From: Keir Fraser <keir@xen.org>
To: Jan Beulich <JBeulich@suse.com>
Cc: Olaf Hering <olaf@aepfle.de>, xen-devel@lists.xensource.com
Subject: Re: Need help with fixing the Xen waitqueue feature
Date: Thu, 24 Nov 2011 09:51:27 +0000 [thread overview]
Message-ID: <CAF3C41F.34BDA%keir@xen.org> (raw)
In-Reply-To: <4ECE19400200007800062E4A@nat28.tlf.novell.com>
On 24/11/2011 09:15, "Jan Beulich" <JBeulich@suse.com> wrote:
>>
>> Attached three patches for you to try. They apply in sequence.
>> 00: A fixed version of "domain_crash on stack overflow"
>> 01: Reorders prepare_to_wait so that the vcpu will always be on the
>> waitqueue on exit (even if it has just been woken).
>> 02: Ensures the vcpu wakes up on the same cpu that it slept on.
>
> Didn't we (long ago) settle on not permitting new calls to
> domain_crash_synchronous()? Is it really impossible to just
> domain_crash() in any of the instances these add?
It's safe because you must be in a context that is safe to preempt. That's a
pre-condition for using a waitqueue. It's not safe to use domain_crash()
because the caller of wait_event() may not handle the exceptional return.
-- Keir
next prev parent reply other threads:[~2011-11-24 9:51 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20111122150755.GA18727@aepfle.de>
2011-11-22 15:40 ` Need help with fixing the Xen waitqueue feature 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 [this message]
2011-11-24 9:58 ` Keir Fraser
[not found] <20111108224414.83985CF73A@homiemail-mx7.g.dreamhost.com>
2011-11-09 3:52 ` 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
2011-11-10 4:29 ` Andres Lagar-Cavilla
2011-11-10 9:20 ` Jan Beulich
2011-11-10 9:26 ` Keir Fraser
2011-11-10 10:18 ` Olaf Hering
2011-11-10 12:05 ` Olaf Hering
[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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