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authorPekka Enberg <penberg@cs.helsinki.fi>2009-01-07 21:07:25 -0500
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-08 11:31:00 -0500
commit5df096d67ec2b6578518caed7d57317a4b807aa1 (patch)
tree8e92d19c89dea347eed6fc018fc6e4388bf9ebdc /include/linux/ext3_fs_sb.h
parentf420d4dc4272fd223986762df2ad06056ddebada (diff)
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/linux/ext3_fs_sb.h')
-rw-r--r--include/linux/ext3_fs_sb.h4
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 {
60 struct percpu_counter s_freeblocks_counter; 60 struct percpu_counter s_freeblocks_counter;
61 struct percpu_counter s_freeinodes_counter; 61 struct percpu_counter s_freeinodes_counter;
62 struct percpu_counter s_dirs_counter; 62 struct percpu_counter s_dirs_counter;
63 struct blockgroup_lock s_blockgroup_lock; 63 struct blockgroup_lock *s_blockgroup_lock;
64 64
65 /* root of the per fs reservation window tree */ 65 /* root of the per fs reservation window tree */
66 spinlock_t s_rsv_window_lock; 66 spinlock_t s_rsv_window_lock;
@@ -86,7 +86,7 @@ struct ext3_sb_info {
86static inline spinlock_t * 86static inline spinlock_t *
87sb_bgl_lock(struct ext3_sb_info *sbi, unsigned int block_group) 87sb_bgl_lock(struct ext3_sb_info *sbi, unsigned int block_group)
88{ 88{
89 return bgl_lock_ptr(&sbi->s_blockgroup_lock, block_group); 89 return bgl_lock_ptr(sbi->s_blockgroup_lock, block_group);
90} 90}
91 91
92#endif /* _LINUX_EXT3_FS_SB */ 92#endif /* _LINUX_EXT3_FS_SB */