Message ID | 1309171513-5246-1-git-send-email-sanbai@taobao.com |
---|---|
State | Superseded, archived |
Headers | show |
Hi Robin Dong Why don't modify this line? if ((flags & EXT4_GET_BLOCKS_CREATE) == 0) { if(!(flags & EXT4_GET_BLOCKS_CREATE)) 2011/6/27 Robin Dong <hao.bigrat@gmail.com>: > 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 <sanbai@taobao.com> > Reviewed-by: Lukas Czerner <lczerner@redhat.com> > --- > 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..fed2633 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) && > + 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Best Regards -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jun 27, 2011 at 06:45:13PM +0800, Robin Dong wrote: > Subject: [PATCH v2] ext4: avoid redundant cache finding if flags not cantian I suspect you mean "contain" as opposed to "cantian". > In old code, ext4 will find extent in cache first even flags does > not contian PUNCH_OUT, that may waste some time. Same here ("contian"). --D > > Signed-off-by: Robin Dong <sanbai@taobao.com> > Reviewed-by: Lukas Czerner <lczerner@redhat.com> > --- > 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..fed2633 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) && > + 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 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Jun 27, 2011 at 12:59, Darrick J. Wong <djwong@us.ibm.com> wrote: > On Mon, Jun 27, 2011 at 06:45:13PM +0800, Robin Dong wrote: >> Subject: [PATCH v2] ext4: avoid redundant cache finding if flags not cantian > > I suspect you mean "contain" as opposed to "cantian". The patch summary line could also use some shortening. >> In old code, ext4 will find extent in cache first even flags does >> not contian PUNCH_OUT, that may waste some time. > > Same here ("contian"). How about something along the lines of: --------- ext4: avoid wasted extent cache lookup if !PUNCH_OUT_EXT This patch avoids an extraneous lookup of the extent cache in ext4_ext_map_blocks() when the flag EXT4_GET_BLOCKS_PUNCH_OUT_EXT is absent. The existing logic was performing the lookup but not making use of the result. The patch simply reverses the order of evaluation in the condition. Since ext4_ext_in_cache() does not initialize newex on misses, bypassing its invocation does not introduce any new issue in this regard. --------- Regards - Eric > > --D >> >> Signed-off-by: Robin Dong <sanbai@taobao.com> >> Reviewed-by: Lukas Czerner <lczerner@redhat.com> >> --- >> 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..fed2633 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) && >> + 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 >> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-ext4" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index eb63c7b..fed2633 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) && + 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) { /*