Patchwork [2/2] Ext3: use unlikely to improve the efficiency of the kernel

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Submitter Wang shilong
Date Jan. 12, 2013, 9:36 a.m.
Message ID <CAP9B-Q=GiV8fBk5cqR+yySUGidaFy=XKyNvZW=kQAKpqYsat4w@mail.gmail.com>
Download mbox | patch
Permalink /patch/211484/
State Not Applicable
Headers show

Comments

Wang shilong - Jan. 12, 2013, 9:36 a.m.
From: Wang Shilong <wangsl-fnst@cn.fujitsu.com>

Because the function 'sb_getblk' seldomly fails to return
NULL value,it will be better to use unlikely to check it.

Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
---
 fs/ext3/inode.c  |    6 +++---
 fs/ext3/resize.c |    6 +++---
 fs/ext3/xattr.c  |    2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)
Jan Kara - Jan. 14, 2013, 2:22 p.m.
On Sat 12-01-13 01:36:17, shilong wang wrote:
> From: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
> 
> Because the function 'sb_getblk' seldomly fails to return
> NULL value,it will be better to use unlikely to check it.
  Thanks. I've merged the patch. Here also applies my comment about line
wrapping from the previous patch...

								Honza
> 
> Signed-off-by: Wang Shilong <wangsl-fnst@cn.fujitsu.com>
> ---
>  fs/ext3/inode.c  |    6 +++---
>  fs/ext3/resize.c |    6 +++---
>  fs/ext3/xattr.c  |    2 +-
>  3 files changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
> index 61bc8bd..7338a76 100644
> --- a/fs/ext3/inode.c
> +++ b/fs/ext3/inode.c
> @@ -1083,7 +1083,7 @@ struct buffer_head *ext3_getblk(handle_t
> *handle, struct inode *inode,
>  	if (!err && buffer_mapped(&dummy)) {
>  		struct buffer_head *bh;
>  		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
> -		if (!bh) {
> +		if (unlikely(!bh)) {
>  			*errp = -EIO;
>  			goto err;
>  		}
> @@ -2734,7 +2734,7 @@ static int __ext3_get_inode_loc(struct inode *inode,
>  		return -EIO;
> 
>  	bh = sb_getblk(inode->i_sb, block);
> -	if (!bh) {
> +	if (unlikely(!bh)) {
>  		ext3_error (inode->i_sb, "ext3_get_inode_loc",
>  				"unable to read inode block - "
>  				"inode=%lu, block="E3FSBLK,
> @@ -2788,7 +2788,7 @@ static int __ext3_get_inode_loc(struct inode *inode,
> 
>  			bitmap_bh = sb_getblk(inode->i_sb,
>  					le32_to_cpu(desc->bg_inode_bitmap));
> -			if (!bitmap_bh)
> +			if (unlikely(!bitmap_bh))
>  				goto make_io;
> 
>  			/*
> diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c
> index 0f814f3..704e8ce 100644
> --- a/fs/ext3/resize.c
> +++ b/fs/ext3/resize.c
> @@ -116,7 +116,7 @@ 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 = ext3_journal_get_write_access(handle, bh))) {
>  		brelse(bh);
> @@ -234,7 +234,7 @@ static int setup_new_group_blocks(struct super_block *sb,
>  			goto exit_bh;
> 
>  		gdb = sb_getblk(sb, block);
> -		if (!gdb) {
> +		if (unlikely(!gdb)) {
>  			err = -EIO;
>  			goto exit_bh;
>  		}
> @@ -722,7 +722,7 @@ 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;
>  		}
> diff --git a/fs/ext3/xattr.c b/fs/ext3/xattr.c
> index d22ebb7..9f57470 100644
> --- a/fs/ext3/xattr.c
> +++ b/fs/ext3/xattr.c
> @@ -813,7 +813,7 @@ inserted:
>  			ea_idebug(inode, "creating block %d", block);
> 
>  			new_bh = sb_getblk(sb, block);
> -			if (!new_bh) {
> +			if (unlikely(!new_bh)) {
>  getblk_failed:
>  				ext3_free_blocks(handle, inode, block, 1);
>  				error = -EIO;
> -- 
> 1.7.7.6

Patch

diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 61bc8bd..7338a76 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1083,7 +1083,7 @@  struct buffer_head *ext3_getblk(handle_t
*handle, struct inode *inode,
 	if (!err && buffer_mapped(&dummy)) {
 		struct buffer_head *bh;
 		bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
-		if (!bh) {
+		if (unlikely(!bh)) {
 			*errp = -EIO;
 			goto err;
 		}
@@ -2734,7 +2734,7 @@  static int __ext3_get_inode_loc(struct inode *inode,
 		return -EIO;

 	bh = sb_getblk(inode->i_sb, block);
-	if (!bh) {
+	if (unlikely(!bh)) {
 		ext3_error (inode->i_sb, "ext3_get_inode_loc",
 				"unable to read inode block - "
 				"inode=%lu, block="E3FSBLK,
@@ -2788,7 +2788,7 @@  static int __ext3_get_inode_loc(struct inode *inode,

 			bitmap_bh = sb_getblk(inode->i_sb,
 					le32_to_cpu(desc->bg_inode_bitmap));
-			if (!bitmap_bh)
+			if (unlikely(!bitmap_bh))
 				goto make_io;

 			/*
diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c
index 0f814f3..704e8ce 100644
--- a/fs/ext3/resize.c
+++ b/fs/ext3/resize.c
@@ -116,7 +116,7 @@  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 = ext3_journal_get_write_access(handle, bh))) {
 		brelse(bh);
@@ -234,7 +234,7 @@  static int setup_new_group_blocks(struct super_block *sb,
 			goto exit_bh;

 		gdb = sb_getblk(sb, block);
-		if (!gdb) {
+		if (unlikely(!gdb)) {
 			err = -EIO;
 			goto exit_bh;
 		}
@@ -722,7 +722,7 @@  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;
 		}
diff --git a/fs/ext3/xattr.c b/fs/ext3/xattr.c
index d22ebb7..9f57470 100644
--- a/fs/ext3/xattr.c
+++ b/fs/ext3/xattr.c
@@ -813,7 +813,7 @@  inserted:
 			ea_idebug(inode, "creating block %d", block);

 			new_bh = sb_getblk(sb, block);
-			if (!new_bh) {
+			if (unlikely(!new_bh)) {
 getblk_failed:
 				ext3_free_blocks(handle, inode, block, 1);
 				error = -EIO;