2011/7/12 Ted Ts'o <tytso@xxxxxxx>:
> On Thu, Jun 30, 2011 at 04:42:31PM +0800, Yongqiang Yang wrote:
>> How about:
>> next = EXT_MAX_BLOCKS;
>> if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
>> next = ext4_ext_next_leaf_block(inode, path);
>> if (next != EXT_MAX_BLOCKS) {
>
> Agreed, that's a better way of doing things. Also, Robin, please
> compare and contrast your description with mine. The commit
> description shouldn't just be a textual description of the change. It
> should give the larger context of the change and why it's important.
>
> - Ted
>
> commit 2a3f7e0e0e55f8817fbe92d111ef2a06e6b8ef18
> Author: Robin Dong <sanbai@xxxxxxxxxx>
> Date: Mon Jul 11 15:43:38 2011 -0400
>
> ext4: avoid unneeded ext4_ext_next_leaf_block() while inserting extents
>
> Optimize ext4_exT_insert_extent() by avoiding
> ext4_ext_next_leaf_block() when the result is not used/needed.
>
> Signed-off-by: Robin Dong <sanbai@xxxxxxxxxx>
> Signed-off-by: "Theodore Ts'o" <tytso@xxxxxxx>
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 9cbdcb2..f1c538e 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -1730,9 +1730,10 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
>
> /* probably next leaf has space for us? */
> fex = EXT_LAST_EXTENT(eh);
> - next = ext4_ext_next_leaf_block(inode, path);
> - if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block)
> - && next != EXT_MAX_BLOCKS) {
> + next = EXT_MAX_BLOCKS;
> + if (le32_to_cpu(newext->ee_block) > le32_to_cpu(fex->ee_block))
> + next = ext4_ext_next_leaf_block(inode, path);
> + if (next != EXT_MAX_BLOCKS) {
> ext_debug("next leaf block - %d\n", next);
> BUG_ON(npath != NULL);
> npath = ext4_ext_find_extent(inode, next, NULL);
>
It seems much better than my description. Thanks!
--
--
Best Regard
Robin Dong
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