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Re: [Qemu-devel] [PATCH v2 0/3] virtio-balloon: free page hint reporting
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/3] virtio-balloon: free page hint reporting support |
Date: |
Thu, 8 Feb 2018 20:15:24 +0000 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
* Wei Wang (address@hidden) wrote:
> This is the deivce part implementation to add a new feature,
> VIRTIO_BALLOON_F_FREE_PAGE_HINT to the virtio-balloon device. The device
> receives the guest free page hints from the driver and clears the
> corresponding bits in the dirty bitmap, so that those free pages are
> not transferred by the migration thread to the destination.
>
> Please see the driver patch link for test results:
> https://lkml.org/lkml/2018/2/4/60
Hi Wei,
I'll look at the code a bit more - but first some more basic
questions on that lkml post:
a) The idle guest time thing is a nice result; can you just state
what the host was, speed of connection, and what other options
you were using?
b) The workload test, the one with the kernel compile; you list
the kernel compile time but don't mention any changes in the
migration times of the ping-pong; can you give those times as
well?
c) What's your real workload that this is aimed at?
Is it really for people migrating idle VMs - or do you have some
NFV application in mind, if so why not include a figure for
those?
Thanks,
Dave
> ChangeLog:
> v1->v2:
> 1) virtio-balloon
> - use subsections to save free_page_report_cmd_id;
> - poll the free page vq after sending a cmd id to the driver;
> - change the free page vq size to VIRTQUEUE_MAX_SIZE;
> - virtio_balloon_poll_free_page_hints: handle the corner case
> that the free page block reported from the driver may cross
> the RAMBlock boundary.
> 2) migration/ram.c
> - use balloon_free_page_poll to start the optimization
>
> Wei Wang (3):
> virtio-balloon: VIRTIO_BALLOON_F_FREE_PAGE_HINT
> migration: use the free page reporting feature from balloon
> virtio-balloon: add a timer to limit the free page report waiting time
>
> balloon.c | 39 ++--
> hw/virtio/virtio-balloon.c | 227
> ++++++++++++++++++++++--
> hw/virtio/virtio-pci.c | 3 +
> include/hw/virtio/virtio-balloon.h | 15 +-
> include/migration/misc.h | 3 +
> include/standard-headers/linux/virtio_balloon.h | 7 +
> include/sysemu/balloon.h | 12 +-
> migration/ram.c | 34 +++-
> 8 files changed, 307 insertions(+), 33 deletions(-)
>
> --
> 1.8.3.1
>
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH v2 2/3] migration: use the free page reporting feature from balloon, (continued)