Messages in this thread | | | Date | Tue, 9 Apr 2019 09:37:54 -0400 | From | "Michael S. Tsirkin" <> | Subject | Re: Thoughts on simple scanner approach for free page hinting |
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On Tue, Apr 09, 2019 at 03:36:08PM +0200, David Hildenbrand wrote: > On 09.04.19 15:31, Michael S. Tsirkin wrote: > > On Tue, Apr 09, 2019 at 11:20:36AM +0200, David Hildenbrand wrote: > >> BTW I like the idea of allocating pages that have already been hinted as > >> last "choice", allocating pages that have not been hinted yet first. > > > > OK I guess but note this is just a small window during which > > not all pages have been hinted. > > Yes, good point. It might sound desirable but might be completely > irrelevant in practice. > > > > > So if we actually think this has value then we need > > to design something that will desist and not drop pages > > in steady state too. > > By dropping, you mean dropping hints of e.g. MAX_ORDER - 1 or e.g. not > reporting MAX_ORDER - 3?
I mean the issue is host unmaps the pages from guest right? That is what makes hinted pages slower than non-hinted ones. If we do not want that to happen for some pages, then either host can defer acting on the hint, or we can defer hinting.
> -- > > Thanks, > > David / dhildenb
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