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Date: Mon, 31 Jan 2011 12:19:11 +0100
From: Jan Kiszka <jan.kiszka@siemens.com>
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Subject: [Qemu-devel] Re: [PATCH 01/22] Prevent abortion on multiple VCPU
	kicks
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To: Avi Kivity <avi@redhat.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>

On 2011-01-31 10:44, Avi Kivity wrote:
> On 01/27/2011 03:09 PM, Jan Kiszka wrote:
>> If we call qemu_cpu_kick more than once before the target was able to
>> process the signal, pthread_kill will fail, and qemu will abort. Prevent
>> this by avoiding the redundant signal.
>>
> 
> Doesn't fit with the manual page (or with the idea that signals are 
> asynchronous):
> 
> NAME
>         pthread_kill - send a signal to a thread
> 
> 
> ...
> 
> ERRORS
>         ESRCH  No thread with the ID thread could be found.
> 
>         EINVAL An invalid signal was specified.
> 

Valid remark, but I was receiving EAGAIN for blocked RT signals. Don't
know if this is Linux-specific. A quick glance at the man pages did not
reveal if this is allowed or at least gray area.

However, even when selectively ignoring this, it's more efficient to
catch the redundant signaling in user space.

Jan

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