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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/ext4_sb.h | |
| parent | 3d0518f4758eca4339e75e5b9dbb7e06a5ce08b4 (diff) | |
| download | linux-705895b61133ef43d106fe6a6bbdb2eec923867e.tar.gz linux-705895b61133ef43d106fe6a6bbdb2eec923867e.tar.bz2 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.h | 4 |
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 */ |