Messages in this thread | | | Subject | Re: bdi_threshold slow to reach steady state | From | Peter Zijlstra <> | Date | Wed, 14 Oct 2009 16:04:32 +0200 |
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On Wed, 2009-10-14 at 14:55 +0100, Richard Kennedy wrote: > > commit 11735a2336ba08cf21aebf79a706c86aca5e44b2 > Author: Richard Kennedy <richard@rsk.demon.co.uk> > Date: Wed Oct 14 14:46:21 2009 +0100 > > mm: speed up per bdi dirty threshold calculations
I think the subject is confusing, we don't actually compute things faster in the less cycles sense.
We reduce the dampening for the control system, yielding faster convergence.
> Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> > > diff --git a/mm/page-writeback.c b/mm/page-writeback.c > index a3b1409..018024e 100644 > --- a/mm/page-writeback.c > +++ b/mm/page-writeback.c > @@ -144,7 +144,7 @@ static int calc_period_shift(void) > else > dirty_total = (vm_dirty_ratio * > determine_dirtyable_memory()) / > 100; > - return 2 + ilog2(dirty_total - 1); > + return ilog2(dirty_total - 1) - 2; > }
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