| Message ID | 20170825001948.7759-1-bo.li.liu@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Aug 24, 2017 at 06:19:48PM -0600, Liu Bo wrote: > This updates btrfs to use the helper wbc_to_write_flags which has been > applied in ext4/xfs/f2fs/block. Added in commit 7637241e651ec36e4094 in 11/2016, I wonder why btrfs wasn't been changed as well as it uses the same code patterns as the other filesystems. > Please note that, with this, btrfs's dirty pages written by a > writeback job will carry the flag REQ_BACKGROUND, which is currently > used by writeback-throttle to determine whether it should go to get a > request or wait. Which in my understanding of the WBT behaviour is what we want, right? > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> I'm still expecting some surprises (== performance drop) from the recent WBT changes, as we still may miss some request flags, but more subtle than eg. the superblock REQ_ tags. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" 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 06, 2017 at 04:38:06PM +0200, David Sterba wrote: > On Thu, Aug 24, 2017 at 06:19:48PM -0600, Liu Bo wrote: > > This updates btrfs to use the helper wbc_to_write_flags which has been > > applied in ext4/xfs/f2fs/block. > > Added in commit 7637241e651ec36e4094 in 11/2016, I wonder why btrfs > wasn't been changed as well as it uses the same code patterns as the > other filesystems. > /me is curious, too. > > Please note that, with this, btrfs's dirty pages written by a > > writeback job will carry the flag REQ_BACKGROUND, which is currently > > used by writeback-throttle to determine whether it should go to get a > > request or wait. > > Which in my understanding of the WBT behaviour is what we want, right? > Yes, it gives a hint to WBT whether it should wait or not. > > Signed-off-by: Liu Bo <bo.li.liu@oracle.com> > > Reviewed-by: David Sterba <dsterba@suse.com> > > I'm still expecting some surprises (== performance drop) from the recent > WBT changes, as we still may miss some request flags, but more subtle > than eg. the superblock REQ_ tags. Looks like this is the only missing flag I could find, the missing REQ_META (in another patch) doesn't have an impact on WBT. thanks, -liubo -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" 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/btrfs/extent_io.c b/fs/btrfs/extent_io.c index a454a10..825fad6 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -3467,8 +3467,7 @@ static int __extent_writepage(struct page *page, struct writeback_control *wbc, int write_flags = 0; unsigned long nr_written = 0; - if (wbc->sync_mode == WB_SYNC_ALL) - write_flags = REQ_SYNC; + write_flags = wbc_to_write_flags(wbc); trace___extent_writepage(page, inode, wbc); @@ -3713,7 +3712,7 @@ static noinline_for_stack int write_one_eb(struct extent_buffer *eb, u32 nritems; unsigned long i, num_pages; unsigned long start, end; - int write_flags = (epd->sync_io ? REQ_SYNC : 0) | REQ_META; + int write_flags = wbc_to_write_flags(wbc) | REQ_META; int ret = 0; clear_bit(EXTENT_BUFFER_WRITE_ERR, &eb->bflags);
This updates btrfs to use the helper wbc_to_write_flags which has been applied in ext4/xfs/f2fs/block. Please note that, with this, btrfs's dirty pages written by a writeback job will carry the flag REQ_BACKGROUND, which is currently used by writeback-throttle to determine whether it should go to get a request or wait. Signed-off-by: Liu Bo <bo.li.liu@oracle.com> --- fs/btrfs/extent_io.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-)