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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 /include/linux/ext2_fs_sb.h | |
| parent | 22d613d13445de9dea6edc3289c304237eb191f6 (diff) | |
| download | linux-18a82eb9f980b5e02cea651e4ecda26265d98933.tar.gz linux-18a82eb9f980b5e02cea651e4ecda26265d98933.tar.bz2 linux-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 'include/linux/ext2_fs_sb.h')
| -rw-r--r-- | include/linux/ext2_fs_sb.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/ext2_fs_sb.h b/include/linux/ext2_fs_sb.h index dc541f3653d1..1cdb66367c98 100644 --- a/include/linux/ext2_fs_sb.h +++ b/include/linux/ext2_fs_sb.h @@ -101,7 +101,7 @@ struct ext2_sb_info { struct percpu_counter s_freeblocks_counter; struct percpu_counter s_freeinodes_counter; struct percpu_counter s_dirs_counter; - struct blockgroup_lock s_blockgroup_lock; + struct blockgroup_lock *s_blockgroup_lock; /* root of the per fs reservation window tree */ spinlock_t s_rsv_window_lock; struct rb_root s_rsv_window_root; @@ -111,7 +111,7 @@ struct ext2_sb_info { static inline spinlock_t * sb_bgl_lock(struct ext2_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 /* _LINUX_EXT2_FS_SB */ |