From: Olaf Hering <olaf@aepfle.de>
To: Andres Lagar-Cavilla <andres@lagarcavilla.org>
Cc: keir.xen@gmail.com, xen-devel@lists.xensource.com
Subject: Re: Need help with fixing the Xen waitqueue feature
Date: Wed, 9 Nov 2011 23:11:49 +0100 [thread overview]
Message-ID: <20111109221148.GA17166@aepfle.de> (raw)
In-Reply-To: <0bb01a4d216a68c4ae8441b037927f61.squirrel@webmail.lagarcavilla.org>
On Wed, Nov 09, Andres Lagar-Cavilla wrote:
> After a bit of thinking, things are far more complicated. I don't think
> this is a "race." If the pager removed a page that later gets scheduled by
> the guest OS for IO, qemu will want to foreign-map that. With the
> hypervisor returning ENOENT, the foreign map will fail, and there goes
> qemu.
The tools are supposed to catch ENOENT and try again.
linux_privcmd_map_foreign_bulk() does that. linux_gnttab_grant_map()
appears to do that as well. What code path uses qemu that leads to a
crash?
> I guess qemu/migrate/libxc could retry until the pager is done and the
> mapping succeeds. It will be delicate. It won't work for pv backends. It
> will flood the mem_event ring.
There will no flood, only one request is sent per gfn in
p2m_mem_paging_populate().
Olaf
next prev parent reply other threads:[~2011-11-09 22:11 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111108224414.83985CF73A@homiemail-mx7.g.dreamhost.com>
2011-11-09 3:52 ` Need help with fixing the Xen waitqueue feature Andres Lagar-Cavilla
2011-11-09 7:09 ` Olaf Hering
2011-11-09 21:21 ` Andres Lagar-Cavilla
2011-11-22 14:34 ` George Dunlap
2011-11-09 21:30 ` Andres Lagar-Cavilla
2011-11-09 22:11 ` Olaf Hering [this message]
2011-11-10 4:29 ` Andres Lagar-Cavilla
2011-11-10 9:20 ` Jan Beulich
2011-11-10 13:57 ` Andres Lagar-Cavilla
2011-11-10 15:32 ` Konrad Rzeszutek Wilk
2011-11-10 9:26 ` Keir Fraser
2011-11-10 10:18 ` Olaf Hering
2011-11-10 12:05 ` Olaf Hering
[not found] <20111122150755.GA18727@aepfle.de>
2011-11-22 15:40 ` Keir Fraser
2011-11-22 15:54 ` Keir Fraser
2011-11-22 17:36 ` Olaf Hering
2011-11-22 17:42 ` Keir Fraser
2011-11-22 18:04 ` Olaf Hering
2011-11-22 21:15 ` Olaf Hering
2011-11-22 21:53 ` Keir Fraser
2011-11-23 17:00 ` Olaf Hering
2011-11-23 17:16 ` Keir Fraser
2011-11-23 18:06 ` Olaf Hering
2011-11-23 18:23 ` Keir Fraser
2011-11-23 18:18 ` Keir Fraser
2011-11-23 18:31 ` Olaf Hering
2011-11-23 19:21 ` Keir Fraser
2011-11-23 21:03 ` Keir Fraser
2011-11-23 22:30 ` Olaf Hering
2011-11-23 23:12 ` Keir Fraser
2011-11-24 10:00 ` Olaf Hering
2011-11-25 12:56 ` Olaf Hering
2011-11-25 18:26 ` Olaf Hering
2011-11-25 19:35 ` Keir Fraser
2011-11-24 9:15 ` Jan Beulich
2011-11-24 9:51 ` Keir Fraser
2011-11-24 9:58 ` Keir Fraser
[not found] <20111108214540.EAEBB72C4A1@homiemail-mx8.g.dreamhost.com>
2011-11-09 3:37 ` Andres Lagar-Cavilla
2011-11-09 7:02 ` Olaf Hering
2011-11-08 21:20 Olaf Hering
2011-11-08 22:05 ` Keir Fraser
2011-11-08 22:20 ` Olaf Hering
2011-11-08 22:54 ` Keir Fraser
2011-11-11 22:56 ` Olaf Hering
2011-11-12 7:00 ` Keir Fraser
2011-11-22 11:40 ` Olaf Hering
2011-11-22 13:04 ` Keir Fraser
2011-11-22 13:54 ` Olaf Hering
2011-11-22 14:24 ` Keir Fraser
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