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

From: Avi Kivity
Date: Tue Jun 15 2010 - 03:11:46 EST

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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