From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Anthony Liguori <aliguori@us.ibm.com>,
Glauber Costa <glommer@gmail.com>,
Chris Wright <chrisw@redhat.com>,
Uri Lublin <uri.lublin@qumranet.com>,
kvm@vger.kernel.org
Subject: Re: [Qemu-devel] [PATCH 3/10] Add bdrv_flush_all()
Date: Wed, 10 Sep 2008 17:37:17 +0100 [thread overview]
Message-ID: <200809101737.18560.paul@codesourcery.com> (raw)
In-Reply-To: <48C7E579.5040702@us.ibm.com>
> I'm actually liking bdrv_flush_all() less and less. If there are any
> outstanding IO requests, it will increase the down time associated with
> live migration. I think we definitely need to add a live save handler
> that waits until there are no outstanding IO requests to converge. I'm
> concerned though that it's not totally unreasonable to expect a guest to
> always have an IO request in flight. That leads me to think that maybe
> we should be cancelling outstanding requests, and somehow saving their
> state?
That's not possible with the current code because the IO callbacks
(particularly when you start involving the SCSI layer) are generated
dynamically.
Paul
WARNING: multiple messages have this Message-ID (diff)
From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Chris Wright <chrisw@redhat.com>,
Glauber Costa <glommer@gmail.com>,
Anthony Liguori <aliguori@us.ibm.com>,
kvm@vger.kernel.org, Uri Lublin <uri.lublin@qumranet.com>
Subject: Re: [Qemu-devel] [PATCH 3/10] Add bdrv_flush_all()
Date: Wed, 10 Sep 2008 17:37:17 +0100 [thread overview]
Message-ID: <200809101737.18560.paul@codesourcery.com> (raw)
In-Reply-To: <48C7E579.5040702@us.ibm.com>
> I'm actually liking bdrv_flush_all() less and less. If there are any
> outstanding IO requests, it will increase the down time associated with
> live migration. I think we definitely need to add a live save handler
> that waits until there are no outstanding IO requests to converge. I'm
> concerned though that it's not totally unreasonable to expect a guest to
> always have an IO request in flight. That leads me to think that maybe
> we should be cancelling outstanding requests, and somehow saving their
> state?
That's not possible with the current code because the IO callbacks
(particularly when you start involving the SCSI layer) are generated
dynamically.
Paul
next prev parent reply other threads:[~2008-09-10 16:37 UTC|newest]
Thread overview: 95+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-09 19:49 [PATCH 0/10] Live migration for QEMU Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-09 19:49 ` [PATCH 1/10] Refactor QEMUFile for live migration Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-10 13:25 ` Chris Lalancette
2008-09-10 14:38 ` Glauber Costa
2008-09-10 14:38 ` [Qemu-devel] " Glauber Costa
2008-09-10 15:05 ` Avi Kivity
2008-09-10 15:05 ` Avi Kivity
2008-09-10 15:16 ` Anthony Liguori
2008-09-10 15:16 ` [Qemu-devel] " Anthony Liguori
2008-09-12 15:40 ` [Qemu-devel] " Blue Swirl
2008-09-09 19:49 ` [PATCH 2/10] Allow the monitor to be suspended during non-blocking op Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-10 6:52 ` Avi Kivity
2008-09-10 10:05 ` Daniel P. Berrange
2008-09-10 10:05 ` Daniel P. Berrange
2008-09-10 11:11 ` Avi Kivity
2008-09-10 11:11 ` Avi Kivity
2008-09-10 11:14 ` Daniel P. Berrange
2008-09-10 11:14 ` Daniel P. Berrange
2008-09-10 15:36 ` Avi Kivity
2008-09-10 15:36 ` Avi Kivity
2008-09-10 15:40 ` Anthony Liguori
2008-09-10 15:40 ` Anthony Liguori
2008-09-10 15:58 ` Jamie Lokier
2008-09-10 15:58 ` Jamie Lokier
2008-09-11 10:16 ` Avi Kivity
2008-09-11 11:59 ` Jamie Lokier
2008-09-10 13:07 ` Anthony Liguori
2008-09-10 13:07 ` Anthony Liguori
2008-09-10 13:26 ` Chris Lalancette
2008-09-10 13:26 ` Chris Lalancette
2008-09-10 10:01 ` Daniel P. Berrange
2008-09-10 13:11 ` Anthony Liguori
2008-09-10 13:11 ` Anthony Liguori
2008-09-09 19:49 ` [PATCH 3/10] Add bdrv_flush_all() Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-10 13:26 ` Chris Lalancette
2008-09-10 13:26 ` [Qemu-devel] " Chris Lalancette
2008-09-10 14:46 ` Glauber Costa
2008-09-10 15:19 ` Anthony Liguori
2008-09-10 15:19 ` Anthony Liguori
2008-09-10 15:32 ` Glauber Costa
2008-09-10 15:32 ` Glauber Costa
2008-09-10 15:39 ` Avi Kivity
2008-09-10 15:39 ` Avi Kivity
2008-09-10 16:37 ` Paul Brook [this message]
2008-09-10 16:37 ` Paul Brook
2008-09-12 15:43 ` Blue Swirl
2008-09-09 19:49 ` [PATCH 4/10] Add dirty tracking for live migration Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-10 14:52 ` Glauber Costa
2008-09-10 14:56 ` Anthony Liguori
2008-09-10 14:56 ` Anthony Liguori
2008-09-10 15:01 ` Glauber Costa
2008-09-10 15:01 ` Glauber Costa
2008-09-09 19:49 ` [PATCH 5/10] Add network announce function Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-10 13:27 ` Chris Lalancette
2008-09-10 13:54 ` Anthony Liguori
2008-09-10 13:54 ` Anthony Liguori
2008-09-10 14:00 ` Avi Kivity
2008-09-09 19:49 ` [PATCH 6/10] Introduce v3 of savevm protocol Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-10 7:09 ` Avi Kivity
2008-09-09 19:49 ` [PATCH 7/10] Switch the memory savevm handler to be "live" Anthony Liguori
2008-09-09 19:49 ` [Qemu-devel] " Anthony Liguori
2008-09-09 22:25 ` Jamie Lokier
2008-09-09 22:49 ` Anthony Liguori
2008-09-09 22:49 ` Anthony Liguori
2008-09-10 7:17 ` Avi Kivity
2008-09-10 13:10 ` Anthony Liguori
2008-09-10 13:10 ` Anthony Liguori
2008-09-09 19:50 ` [PATCH 8/10] Introduce a buffered QEMUFile wrapper Anthony Liguori
2008-09-09 19:50 ` [Qemu-devel] " Anthony Liguori
2008-09-12 15:16 ` Blue Swirl
2008-09-09 19:50 ` [PATCH 9/10] Introduce the UI components for live migration Anthony Liguori
2008-09-09 19:50 ` [Qemu-devel] " Anthony Liguori
2008-09-09 19:50 ` [PATCH 10/10] TCP based " Anthony Liguori
2008-09-09 19:50 ` [Qemu-devel] " Anthony Liguori
2008-09-10 16:46 ` Blue Swirl
2008-09-10 16:51 ` Anthony Liguori
2008-09-10 16:51 ` Anthony Liguori
2008-09-11 12:13 ` [Qemu-devel] [PATCH 0/10] Live migration for QEMU Atsushi SAKAI
2008-09-11 13:06 ` Anthony Liguori
2008-09-11 13:30 ` Jamie Lokier
2008-09-11 14:12 ` Anthony Liguori
2008-09-11 14:12 ` Anthony Liguori
2008-09-11 15:32 ` Avi Kivity
2008-09-11 15:32 ` Avi Kivity
2008-09-11 16:22 ` Anthony Liguori
2008-09-11 16:22 ` Anthony Liguori
2008-09-11 16:32 ` Avi Kivity
2008-09-11 16:32 ` Avi Kivity
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