From patchwork Wed Jan 12 10:39:50 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Ext4: use 'unlikely' to improve the efficiency of the kernel Date: Wed, 12 Jan 2011 00:39:50 -0000 From: Wang shilong X-Patchwork-Id: 211471 Message-Id: <1294828790-3455-1-git-send-email-wangshilong1991@gmail.com> To: tytso@mit.edu, adilger.kernel@dilger.ca Cc: linux-ext4@vger.kernel.org, Wang shilong , Wang Shilong From: Wang Shilong Since 'sb_getblk' seldomly return NULL,it will be better to use 'unlikely' to check it. Signed-off-by: Wang Shilong --- fs/ext4/resize.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index 7ea6cbb..2ef10e1 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))