| Message ID | 1317179380.22361.8.camel@sli10-conroe |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Wed, 2011-09-28 at 11:09 +0800, Shaohua Li wrote: > On Mon, 2011-09-26 at 17:45 +0800, Christoph Hellwig wrote: > > On Mon, Sep 26, 2011 at 03:38:47PM +0800, Shaohua Li wrote: > > > On Mon, 2011-09-26 at 15:30 +0800, Christoph Hellwig wrote: > > > > On Mon, Sep 26, 2011 at 10:30:26AM +0800, Shaohua Li wrote: > > > > > Some filesystems implement .writepages. We don't have blk plug > > > > > in such filesystems for .writepages. > > > > > > > > Please add the plugging in the actual ->writepages instances. > > > there are several filesystems have ->writepages. Can you share an hint > > > why we don't add plugging in the do_writepages? > > > > Because do_writepages is completely generic code with no knowledge of > > block I/O. I really don't want to have block plugging be intimately > > tied into core VM/writeback code all over. We've been there with > > ->sync_page, and it was a major pain - nevermind the additional (small) > > overhead for the not block based filesystems. > I searched a little bit, looks only ext4 need it. here is the patch. > > > Add block plug for ext4 .writepages. Though ext4 .writepages > already handles request merge very well, block plug is still > helpful to reduce block lock contention. > ping > Signed-off-by: Shaohua Li <shaohua.li@intel.com> > > --- > fs/ext4/inode.c | 3 +++ > 1 file changed, 3 insertions(+) > > Index: linux/fs/ext4/inode.c > =================================================================== > --- linux.orig/fs/ext4/inode.c 2011-09-28 10:13:50.000000000 +0800 > +++ linux/fs/ext4/inode.c 2011-09-28 10:23:31.000000000 +0800 > @@ -2046,6 +2046,7 @@ static int ext4_da_writepages(struct add > struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); > pgoff_t done_index = 0; > pgoff_t end; > + struct blk_plug plug; > > trace_ext4_da_writepages(inode, wbc); > > @@ -2124,6 +2125,7 @@ retry: > if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) > tag_pages_for_writeback(mapping, index, end); > > + blk_start_plug(&plug); > while (!ret && wbc->nr_to_write > 0) { > > /* > @@ -2188,6 +2190,7 @@ retry: > */ > break; > } > + blk_finish_plug(&plug); > if (!io_done && !cycled) { > cycled = 1; > index = 0; > -- 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 Wed, Sep 28, 2011 at 11:09:40AM +0800, Shaohua Li wrote: > I searched a little bit, looks only ext4 need it. here is the patch. > > > Add block plug for ext4 .writepages. Though ext4 .writepages > already handles request merge very well, block plug is still > helpful to reduce block lock contention. > > Signed-off-by: Shaohua Li <shaohua.li@intel.com> Thanks, applied. - Ted -- 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
2011/10/11 Ted Ts'o <tytso@mit.edu>: > On Wed, Sep 28, 2011 at 11:09:40AM +0800, Shaohua Li wrote: >> I searched a little bit, looks only ext4 need it. here is the patch. >> >> >> Add block plug for ext4 .writepages. Though ext4 .writepages >> already handles request merge very well, block plug is still >> helpful to reduce block lock contention. >> >> Signed-off-by: Shaohua Li <shaohua.li@intel.com> You found good point. If there are other filesystem that didn't use generic_writepages, these are needed as this patch. Reviewed-by: NamJae Jeon <linkinjeon@gmail.com> > > Thanks, applied. > > - Ted > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- 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 Tue, Oct 11, 2011 at 1:51 AM, Ted Ts'o <tytso@mit.edu> wrote: > On Wed, Sep 28, 2011 at 11:09:40AM +0800, Shaohua Li wrote: >> I searched a little bit, looks only ext4 need it. here is the patch. >> >> >> Add block plug for ext4 .writepages. Though ext4 .writepages >> already handles request merge very well, block plug is still >> helpful to reduce block lock contention. >> >> Signed-off-by: Shaohua Li <shaohua.li@intel.com> Does it require to add blk_finish_plug(&plug) when error case? + blk_start_plug(&plug); while (!ret && wbc->nr_to_write > 0) { ... /* start a new transaction*/ handle = ext4_journal_start(inode, needed_blocks); if (IS_ERR(handle)) { ret = PTR_ERR(handle); ext4_msg(inode->i_sb, KERN_CRIT, "%s: jbd2_start: " "%ld pages, ino %lu; err %d", __func__, wbc->nr_to_write, inode->i_ino, ret); + blk_finish_plug(&plug); goto out_writepages; } Thank you, Kyungmin Park- -- 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
Index: linux/fs/ext4/inode.c =================================================================== --- linux.orig/fs/ext4/inode.c 2011-09-28 10:13:50.000000000 +0800 +++ linux/fs/ext4/inode.c 2011-09-28 10:23:31.000000000 +0800 @@ -2046,6 +2046,7 @@ static int ext4_da_writepages(struct add struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb); pgoff_t done_index = 0; pgoff_t end; + struct blk_plug plug; trace_ext4_da_writepages(inode, wbc); @@ -2124,6 +2125,7 @@ retry: if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages) tag_pages_for_writeback(mapping, index, end); + blk_start_plug(&plug); while (!ret && wbc->nr_to_write > 0) { /* @@ -2188,6 +2190,7 @@ retry: */ break; } + blk_finish_plug(&plug); if (!io_done && !cycled) { cycled = 1; index = 0;