The patch titled
EXT2: Remove superblock lock contention in ext2_statfs
has been added to the -mm tree. Its filename is
ext2-remove-superblock-lock-contention-in-ext2_statfs.patch
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: EXT2: Remove superblock lock contention in ext2_statfs
From: Dave Kleikamp <shaggy@xxxxxxxxxxxxxx>
Fix a performance degradation introduced in 2.6.17. (30% degradation running
dbench with 16 threads)
Patch 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. This patch reverses that part of the patch.
Signed-off-by: Dave Kleikamp <shaggy@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
fs/ext2/balloc.c | 3 ++-
fs/ext2/ialloc.c | 3 ++-
fs/ext2/super.c | 2 --
3 files changed, 4 insertions(+), 4 deletions(-)
diff -puN fs/ext2/balloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs fs/ext2/balloc.c
--- a/fs/ext2/balloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs
+++ a/fs/ext2/balloc.c
@@ -539,7 +539,6 @@ unsigned long ext2_count_free (struct bu
#endif /* EXT2FS_DEBUG */
-/* Superblock must be locked */
unsigned long ext2_count_free_blocks (struct super_block * sb)
{
struct ext2_group_desc * desc;
@@ -549,6 +548,7 @@ unsigned long ext2_count_free_blocks (st
unsigned long bitmap_count, x;
struct ext2_super_block *es;
+ lock_super(sb);
es = EXT2_SB(sb)->s_es;
desc_count = 0;
bitmap_count = 0;
@@ -572,6 +572,7 @@ unsigned long ext2_count_free_blocks (st
printk("ext2_count_free_blocks: stored = %lu, computed = %lu, %lu\n",
(long)le32_to_cpu(es->s_free_blocks_count),
desc_count, bitmap_count);
+ unlock_super(sb);
return bitmap_count;
#else
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
diff -puN fs/ext2/ialloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs fs/ext2/ialloc.c
--- a/fs/ext2/ialloc.c~ext2-remove-superblock-lock-contention-in-ext2_statfs
+++ a/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;
@@ -649,6 +648,7 @@ unsigned long ext2_count_free_inodes (st
unsigned long bitmap_count = 0;
struct buffer_head *bitmap_bh = NULL;
+ lock_super(sb);
es = EXT2_SB(sb)->s_es;
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
unsigned x;
@@ -671,6 +671,7 @@ unsigned long ext2_count_free_inodes (st
printk("ext2_count_free_inodes: stored = %lu, computed = %lu, %lu\n",
percpu_counter_read(&EXT2_SB(sb)->s_freeinodes_counter),
desc_count, bitmap_count);
+ unlock_super(sb);
return desc_count;
#else
for (i = 0; i < EXT2_SB(sb)->s_groups_count; i++) {
diff -puN fs/ext2/super.c~ext2-remove-superblock-lock-contention-in-ext2_statfs fs/ext2/super.c
--- a/fs/ext2/super.c~ext2-remove-superblock-lock-contention-in-ext2_statfs
+++ a/fs/ext2/super.c
@@ -1044,7 +1044,6 @@ static int ext2_statfs (struct dentry *
unsigned long overhead;
int i;
- lock_super(sb);
if (test_opt (sb, MINIX_DF))
overhead = 0;
else {
@@ -1085,7 +1084,6 @@ static int ext2_statfs (struct dentry *
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;
}
_
Patches currently in -mm which might be from shaggy@xxxxxxxxxxxxxx are
ext2-remove-superblock-lock-contention-in-ext2_statfs.patch
fs-removing-useless-casts.patch
fs-jfs-conversion-to-generic-boolean.patch
ext3-more-whitespace-cleanups.patch
ext3-fix-sparse-warnings.patch
-
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