Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1623617

Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration

Show all headers | View raw

On Fri, Apr 14, 2017 at 04:50:48AM +0300, Michael S. Tsirkin wrote:
> 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.

... hopefully you mean "write protects all memory, then sends a request
for unused pages", otherwise there's a race condition.

And I see the utility of this, but does this functionality belong in
the balloon driver?  It seems like it's something you might want even
if you don't have the balloon driver loaded.  Or something you might
not want if you do have the balloon driver loaded.

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating & fast live migration Wei Wang <wei.w.wang@intel.com> - 2017-04-13 11:50 +0200
  [PATCH v9 5/5] virtio-balloon: VIRTIO_BALLOON_F_MISC_VQ Wei Wang <wei.w.wang@intel.com> - 2017-04-13 11:50 +0200
    Re: [PATCH v9 5/5] virtio-balloon: VIRTIO_BALLOON_F_MISC_VQ "Michael S. Tsirkin" <mst@redhat.com> - 2017-04-13 19:10 +0200
  [PATCH v9 3/5] mm: function to offer a page block on the free list Wei Wang <wei.w.wang@intel.com> - 2017-04-13 11:50 +0200
    Re: [PATCH v9 3/5] mm: function to offer a page block on the free  list Andrew Morton <akpm@linux-foundation.org> - 2017-04-13 22:10 +0200
      Re: [PATCH v9 3/5] mm: function to offer a page block on the free  list Wei Wang <wei.w.wang@intel.com> - 2017-04-14 04:30 +0200
        Re: [PATCH v9 3/5] mm: function to offer a page block on the free  list Matthew Wilcox <willy@infradead.org> - 2017-04-14 05:00 +0200
          Re: [PATCH v9 3/5] mm: function to offer a page block on the free  list Wei Wang <wei.w.wang@intel.com> - 2017-04-14 11:00 +0200
  [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS Wei Wang <wei.w.wang@intel.com> - 2017-04-13 11:50 +0200
    Re: [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS "Michael S. Tsirkin" <mst@redhat.com> - 2017-04-13 18:40 +0200
      Re: [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS Matthew Wilcox <willy@infradead.org> - 2017-04-13 19:10 +0200
      Re: [virtio-dev] Re: [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS Wei Wang <wei.w.wang@intel.com> - 2017-04-14 10:40 +0200
        Re: [virtio-dev] Re: [PATCH v9 2/5] virtio-balloon:  VIRTIO_BALLOON_F_BALLOON_CHUNKS "Michael S. Tsirkin" <mst@redhat.com> - 2017-04-14 23:40 +0200
          Re: [virtio-dev] Re: [PATCH v9 2/5] virtio-balloon: VIRTIO_BALLOON_F_BALLOON_CHUNKS Wei Wang <wei.w.wang@intel.com> - 2017-04-17 05:40 +0200
  Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating &  fast live migration Matthew Wilcox <willy@infradead.org> - 2017-04-13 22:50 +0200
    Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating &  fast live migration "Michael S. Tsirkin" <mst@redhat.com> - 2017-04-14 04:00 +0200
      Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating &  fast live migration Wei Wang <wei.w.wang@intel.com> - 2017-04-14 04:30 +0200
        Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating &  fast live migration "Michael S. Tsirkin" <mst@redhat.com> - 2017-04-14 05:00 +0200
      Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating &  fast live migration Matthew Wilcox <willy@infradead.org> - 2017-04-14 11:50 +0200
        Re: [PATCH v9 0/5] Extend virtio-balloon for fast (de)inflating &  fast live migration "Michael S. Tsirkin" <mst@redhat.com> - 2017-04-14 16:30 +0200

csiph-web