2011-06-27 06:33:49

by Robin Dong

Subject: [PATCH] ext4: avoid redundant cache finding if flags not cantian PUNCH_OUT

In old code, ext4 will find extent in cache first even flags does
not contian PUNCH_OUT, that may waste some time.

Signed-off-by: Robin Dong <[email protected]>
---
fs/ext4/extents.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index eb63c7b..d583ec3 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -3358,8 +3358,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);

/* check in cache */
- if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
- ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
+ if (((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) &&
+ ext4_ext_in_cache(inode, map->m_lblk, &newex)) {
if (!newex.ee_start_lo && !newex.ee_start_hi) {
if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
/*
--
1.7.1

2011-06-27 10:15:09

by Lukas Czerner

Subject: Re: [PATCH] ext4: avoid redundant cache finding if flags not cantian PUNCH_OUT

On Mon, 27 Jun 2011, Robin Dong wrote:

> In old code, ext4 will find extent in cache first even flags does
> not contian PUNCH_OUT, that may waste some time.
>
> Signed-off-by: Robin Dong <[email protected]>
> ---
> fs/ext4/extents.c | 4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index eb63c7b..d583ec3 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3358,8 +3358,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
> trace_ext4_ext_map_blocks_enter(inode, map->m_lblk, map->m_len, flags);
>
> /* check in cache */
> - if (ext4_ext_in_cache(inode, map->m_lblk, &newex) &&
> - ((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0)) {
> + if (((flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) == 0) &&
> + ext4_ext_in_cache(inode, map->m_lblk, &newex)) {

Hi Robin,

The patch is good thanks, but I think that this:

if (!(flags & EXT4_GET_BLOCKS_PUNCH_OUT_EXT) &&
ext4_ext_in_cache(inode, map->m_lblk, &newex)) {

looks better.

Thanks!
-Lukas

> if (!newex.ee_start_lo && !newex.ee_start_hi) {
> if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) {
> /*
>