Subject: Re: Increase dirty_ratio and dirty_background_ratio?
From: Chris Mason <chris.mason@oracle.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: David Miller <davem@davemloft.net>, akpm@linux-foundation.org,
       peterz@infradead.org, jack@suse.cz, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org, npiggin@suse.de
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Date: Thu, 08 Jan 2009 11:55:01 -0500
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On Thu, 2009-01-08 at 08:48 -0800, Linus Torvalds wrote:
> 
> On Thu, 8 Jan 2009, David Miller wrote:
> 
> > From: Andrew Morton <akpm@linux-foundation.org>
> > Date: Thu, 8 Jan 2009 03:02:45 -0800
> > 
> > > The kernel can't get this right - it doesn't know the usage
> > > patterns/workloads, etc.
> > 
> > I don't agree with that.
> 
> We can certainly try to tune it better. 
> 

Does it make sense to hook into kupdate?  If kupdate finds it can't meet
the no-data-older-than 30 seconds target, it lowers the sync/async combo
down to some reasonable bottom.  

If it finds it is going to sleep without missing the target, raise the
combo up to some reasonable top.

-chris


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