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authorDave Kleikamp <shaggy@austin.ibm.com>2006-09-18 20:12:33 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-09-19 07:59:59 -0700
commit833f73299fdf4497af1552e219e95661f4d2cdca (patch)
tree3a8cbf486dce86116ada64d170896141ceee4692 /fs
parentac7fb273ca1d0b4fb354575bb6e101ffd09e0b54 (diff)
downloadlinux-833f73299fdf4497af1552e219e95661f4d2cdca.tar.gz
[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 21730eed11de42f22afcbd43f450a1872a0b5ea1, 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
5b11687924e40790deb0d5f959247ade82196665)

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>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext2/balloc.c1
-rw-r--r--fs/ext2/ialloc.c1
-rw-r--r--fs/ext2/super.c2
3 files changed, 0 insertions, 4 deletions
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index d4870432ecfc..b1981d0e95ad 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -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;
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index de85c61c58c5..695f69ccf908 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -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;
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index ca5bfb6914d2..4286ff6330b6 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -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;
 }