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| author | Pekka Enberg <penberg@cs.helsinki.fi> | 2009-01-07 18:07:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-01-08 08:31:00 -0800 |
| commit | 5df096d67ec2b6578518caed7d57317a4b807aa1 (patch) | |
| tree | 8e92d19c89dea347eed6fc018fc6e4388bf9ebdc /include | |
| parent | f420d4dc4272fd223986762df2ad06056ddebada (diff) | |
| download | lwn-5df096d67ec2b6578518caed7d57317a4b807aa1.tar.gz lwn-5df096d67ec2b6578518caed7d57317a4b807aa1.zip | |
ext3: allocate ->s_blockgroup_lock separately
As spotted by kmemtrace, struct ext3_sb_info is 17152 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 ext3_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')
| -rw-r--r-- | include/linux/ext3_fs_sb.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/include/linux/ext3_fs_sb.h b/include/linux/ext3_fs_sb.h index e024e38248ff..76fdc0f4b028 100644 --- a/include/linux/ext3_fs_sb.h +++ b/include/linux/ext3_fs_sb.h @@ -60,7 +60,7 @@ struct ext3_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; @@ -86,7 +86,7 @@ struct ext3_sb_info { static inline spinlock_t * sb_bgl_lock(struct ext3_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_EXT3_FS_SB */ |