lkml.org 
[lkml]   [2018]   [Jul]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v36 0/5] Virtio-balloon: support free page reporting
On Fri, Jul 20, 2018 at 04:33:00PM +0800, Wei Wang wrote:
> This patch series is separated from the previous "Virtio-balloon
> Enhancement" series. The new feature, VIRTIO_BALLOON_F_FREE_PAGE_HINT,
> implemented by this series enables the virtio-balloon driver to report
> hints of guest free pages to the host. It can be used to accelerate live
> migration of VMs. Here is an introduction of this usage:
>
> Live migration needs to transfer the VM's memory from the source machine
> to the destination round by round. For the 1st round, all the VM's memory
> is transferred. From the 2nd round, only the pieces of memory that were
> written by the guest (after the 1st round) are transferred. One method
> that is popularly used by the hypervisor to track which part of memory is
> written is to write-protect all the guest memory.
>
> This feature enables the optimization by skipping the transfer of guest
> free pages during VM live migration. It is not concerned that the memory
> pages are used after they are given to the hypervisor as a hint of the
> free pages, because they will be tracked by the hypervisor and transferred
> in the subsequent round if they are used and written.
>
> * Tests
> - Test Environment
> Host: Intel(R) Xeon(R) CPU E5-2699 v4 @ 2.20GHz
> Guest: 8G RAM, 4 vCPU
> Migration setup: migrate_set_speed 100G, migrate_set_downtime 2 second

Can we split out patches 1 and 2? They seem appropriate for this
release ...

> - Test Results
> - Idle Guest Live Migration Time (results are averaged over 10 runs):
> - Optimization v.s. Legacy = 409ms vs 1757ms --> ~77% reduction
> (setting page poisoning zero and enabling ksm don't affect the
> comparison result)
> - Guest with Linux Compilation Workload (make bzImage -j4):
> - Live Migration Time (average)
> Optimization v.s. Legacy = 1407ms v.s. 2528ms --> ~44% reduction
> - Linux Compilation Time
> Optimization v.s. Legacy = 5min4s v.s. 5min12s
> --> no obvious difference
>
> ChangeLog:
> v35->v36:
> - remove the mm patch, as Linus has a suggestion to get free page
> addresses via allocation, instead of reading from the free page
> list.
> - virtio-balloon:
> - replace oom notifier with shrinker;
> - the guest to host communication interface remains the same as
> v32.
> - allocate free page blocks and send to host one by one, and free
> them after sending all the pages.
>
> For ChangeLogs from v22 to v35, please reference
> https://lwn.net/Articles/759413/
>
> For ChangeLogs before v21, please reference
> https://lwn.net/Articles/743660/
>
> Wei Wang (5):
> virtio-balloon: remove BUG() in init_vqs
> virtio_balloon: replace oom notifier with shrinker
> virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
> mm/page_poison: expose page_poisoning_enabled to kernel modules
> virtio-balloon: VIRTIO_BALLOON_F_PAGE_POISON
>
> drivers/virtio/virtio_balloon.c | 456 ++++++++++++++++++++++++++++++------
> include/uapi/linux/virtio_balloon.h | 7 +
> mm/page_poison.c | 6 +
> 3 files changed, 394 insertions(+), 75 deletions(-)
>
> --
> 2.7.4

\
 
 \ /
  Last update: 2018-07-20 14:52    [W:0.145 / U:4.896 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site