From: Liang Li <liang.z.li@intel.com>
To: kvm@vger.kernel.org
Cc: virtio-dev@lists.oasis-open.org, qemu-devel@nongun.org,
linux-kernel@vger.kernel.org, mst@redhat.com,
Liang Li <liang.z.li@intel.com>
Subject: [PATCH 0/6] Fast balloon & fast live migration
Date: Mon, 13 Jun 2016 17:47:07 +0800 [thread overview]
Message-ID: <1465811233-21136-1-git-send-email-liang.z.li@intel.com> (raw)
The implementation of the current virtio-balloon is not very
efficient, bellow is test result of time spends on inflating
the balloon to 3GB of a 4GB idle guest:
a. allocating pages (6.5%, 103ms)
b. sending PFNs to host (68.3%, 787ms)
c. address translation (6.1%, 96ms)
d. madvise (19%, 300ms)
It takes about 1577ms for the whole inflating process to complete.
The test shows that the bottle neck is the stage b and stage d.
If using a bitmap to send the page info instead of the PFNs, we
can reduce the overhead in stage b quite a lot. Furthermore, it's
possible to do the address translation and the madvise with a bulk
of pages, instead of the current page per page way, so the overhead
of stage c and stage d can also be reduced a lot.
In addition, we can speed up live migration by skipping process
guest's free pages.
Patch 1 and patch 2 are the kernel side implementation which are
intended to speed up the inflating & deflating process by adding a
new feature to the virtio-balloon device. And now, inflating the
balloon to 3GB of a 4GB idle guest only takes 200ms, it's about 8
times as fast as before.
Patch 3 and patch 4 add the cache drop support, now hypervisor can
request the guest to drop it's cache. It's useful before inflating
the virtio-balloon and before starting live migration.
Patch 5 and patch 6 save guest's free page information into a page
bitmap and send the bitmap to host through balloon's virt queue.
Liang Li (6):
virtio-balloon: rework deflate to add page to a list
virtio-balloon: speed up inflate/deflate process
mm:split the drop cache operation into a function
virtio-balloon: add drop cache support
mm: add the related functions to get free page info
virtio-balloon: tell host vm's free page info
drivers/virtio/virtio_balloon.c | 321 +++++++++++++++++++++++++++++++-----
fs/drop_caches.c | 22 ++-
include/linux/mm.h | 1 +
include/uapi/linux/virtio_balloon.h | 2 +
mm/page_alloc.c | 40 +++++
5 files changed, 339 insertions(+), 47 deletions(-)
--
1.9.1
next reply other threads:[~2016-06-13 9:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-13 9:47 Liang Li [this message]
2016-06-13 9:47 ` [PATCH 1/6] virtio-balloon: rework deflate to add page to a list Liang Li
2016-06-23 8:25 ` Li, Liang Z
2016-06-23 8:30 ` Li, Liang Z
2016-06-13 9:47 ` [PATCH 2/6] virtio-balloon: speed up inflate/deflate process Liang Li
2016-06-13 10:17 ` kbuild test robot
2016-06-24 5:39 ` Michael S. Tsirkin
2016-06-24 6:28 ` Li, Liang Z
2016-06-13 9:47 ` [PATCH 3/6] mm:split the drop cache operation into a function Liang Li
2016-06-13 9:47 ` [PATCH 4/6] virtio-balloon: add drop cache support Liang Li
2016-06-13 9:47 ` [PATCH 5/6] mm: add the related functions to get free page info Liang Li
2016-06-13 9:47 ` [PATCH 6/6] virtio-balloon: tell host vm's " Liang Li
2016-06-23 8:27 ` [PATCH 0/6] Fast balloon & fast live migration Li, Liang Z
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