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Commit 833f7329 authored by Dave Kleikamp's avatar Dave Kleikamp Committed by Linus Torvalds
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[PATCH] EXT2: Remove superblock lock contention in ext2_statfs 



Fix a performance degradation introduced in 2.6.17.  (30% degradation
running dbench with 16 threads)

Commit 21730eed, which claims to make
EXT2_DEBUG work again, moves the taking of the kernel lock out of
debug-only code in ext2_count_free_inodes and ext2_count_free_blocks and
into ext2_statfs.

The same problem was fixed in ext3 by removing the lock completely (commit
5b116879)

Signed-off-by: default avatarDave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent ac7fb273

fs/ext2/balloc.c

+0 −1
Original line number Diff line number Diff line
@@ -539,7 +539,6 @@ unsigned long ext2_count_free (struct buffer_head * map, unsigned int numchars) 


#endif  /*  EXT2FS_DEBUG  */



/* Superblock must be locked */

unsigned long ext2_count_free_blocks (struct super_block * sb)

{

	struct ext2_group_desc * desc;

fs/ext2/ialloc.c

+0 −1
Original line number Diff line number Diff line
@@ -637,7 +637,6 @@ fail: 
	return ERR_PTR(err);

}



/* Superblock must be locked */

unsigned long ext2_count_free_inodes (struct super_block * sb)

{

	struct ext2_group_desc *desc;

fs/ext2/super.c

+0 −2
Original line number Diff line number Diff line
@@ -1083,7 +1083,6 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf) 
	unsigned long overhead;

	int i;



	lock_super(sb);

	if (test_opt (sb, MINIX_DF))

		overhead = 0;

	else {
@@ -1124,7 +1123,6 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf) 
	buf->f_files = le32_to_cpu(sbi->s_es->s_inodes_count);

	buf->f_ffree = ext2_count_free_inodes (sb);

	buf->f_namelen = EXT2_NAME_LEN;

	unlock_super(sb);

	return 0;

}