linux-kernel - Re: On guest free page hinting and OOM

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Date:   Tue, 2 Apr 2019 17:57:06 +0200
From:   David Hildenbrand <david@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>,
        Alexander Duyck <alexander.duyck@...il.com>
Cc:     Nitesh Narayan Lal <nitesh@...hat.com>,
        kvm list <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-mm <linux-mm@...ck.org>,
        Paolo Bonzini <pbonzini@...hat.com>, lcapitulino@...hat.com,
        pagupta@...hat.com, wei.w.wang@...el.com,
        Yang Zhang <yang.zhang.wz@...il.com>,
        Rik van Riel <riel@...riel.com>, dodgen@...gle.com,
        Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
        dhildenb@...hat.com, Andrea Arcangeli <aarcange@...hat.com>
Subject: Re: On guest free page hinting and OOM

On 02.04.19 17:25, Michael S. Tsirkin wrote:
> On Tue, Apr 02, 2019 at 08:04:00AM -0700, Alexander Duyck wrote:
>> Basically what we would be doing is providing a means for
>> incrementally transitioning the buddy memory into the idle/offline
>> state to reduce guest memory overhead. It would require one function
>> that would walk the free page lists and pluck out pages that don't
>> have the "Offline" page type set,
> 
> I think we will need an interface that gets
> an offline page and returns the next online free page.
> 
> If we restart the list walk each time we can't guarantee progress.

Yes, and essentially we are scanning all the time for chunks vs. we get
notified which chunks are possible hinting candidates. Totally different
design.


-- 

Thanks,

David / dhildenb