RE: [PATCH v3 kernel 0/7] Extend virtio-balloon for fast (de)inflating & fast live migration

["Li, Liang Z" <liang.z.li@intel.com>]

Hi Michael,

Could you help to review this version when you have time? 

Thanks!
Liang

> -----Original Message-----
> From: Li, Liang Z
> Sent: Monday, August 08, 2016 2:35 PM
> To: linux-kernel@vger.kernel.org
> Cc: virtualization@lists.linux-foundation.org; linux-mm@kvack.org; virtio-
> dev@lists.oasis-open.org; kvm@vger.kernel.org; qemu-devel@nongnu.org;
> quintela@redhat.com; dgilbert@redhat.com; Hansen, Dave; Li, Liang Z
> Subject: [PATCH v3 kernel 0/7] Extend virtio-balloon for fast (de)inflating &
> fast live migration
> 
> This patch set contains two parts of changes to the virtio-balloon.
> 
> One is the change for speeding up the inflating & deflating process, the main
> idea of this optimization is to use bitmap to send the page information to
> host instead of the PFNs, to reduce the overhead of virtio data transmission,
> address translation and madvise(). This can help to improve the performance
> by about 85%.
> 
> Another change is for speeding up live migration. By skipping process guest's
> free pages in the first round of data copy, to reduce needless data processing,
> this can help to save quite a lot of CPU cycles and network bandwidth. We
> put guest's free page information in bitmap and send it to host with the virt
> queue of virtio-balloon. For an idle 8GB guest, this can help to shorten the
> total live migration time from 2Sec to about 500ms in the 10Gbps network
> environment.
> 
> Dave Hansen suggested a new scheme to encode the data structure,
> because of additional complexity, it's not implemented in v3.
> 
> Changes from v2 to v3:
>     * Change the name of 'free page' to 'unused page'.
>     * Use the scatter & gather bitmap instead of a 1MB page bitmap.
>     * Fix overwriting the page bitmap after kicking.
>     * Some of MST's comments for v2.
> 
> Changes from v1 to v2:
>     * Abandon the patch for dropping page cache.
>     * Put some structures to uapi head file.
>     * Use a new way to determine the page bitmap size.
>     * Use a unified way to send the free page information with the bitmap
>     * Address the issues referred in MST's comments
> 
> 
> Liang Li (7):
>   virtio-balloon: rework deflate to add page to a list
>   virtio-balloon: define new feature bit and page bitmap head
>   mm: add a function to get the max pfn
>   virtio-balloon: speed up inflate/deflate process
>   mm: add the related functions to get unused page
>   virtio-balloon: define feature bit and head for misc virt queue
>   virtio-balloon: tell host vm's unused page info
> 
>  drivers/virtio/virtio_balloon.c     | 390
> ++++++++++++++++++++++++++++++++----
>  include/linux/mm.h                  |   3 +
>  include/uapi/linux/virtio_balloon.h |  41 ++++
>  mm/page_alloc.c                     |  94 +++++++++
>  4 files changed, 485 insertions(+), 43 deletions(-)
> 
> --
> 1.8.3.1