Re: [PATCH 1/2] vmscan: fix initial shrinker size handling

[Dave Chinner]

On Mon, Aug 22, 2011 at 02:30:06PM -0700, Andrew Morton wrote:
> On Mon, 22 Aug 2011 14:17:21 +0300
> Konstantin Khlebnikov <khlebnikov@xxxxxxxxxx> wrote:
> 
> > Shrinker function can returns -1, it means it cannot do anything without a risk of deadlock.
> > For example prune_super() do this if it cannot grab superblock refrence, even if nr_to_scan=0.
> > Currenly we interpret this like ULONG_MAX size shrinker, evaluate total_scan according this,
> > and next time this shrinker can get really big pressure. Let's skip such shrinkers instead.
> 
> Yes, that looks like a significant oversight.
> 
> > Also make total_scan signed, otherwise check (total_scan < 0) below never works.
> 
> Hopefully a smaller oversight.

Yeah, it was, but is harmless because it is caught by the next check
of total_scanned. I've made similar "make everything signed" changes
as well.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
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