From 705895b61133ef43d106fe6a6bbdb2eec923867e Mon Sep 17 00:00:00 2001 From: Pekka Enberg Date: Sun, 15 Feb 2009 18:07:52 -0500 Subject: 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 Signed-off-by: Pekka Enberg Cc: Signed-off-by: Andrew Morton Signed-off-by: "Theodore Ts'o" --- fs/ext4/ext4_sb.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/ext4/ext4_sb.h') 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 */ -- cgit v1.2.3