From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: alice wan <wanjia19870902@gmail.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: request of blkfront may disorder after migration without waiting in suspend phase of migration
Date: Tue, 12 Jul 2011 14:23:35 -0400 [thread overview]
Message-ID: <20110712182335.GA24828@dumpdata.com> (raw)
In-Reply-To: <CAKQ7UJnkTREkHw11_C46CTLzXwcgB_ADSGFONCMDKjPU=0nHKw@mail.gmail.com>
On Sun, Jul 10, 2011 at 12:36:06PM +0800, alice wan wrote:
> Hi konrad,
>
> I found the mainline linux 3.0-rc6 xen-blkfront driver doesn't implement
> suspend func. In my opinion, the blkfront should wait till responses of all
> the pending requests come back, then domu can be suspended,
I think you mean blkback. It should be the job of blkback to account for
all I/Os and make sure they have completed before migrating?
I did have a patch for the 2.6.32 to deal with this but I never was able
to reproduce this. Are you able to reproduce this? Can you give me
step by step instructions on how to do it?
> otherwise, after the migration, vm of target host will request from target
> host, meanwhile, the blkback of source host maybe do the pending requests
> until they's done.
>
> if migrate the vm with high io pressure, the requests of this vm may
> disorder.
>
> And i saw the gpl windows pv driver, blkfront will change its state and wait
> for blkback closing, after blkback closing, the pending requests definitely
> are done.
>
> More, i did some test with migration, while vm was running dd task, xm
> migrate -l . before it suspend, gdb tapdisk2. after migration, new vm
> started. then quit gdb, the pending request were written back to disk after
> new requests.
>
> above mentioned is just my opinion, i need your advice and confirmation or
> deny
>
> any help is appreciated.
>
>
> Regards
>
> wanjia
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel
next prev parent reply other threads:[~2011-07-12 18:23 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-10 4:36 request of blkfront may disorder after migration without waiting in suspend phase of migration alice wan
2011-07-10 8:26 ` Daniel Stodden
2011-07-12 18:23 ` Konrad Rzeszutek Wilk [this message]
2011-07-13 9:09 ` Ian Campbell
2011-07-14 2:03 ` Daniel Stodden
2011-07-13 10:57 ` alice wan
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