Re: [PATCH 2/4] xen: introduce an "scrub" free page list

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Jun 18, 2014 at 08:54:00AM +0800, Bob Liu wrote:
> 
> On 06/17/2014 08:36 PM, Jan Beulich wrote:
> >>>> On 17.06.14 at 13:49, <lliubbo@gmail.com> wrote:
> >> Because of page scrubbing, it's very slow to destroy a domain with large 
> >> memory.
> >> It takes around 10 minutes when destroy a guest of nearly 1 TB of memory.
> >>
> >> This patch introduced a "scrub" free page list, pages on this list need to be
> >> scrubbed before use. During domain destory just mark pages "PGC_need_scrub"
> >> and then add them to this list, so that xl can return quickly.
> >>
> >> In alloc_domheap_pages():
> >>   - If there are pages on the normal "heap" freelist, allocate them.
> >>   - Try to allocate from the "scrub" free list with the same order and do
> >>     scrubbing synchronously.
> >>
> >> In order to not fail high order allocate request, merge page trunks for
> >> PGC_need_scrub pages.
> >> Note: PCG_need_scrub pages and normal pages are not mergeable
> > 
> > The whole series needs sync-ing logically both with Konrad's recent
> > boot time scrubbing changes (this change here really makes his
> > change unnecessary - the affected pages could quite well be simply
> > marked as needing scrubbing, getting dealt with by the logic added
> > here) and with XSA-100's change.
> > 
> 
> I agree. Konrad?

The patch is already in staging. See 7430a86de0c9bd126b441570e459f6e06413cbf6
and 4bd78937ec324bcef4e29ef951e0ff9815770de1.

Thanks!