[PATCH] EXT2: Remove superblock lock contention in ext2_statfs (833f7329) · Commits · 戴 / test

Fix a performance degradation introduced in 2.6.17. (30% degradation running dbench with 16 threads) Commit , 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 ) Signed-off-by:

Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by:

Andrew Morton <akpm@osdl.org> Signed-off-by:

Linus Torvalds <torvalds@osdl.org>

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;
		}

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