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From: Kevin Wolf <kwolf@redhat.com>
To: Zhang Haoyu <zhanghy@sangfor.com>
Cc: qemu-devel <qemu-devel@nongnu.org>,
	Stefan Hajnoczi <stefanha@redhat.com>,
	Max Reitz <mreitz@redhat.com>
Subject: Re: [Qemu-devel] [question] savevm/delvm: Is it neccesary to perform bdrv_drain_all before savevm and delvm?
Date: Mon, 20 Oct 2014 15:59:55 +0200	[thread overview]
Message-ID: <20141020135955.GL3585@noname.redhat.com> (raw)
In-Reply-To: <201410202148499451733@sangfor.com>

Am 20.10.2014 um 15:48 hat Zhang Haoyu geschrieben:
> Hi,
> 
> I noticed that bdrv_drain_all is performed in load_vmstate before bdrv_snapshot_goto,
> and bdrv_drain_all is performed in qmp_transaction before internal_snapshot_prepare,
> so is it also neccesary to perform bdrv_drain_all in savevm and delvm?

Definitely yes for savevm. do_savevm() calls it indirectly via
vm_stop(), so that part looks okay.

delvm doesn't affect the currently running VM, and therefore doesn't
interfere with guest requests that are in flight. So I think that a
bdrv_drain_all() isn't needed there.

Kevin

  reply	other threads:[~2014-10-20 14:00 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-20 13:48 [Qemu-devel] [question] savevm/delvm: Is it neccesary to perform bdrv_drain_all before savevm and delvm? Zhang Haoyu
2014-10-20 13:59 ` Kevin Wolf [this message]
2014-10-20 15:09   ` [Qemu-devel] [question] savevm/delvm: Is it necessary " Zhang Haoyu
2014-10-20 16:07     ` Kevin Wolf
2014-10-21  1:13       ` Zhang Haoyu
2014-10-21  7:19         ` Kevin Wolf
2014-10-21  7:51           ` [Qemu-devel] [question] savevm/delvm: Is it necessary to performbdrv_drain_all " Zhang Haoyu

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