +62,7 @@ struct ext4_sb_info {
struct percpu_counter s_freeinodes_counter;
struct percpu_counter s_dirs_counter;
struct percpu_counter s_dirtyblocks_counter;
- struct blockgroup_lock s_blockgroup_lock;
+ struct blockgroup_lock *s_blockgroup_lock;
struct proc_dir_entry *s_proc;
/* Journaling */
@@ -149,7 +149,7 @@ struct ext4_sb_info {
static inline spinlock_t *
sb_bgl_lock(struct ext4_sb_info *sbi, unsigned int block_group)
{
- return bgl_lock_ptr(&sbi->s_blockgroup_lock, block_group);
+ return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
}
#endif /* _EXT4_SB */