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Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on t
From: |
David Hildenbrand |
Subject: |
Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list |
Date: |
Tue, 20 Jun 2017 18:49:33 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 |
On 20.06.2017 18:44, Rik van Riel wrote:
> On Mon, 2017-06-12 at 07:10 -0700, Dave Hansen wrote:
>
>> The hypervisor is going to throw away the contents of these pages,
>> right? As soon as the spinlock is released, someone can allocate a
>> page, and put good data in it. What keeps the hypervisor from
>> throwing
>> away good data?
>
> That looks like it may be the wrong API, then?
>
> We already have hooks called arch_free_page and
> arch_alloc_page in the VM, which are called when
> pages are freed, and allocated, respectively.
>
> Nitesh Lal (on the CC list) is working on a way
> to efficiently batch recently freed pages for
> free page hinting to the hypervisor.
>
> If that is done efficiently enough (eg. with
> MADV_FREE on the hypervisor side for lazy freeing,
> and lazy later re-use of the pages), do we still
> need the harder to use batch interface from this
> patch?
>
David's opinion incoming:
No, I think proper free page hinting would be the optimum solution, if
done right. This would avoid the batch interface and even turn
virtio-balloon in some sense useless.
--
Thanks,
David
- [Qemu-devel] [PATCH v11 1/6] virtio-balloon: deflate via a page list, (continued)
- [Qemu-devel] [PATCH v11 1/6] virtio-balloon: deflate via a page list, Wei Wang, 2017/06/09
- [Qemu-devel] [PATCH v11 2/6] virtio-balloon: coding format cleanup, Wei Wang, 2017/06/09
- [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Wei Wang, 2017/06/09
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Dave Hansen, 2017/06/12
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Michael S. Tsirkin, 2017/06/12
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Dave Hansen, 2017/06/12
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Michael S. Tsirkin, 2017/06/12
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Dave Hansen, 2017/06/12
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Wei Wang, 2017/06/12
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Rik van Riel, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list,
David Hildenbrand <=
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Rik van Riel, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Michael S. Tsirkin, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Rik van Riel, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Michael S. Tsirkin, 2017/06/21
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Wei Wang, 2017/06/21
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Michael S. Tsirkin, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, David Hildenbrand, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Michael S. Tsirkin, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, David Hildenbrand, 2017/06/20
- Re: [Qemu-devel] [PATCH v11 4/6] mm: function to offer a page block on the free list, Christian Borntraeger, 2017/06/21