Messages in this thread | | | Date | Wed, 30 Sep 2009 09:39:36 +1000 | From | Dave Chinner <> | Subject | Re: regression in page writeback |
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On Mon, Sep 28, 2009 at 10:25:24AM -0400, Chris Mason wrote: > On Mon, Sep 28, 2009 at 11:07:00AM +1000, Dave Chinner wrote: > > In the context of the setup I was talking about, I meant is that sync > > IO _should_ be unthrottled because it is self-throttling by it's > > very nature. The current code makes no differentiation between the > > two. > > This isn't entirely true anymore. WB_SYNC_ALL is turned into a sync > bio, which is sent down with higher priority. There may be a few spots > that still need to be changed for it, but it is much better than it was.
Oh, I didn't realise that had changed - when did WRITE_SYNC_PLUG get introduced? FWIW, I notice that __block_write_full_page(), gfs2, btrfs and jdb use WRITE_SYNC_PLUG to implement this, but it appears that filesystems that have their own writeback code (e.g. XFS) have not been converted (gfs2 and btrfs being the exceptions).
Oh well, something else that needs tweaking in XFS...
Cheers,
Dave. -- Dave Chinner david@fromorbit.com
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