Re: [PATCH v12 0/8] Virtio-balloon Enhancement

[Michael S. Tsirkin]

On Wed, Jul 12, 2017 at 08:40:13PM +0800, Wei Wang wrote:
> This patch series enhances the existing virtio-balloon with the following new
> features:
> 1) fast ballooning: transfer ballooned pages between the guest and host in
> chunks using sgs, instead of one by one; and
> 2) cmdq: a new virtqueue to send commands between the device and driver.
> Currently, it supports commands to report memory stats (replace the old statq
> mechanism) and report guest unused pages.

Could we get some feedback from mm crowd on patches 6 and 7?

> Change Log:
> 
> v11->v12:
> 1) xbitmap: use the xbitmap from Matthew Wilcox to record ballooned pages.
> 2) virtio-ring: enable the driver to build up a desc chain using vring desc.
> 3) virtio-ring: Add locking to the existing START_USE() and END_USE() macro
> to lock/unlock the vq when a vq operation starts/ends.
> 4) virtio-ring: add virtqueue_kick_sync() and virtqueue_kick_async()
> 5) virtio-balloon: describe chunks of ballooned pages and free pages blocks
> directly using one or more chains of desc from the vq.
> 
> v10->v11:
> 1) virtio_balloon: use vring_desc to describe a chunk;
> 2) virtio_ring: support to add an indirect desc table to virtqueue;
> 3)  virtio_balloon: use cmdq to report guest memory statistics.
> 
> v9->v10:
> 1) mm: put report_unused_page_block() under CONFIG_VIRTIO_BALLOON;
> 2) virtio-balloon: add virtballoon_validate();
> 3) virtio-balloon: msg format change;
> 4) virtio-balloon: move miscq handling to a task on system_freezable_wq;
> 5) virtio-balloon: code cleanup.
> 
> v8->v9:
> 1) Split the two new features, VIRTIO_BALLOON_F_BALLOON_CHUNKS and
> VIRTIO_BALLOON_F_MISC_VQ, which were mixed together in the previous
> implementation;
> 2) Simpler function to get the free page block.
> 
> v7->v8:
> 1) Use only one chunk format, instead of two.
> 2) re-write the virtio-balloon implementation patch.
> 3) commit changes
> 4) patch re-org
> 
> Liang Li (1):
>   virtio-balloon: deflate via a page list
> 
> Matthew Wilcox (1):
>   Introduce xbitmap
> 
> Wei Wang (6):
>   virtio-balloon: coding format cleanup
>   xbitmap: add xb_find_next_bit() and xb_zero()
>   virtio-balloon: VIRTIO_BALLOON_F_SG
>   mm: support reporting free page blocks
>   mm: export symbol of next_zone and first_online_pgdat
>   virtio-balloon: VIRTIO_BALLOON_F_CMD_VQ
> 
>  drivers/virtio/virtio_balloon.c     | 414 ++++++++++++++++++++++++++++++++----
>  drivers/virtio/virtio_ring.c        | 224 +++++++++++++++++--
>  include/linux/mm.h                  |   5 +
>  include/linux/radix-tree.h          |   2 +
>  include/linux/virtio.h              |  22 ++
>  include/linux/xbitmap.h             |  53 +++++
>  include/uapi/linux/virtio_balloon.h |  11 +
>  lib/radix-tree.c                    | 164 +++++++++++++-
>  mm/mmzone.c                         |   2 +
>  mm/page_alloc.c                     |  96 +++++++++
>  10 files changed, 926 insertions(+), 67 deletions(-)
>  create mode 100644 include/linux/xbitmap.h
> 
> -- 
> 2.7.4