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Message-ID: <CAP9B-Qn1pnXaq2VaeMQvCct6AftGrxy+53zS9BDWLZAXNNaP2g@mail.gmail.com>
Date: Sat, 12 Jan 2013 01:57:13 -0800
From: shilong wang <wangshilong1991@...il.com>
To: tytso@....edu
Cc: linux-ext4@...r.kernel.org
Subject: [PATCH] Ext4: use unlikely to improve the efficiency of the kernel
From: Wang Shilong <wangsl-fnst@...fujitsu.com>
Because the function 'sb_getblk' seldomly fails to return NULL
value,it will be better to use 'unlikely' to optimize it.
Signed-off-by: Wang Shilong <wangsl-fnst@...fujitsu.com>
---
fs/ext4/extents.c | 6 +++---
fs/ext4/inode.c | 6 +++---
fs/ext4/mmp.c | 2 +-
fs/ext4/resize.c | 10 +++++-----
fs/ext4/xattr.c | 2 +-
5 files changed, 13 insertions(+), 13 deletions(-)
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index aabbb3f..8d5f818 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -942,7 +942,7 @@ static int ext4_ext_split(handle_t *handle, struct
inode *inode,
goto cleanup;
}
bh = sb_getblk(inode->i_sb, newblock);
- if (!bh) {
+ if (unlikely(!bh)) {
err = -EIO;
goto cleanup;
}
@@ -1015,7 +1015,7 @@ static int ext4_ext_split(handle_t *handle,
struct inode *inode,
oldblock = newblock;
newblock = ablocks[--a];
bh = sb_getblk(inode->i_sb, newblock);
- if (!bh) {
+ if (unlikely(!bh)) {
err = -EIO;
goto cleanup;
}
@@ -1128,7 +1128,7 @@ static int ext4_ext_grow_indepth(handle_t
*handle, struct inode *inode,
return err;
bh = sb_getblk(inode->i_sb, newblock);
- if (!bh) {
+ if (unlikely(!bh)) {
err = -EIO;
ext4_std_error(inode->i_sb, err);
return err;
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index dff171c..7c7cbf0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -739,7 +739,7 @@ struct buffer_head *ext4_getblk(handle_t *handle,
struct inode *inode,
*errp = 0;
bh = sb_getblk(inode->i_sb, map.m_pblk);
- if (!bh) {
+ if (unlikely(!bh)) {
*errp = -EIO;
return NULL;
}
@@ -3590,7 +3590,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb);
bh = sb_getblk(sb, block);
- if (!bh) {
+ if (unlikely(!bh)) {
EXT4_ERROR_INODE_BLOCK(inode, block,
"unable to read itable block");
return -EIO;
@@ -3626,7 +3626,7 @@ static int __ext4_get_inode_loc(struct inode *inode,
/* Is the inode bitmap in cache? */
bitmap_bh = sb_getblk(sb, ext4_inode_bitmap(sb, gdp));
- if (!bitmap_bh)
+ if (unlikely(!bitmap_bh))
goto make_io;
/*
diff --git a/fs/ext4/mmp.c b/fs/ext4/mmp.c
index fe7c63f..5ea3726 100644
--- a/fs/ext4/mmp.c
+++ b/fs/ext4/mmp.c
@@ -91,7 +91,7 @@ static int read_mmp_block(struct super_block *sb,
struct buffer_head **bh,
*bh = NULL;
}
}
- if (!*bh) {
+ if (unlikely(!*bh)) {
ext4_warning(sb, "Error while reading MMP block %llu",
mmp_block);
return -EIO;
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 41f6ef6..66be5b0 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -309,7 +309,7 @@ static struct buffer_head *bclean(handle_t
*handle, struct super_block *sb,
int err;
bh = sb_getblk(sb, blk);
- if (!bh)
+ if (unlikely(!bh))
return ERR_PTR(-EIO);
if ((err = ext4_journal_get_write_access(handle, bh))) {
brelse(bh);
@@ -386,7 +386,7 @@ static int set_flexbg_block_bitmap(struct
super_block *sb, handle_t *handle,
return err;
bh = sb_getblk(sb, flex_gd->groups[group].block_bitmap);
- if (!bh)
+ if (unlikely(!bh))
return -EIO;
err = ext4_journal_get_write_access(handle, bh);
@@ -461,7 +461,7 @@ static int setup_new_flex_group_blocks(struct
super_block *sb,
goto out;
gdb = sb_getblk(sb, block);
- if (!gdb) {
+ if (unlikely(!gdb)) {
err = -EIO;
goto out;
}
@@ -983,7 +983,7 @@ static void update_backups(struct super_block *sb,
break;
bh = sb_getblk(sb, group * bpg + blk_off);
- if (!bh) {
+ if (unlikely(!bh)) {
err = -EIO;
break;
}
@@ -1074,7 +1074,7 @@ static int ext4_add_new_descs(handle_t *handle,
struct super_block *sb,
static struct buffer_head *ext4_get_bitmap(struct super_block *sb, __u64 block)
{
struct buffer_head *bh = sb_getblk(sb, block);
- if (!bh)
+ if (unlikely(!bh))
return NULL;
if (bitmap_uptodate(bh))
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 2cdb98d..3b05198 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -897,7 +897,7 @@ inserted:
(unsigned long long)block);
new_bh = sb_getblk(sb, block);
- if (!new_bh) {
+ if (unlikely(!new_bh)) {
getblk_failed:
ext4_free_blocks(handle, inode, NULL, block, 1,
EXT4_FREE_BLOCKS_METADATA);
--
1.7.7.6
--
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