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Re: [Xen-devel] [PATCH] serialize suspend-resume process

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] serialize suspend-resume process
From: BVK Chaitanya <bayapuneni_chaitanya@xxxxxxxxxxxx>
Date: Thu, 31 Jul 2008 17:27:24 +0530
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Keir Fraser wrote:
On 31/7/08 12:09, "BVK Chaitanya" <bayapuneni_chaitanya@xxxxxxxxxxxx> wrote:

Below patch makes suspend-resume process serialized.

It's already supposed to be serialised, and there's a loop in xen_suspend()
to deal with up to one queued suspend request. Your patch may deal with an
arbitrary number of queued suspend requests, but a sane dom0 control stack
should never issue more than one suspend request in a suspend-resume cycle.


Yes, but there must be a way for dom0 to know that suspend-resume cycle is completed. Currently dom0 only gets suspend completed notification -- as part of shutdown hypercall -- but no resume (xenbus_suspend_cancel) completed notification.

If dom0 issues second suspend request before resume is completed a _new_ kthread is started and will proceed with xen_suspend in parallel. I saw this hitting BUG_ON in netfront_accelerator_add_watch.

Am i missing anything?


regards,
--
bvk-chaitanya



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