Re: [RFC/T/D][PATCH 2/2] Linux/Guest cooperative unmapped page cachecontrol

[Avi Kivity]

On 06/14/2010 08:40 PM, Balbir Singh wrote:
> * Avi Kivity<avi@xxxxxxxxxx>  [2010-06-14 18:34:58]:
>
>    
> > On 06/14/2010 06:12 PM, Dave Hansen wrote:
> >      
> > > On Mon, 2010-06-14 at 14:18 +0530, Balbir Singh wrote:
> > >        
> > > > 1. A slab page will not be freed until the entire page is free (all
> > > > slabs have been kfree'd so to speak). Normal reclaim will definitely
> > > > free this page, but a lot of it depends on how frequently we are
> > > > scanning the LRU list and when this page got added.
> > > >          
> > > You don't have to be freeing entire slab pages for the reclaim to have
> > > been useful.  You could just be making space so that _future_
> > > allocations fill in the slab holes you just created.  You may not be
> > > freeing pages, but you're reducing future system pressure.
> > >        
> > Depends.  If you've evicted something that will be referenced soon,
> > you're increasing system pressure.
> >
> >      
> I don't think slab pages care about being referenced soon, they are
> either allocated or freed. A page is just a storage unit for the data
> structure. A new one can be allocated on demand.
>    

If we're talking just about slab pages, I agree.  If we're applying 
pressure on the shrinkers, then you are removing live objects which can 
be costly to reinstantiate.


--
error compiling committee.c: too many arguments to function

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