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Re: [Qemu-block] [Qemu-devel] [PATCH 1/3] block: count bdrv_co_rw_vmstat
From: |
Eric Blake |
Subject: |
Re: [Qemu-block] [Qemu-devel] [PATCH 1/3] block: count bdrv_co_rw_vmstate() requests |
Date: |
Wed, 17 May 2017 15:09:51 -0500 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 |
On 05/17/2017 12:09 PM, Stefan Hajnoczi wrote:
> Call bdrv_inc/dec_in_flight() for vmstate reads/writes. This seems
> unnecessary at first glance because vmstate reads/writes are done
> synchronously while the guest is stopped. But we need the bdrv_wakeup()
> in bdrv_dec_in_flight() so the main loop sees request completion.
> Besides, it's cleaner to count vmstate reads/writes like ordinary
> read/write requests.
>
> The bdrv_wakeup() partially fixes a 'savevm' hang with -object iothread.
>
> Signed-off-by: Stefan Hajnoczi <address@hidden>
> ---
> block/io.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
Reviewed-by: Eric Blake <address@hidden>
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3266
Virtualization: qemu.org | libvirt.org
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[Qemu-block] [PATCH 3/3] migration: avoid recursive AioContext locking in save_vmstate(), Stefan Hajnoczi, 2017/05/17