From: "Michael S. Tsirkin" <mst@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Wei Wang <wei.w.wang@intel.com>,
virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, david@redhat.com,
dave.hansen@intel.com, cornelia.huck@de.ibm.com,
akpm@linux-foundation.org, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
liliang.opensource@gmail.com
Subject: Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration
Date: Fri, 14 Apr 2017 04:50:48 +0300 [thread overview]
Message-ID: <20170414044515-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20170413204411.GJ784@bombadil.infradead.org>
On Thu, Apr 13, 2017 at 01:44:11PM -0700, Matthew Wilcox wrote:
> On Thu, Apr 13, 2017 at 05:35:03PM +0800, Wei Wang wrote:
> > 2) transfer the guest unused pages to the host so that they
> > can be skipped to migrate in live migration.
>
> I don't understand this second bit. You leave the pages on the free list,
> and tell the host they're free. What's preventing somebody else from
> allocating them and using them for something? Is the guest semi-frozen
> at this point with just enough of it running to ask the balloon driver
> to do things?
There's missing documentation here.
The way things actually work is host sends to guest
a request for unused pages and then write-protects all memory.
So guest isn't frozen but any changes will be detected by host.
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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Wei Wang <wei.w.wang@intel.com>,
virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, david@redhat.com,
dave.hansen@intel.com, cornelia.huck@de.ibm.com,
akpm@linux-foundation.org, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
liliang.opensource@gmail.com
Subject: Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration
Date: Fri, 14 Apr 2017 04:50:48 +0300 [thread overview]
Message-ID: <20170414044515-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20170413204411.GJ784@bombadil.infradead.org>
On Thu, Apr 13, 2017 at 01:44:11PM -0700, Matthew Wilcox wrote:
> On Thu, Apr 13, 2017 at 05:35:03PM +0800, Wei Wang wrote:
> > 2) transfer the guest unused pages to the host so that they
> > can be skipped to migrate in live migration.
>
> I don't understand this second bit. You leave the pages on the free list,
> and tell the host they're free. What's preventing somebody else from
> allocating them and using them for something? Is the guest semi-frozen
> at this point with just enough of it running to ask the balloon driver
> to do things?
There's missing documentation here.
The way things actually work is host sends to guest
a request for unused pages and then write-protects all memory.
So guest isn't frozen but any changes will be detected by host.
WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Wei Wang <wei.w.wang@intel.com>,
virtio-dev@lists.oasis-open.org, linux-kernel@vger.kernel.org,
qemu-devel@nongnu.org, virtualization@lists.linux-foundation.org,
kvm@vger.kernel.org, linux-mm@kvack.org, david@redhat.com,
dave.hansen@intel.com, cornelia.huck@de.ibm.com,
akpm@linux-foundation.org, mgorman@techsingularity.net,
aarcange@redhat.com, amit.shah@redhat.com, pbonzini@redhat.com,
liliang.opensource@gmail.com
Subject: Re: [Qemu-devel] [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration
Date: Fri, 14 Apr 2017 04:50:48 +0300 [thread overview]
Message-ID: <20170414044515-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20170413204411.GJ784@bombadil.infradead.org>
On Thu, Apr 13, 2017 at 01:44:11PM -0700, Matthew Wilcox wrote:
> On Thu, Apr 13, 2017 at 05:35:03PM +0800, Wei Wang wrote:
> > 2) transfer the guest unused pages to the host so that they
> > can be skipped to migrate in live migration.
>
> I don't understand this second bit. You leave the pages on the free list,
> and tell the host they're free. What's preventing somebody else from
> allocating them and using them for something? Is the guest semi-frozen
> at this point with just enough of it running to ask the balloon driver
> to do things?
There's missing documentation here.
The way things actually work is host sends to guest
a request for unused pages and then write-protects all memory.
So guest isn't frozen but any changes will be detected by host.
next prev parent reply other threads:[~2017-04-14 1:50 UTC|newest]
Thread overview: 135+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-13 9:35 [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Wei Wang
2017-04-13 9:35 ` [Qemu-devel] " Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [PATCH v9 1/5] virtio-balloon: deflate via a page list Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [Qemu-devel] " Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS Wei Wang
2017-04-13 9:35 ` [Qemu-devel] " Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 16:34 ` Michael S. Tsirkin
2017-04-13 16:34 ` Michael S. Tsirkin
2017-04-13 16:34 ` [Qemu-devel] " Michael S. Tsirkin
2017-04-13 16:34 ` Michael S. Tsirkin
2017-04-13 17:03 ` Matthew Wilcox
2017-04-13 17:03 ` Matthew Wilcox
2017-04-13 17:03 ` [Qemu-devel] " Matthew Wilcox
2017-04-13 17:03 ` Matthew Wilcox
2017-04-14 8:37 ` Wei Wang
2017-04-14 8:37 ` [Qemu-devel] [virtio-dev] " Wei Wang
2017-04-14 8:37 ` Wei Wang
2017-04-14 8:37 ` Wei Wang
2017-04-14 21:38 ` Michael S. Tsirkin
2017-04-14 21:38 ` [Qemu-devel] [virtio-dev] " Michael S. Tsirkin
2017-04-14 21:38 ` Michael S. Tsirkin
2017-04-14 21:38 ` Michael S. Tsirkin
2017-04-17 3:35 ` Wei Wang
2017-04-17 3:35 ` [Qemu-devel] [virtio-dev] " Wei Wang
2017-04-17 3:35 ` Wei Wang
2017-04-17 3:35 ` Wei Wang
2017-04-26 11:03 ` Wang, Wei W
2017-04-26 11:03 ` Wang, Wei W
2017-04-26 11:03 ` [Qemu-devel] [virtio-dev] " Wang, Wei W
2017-04-26 11:03 ` Wang, Wei W
2017-04-26 11:03 ` Wang, Wei W
2017-04-26 23:20 ` Michael S. Tsirkin
2017-04-26 23:20 ` Michael S. Tsirkin
2017-04-26 23:20 ` [Qemu-devel] " Michael S. Tsirkin
2017-04-26 23:20 ` Michael S. Tsirkin
2017-04-27 6:31 ` Wei Wang
2017-04-27 6:31 ` [Qemu-devel] " Wei Wang
2017-04-27 6:31 ` Wei Wang
2017-05-05 22:25 ` Michael S. Tsirkin
2017-05-05 22:25 ` Michael S. Tsirkin
2017-05-05 22:25 ` [Qemu-devel] [virtio-dev] " Michael S. Tsirkin
2017-05-05 22:25 ` Michael S. Tsirkin
2017-05-05 22:25 ` Michael S. Tsirkin
2017-05-07 4:19 ` Wang, Wei W
2017-05-07 4:19 ` Wang, Wei W
2017-05-07 4:19 ` [Qemu-devel] [virtio-dev] " Wang, Wei W
2017-05-07 4:19 ` Wang, Wei W
2017-05-07 4:19 ` Wang, Wei W
2017-05-08 17:40 ` Michael S. Tsirkin
2017-05-08 17:40 ` [Qemu-devel] [virtio-dev] " Michael S. Tsirkin
2017-05-08 17:40 ` Michael S. Tsirkin
2017-05-08 17:40 ` Michael S. Tsirkin
2017-05-09 2:45 ` Wei Wang
2017-05-09 2:45 ` Wei Wang
2017-05-09 2:45 ` [Qemu-devel] " Wei Wang
2017-05-09 2:45 ` Wei Wang
2017-05-08 17:40 ` Michael S. Tsirkin
2017-04-27 6:31 ` Wei Wang
2017-04-17 3:35 ` Wei Wang
2017-04-14 21:38 ` Michael S. Tsirkin
2017-04-14 8:37 ` Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [PATCH v9 3/5] mm: function to offer a page block on the free list Wei Wang
2017-04-13 9:35 ` [Qemu-devel] " Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 20:02 ` Andrew Morton
2017-04-13 20:02 ` [Qemu-devel] " Andrew Morton
2017-04-13 20:02 ` Andrew Morton
2017-04-13 20:02 ` Andrew Morton
2017-04-14 2:30 ` Wei Wang
2017-04-14 2:30 ` [Qemu-devel] " Wei Wang
2017-04-14 2:30 ` Wei Wang
2017-04-14 2:58 ` Matthew Wilcox
2017-04-14 2:58 ` [Qemu-devel] " Matthew Wilcox
2017-04-14 2:58 ` Matthew Wilcox
2017-04-14 8:58 ` Wei Wang
2017-04-14 8:58 ` [Qemu-devel] " Wei Wang
2017-04-14 8:58 ` Wei Wang
2017-04-14 8:58 ` Wei Wang
2017-04-14 2:58 ` Matthew Wilcox
2017-04-14 2:30 ` Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [PATCH v9 4/5] mm: export symbol of next_zone and first_online_pgdat Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [Qemu-devel] " Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 9:35 ` [PATCH v9 5/5] virtio-balloon: VIRTIO_BALLOON_F_MISC_VQ Wei Wang
2017-04-13 9:35 ` [Qemu-devel] " Wei Wang
2017-04-13 9:35 ` Wei Wang
2017-04-13 17:08 ` Michael S. Tsirkin
2017-04-13 17:08 ` [Qemu-devel] " Michael S. Tsirkin
2017-04-13 17:08 ` Michael S. Tsirkin
2017-04-27 6:33 ` Wei Wang
2017-04-27 6:33 ` Wei Wang
2017-04-27 6:33 ` [Qemu-devel] " Wei Wang
2017-04-27 6:33 ` Wei Wang
2017-05-05 22:21 ` Michael S. Tsirkin
2017-05-05 22:21 ` Michael S. Tsirkin
2017-05-05 22:21 ` [Qemu-devel] " Michael S. Tsirkin
2017-05-05 22:21 ` Michael S. Tsirkin
2017-05-07 4:20 ` Wang, Wei W
2017-05-07 4:20 ` [Qemu-devel] " Wang, Wei W
2017-05-07 4:20 ` Wang, Wei W
2017-05-07 4:20 ` Wang, Wei W
2017-04-13 17:08 ` Michael S. Tsirkin
2017-04-13 9:35 ` Wei Wang
2017-04-13 20:44 ` [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Matthew Wilcox
2017-04-13 20:44 ` [Qemu-devel] " Matthew Wilcox
2017-04-13 20:44 ` Matthew Wilcox
2017-04-13 20:44 ` Matthew Wilcox
2017-04-14 1:50 ` Michael S. Tsirkin [this message]
2017-04-14 1:50 ` [Qemu-devel] " Michael S. Tsirkin
2017-04-14 1:50 ` Michael S. Tsirkin
2017-04-14 2:28 ` Wei Wang
2017-04-14 2:28 ` Wei Wang
2017-04-14 2:28 ` [Qemu-devel] " Wei Wang
2017-04-14 2:28 ` Wei Wang
2017-04-14 2:57 ` Michael S. Tsirkin
2017-04-14 2:57 ` Michael S. Tsirkin
2017-04-14 2:57 ` [Qemu-devel] " Michael S. Tsirkin
2017-04-14 2:57 ` Michael S. Tsirkin
2017-04-14 9:47 ` Matthew Wilcox
2017-04-14 9:47 ` [Qemu-devel] " Matthew Wilcox
2017-04-14 9:47 ` Matthew Wilcox
2017-04-14 14:22 ` Michael S. Tsirkin
2017-04-14 14:22 ` Michael S. Tsirkin
2017-04-14 14:22 ` [Qemu-devel] " Michael S. Tsirkin
2017-04-14 14:22 ` Michael S. Tsirkin
2017-04-14 9:47 ` Matthew Wilcox
2017-04-14 1:50 ` Michael S. Tsirkin
-- strict thread matches above, loose matches on Subject: below --
2017-04-13 9:35 Wei Wang
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