| Subject | Re: [PATCH 11/18] block: add bdi flag to indicate risk of io queue underrun | From | Peter Zijlstra <> | Date | Tue, 06 Sep 2011 16:22:48 +0200 |
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On Sun, 2011-09-04 at 09:53 +0800, Wu Fengguang wrote: > +++ linux-next/mm/page-writeback.c 2011-08-31 14:40:58.000000000 +0800 > @@ -1067,6 +1067,9 @@ static void balance_dirty_pages(struct a > nr_dirty, bdi_thresh, bdi_dirty, > start_time); > > + if (unlikely(!dirty_exceeded && bdi_async_underrun(bdi))) > + break; > + > dirty_ratelimit = bdi->dirty_ratelimit; > pos_ratio = bdi_position_ratio(bdi, dirty_thresh, > background_thresh, nr_dirty,
So dirty_exceeded looks like:
1109 dirty_exceeded = (bdi_dirty > bdi_thresh) || 1110 (nr_dirty > dirty_thresh);
Would it make sense to write it as:
if (nr_dirty > dirty_thresh || (nr_dirty > freerun && bdi_dirty > bdi_thresh)) dirty_exceeded = 1;
So that we don't actually throttle bdi thingies when we're still in the freerun area?
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