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ext4: use unlikely to improve the efficiency of the kernel

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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@cn.fujitsu.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Wang Shilong 2013-01-12 16:28:47 -05:00 committed by Theodore Ts'o
parent 860d21e2c5
commit aebf02430d
5 changed files with 13 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/ext4/extents.c
View File

@ -956,7 +956,7 @@ 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 = -ENOMEM;
goto cleanup;
}
@ -1029,7 +1029,7 @@ 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 = -ENOMEM;
goto cleanup;
}
@ -1142,7 +1142,7 @@ 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))
return -ENOMEM;
lock_buffer(bh);

6
fs/ext4/inode.c
View File

@ -713,7 +713,7 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
return NULL;
bh = sb_getblk(inode->i_sb, map.m_pblk);
if (!bh) {
if (unlikely(!bh)) {
*errp = -ENOMEM;
return NULL;
}
@ -3660,7 +3660,7 @@ 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))
return -ENOMEM;
if (!buffer_uptodate(bh)) {
lock_buffer(bh);
@ -3693,7 +3693,7 @@ 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;
/*

2
fs/ext4/mmp.c
View File

@ -93,7 +93,7 @@ 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;

10
fs/ext4/resize.c
View File

@ -333,7 +333,7 @@ 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(-ENOMEM);
if ((err = ext4_journal_get_write_access(handle, bh))) {
brelse(bh);
@ -410,7 +410,7 @@ 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 -ENOMEM;
err = ext4_journal_get_write_access(handle, bh);
@ -500,7 +500,7 @@ static int setup_new_flex_group_blocks(struct super_block *sb,
goto out;
gdb = sb_getblk(sb, block);
if (!gdb) {
if (unlikely(!gdb)) {
err = -ENOMEM;
goto out;
}
@ -1064,7 +1064,7 @@ static void update_backups(struct super_block *sb, int blk_off, char *data,
ext4_bg_has_super(sb, group));
bh = sb_getblk(sb, backup_block);
if (!bh) {
if (unlikely(!bh)) {
err = -ENOMEM;
break;
}
@ -1168,7 +1168,7 @@ 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 (!bh_uptodate_or_lock(bh)) {
if (bh_submit_read(bh) < 0) {

2
fs/ext4/xattr.c
View File

@ -886,7 +886,7 @@ inserted:
(unsigned long long)block);
new_bh = sb_getblk(sb, block);
if (!new_bh) {
if (unlikely(!new_bh)) {
error = -ENOMEM;
getblk_failed:
ext4_free_blocks(handle, inode, NULL, block, 1,