From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from [140.186.70.92] (port=38713 helo=eggs.gnu.org)
	by lists.gnu.org with esmtp (Exim 4.43) id 1PjtcP-0000XX-NS
	for qemu-devel@nongnu.org; Mon, 31 Jan 2011 08:16:35 -0500
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <avi@redhat.com>) id 1PjtcO-0004Uu-KK
	for qemu-devel@nongnu.org; Mon, 31 Jan 2011 08:16:33 -0500
Received: from mx1.redhat.com ([209.132.183.28]:32873)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <avi@redhat.com>) id 1PjtcO-0004UX-9U
	for qemu-devel@nongnu.org; Mon, 31 Jan 2011 08:16:32 -0500
Message-ID: <4D46B62B.8020106@redhat.com>
Date: Mon, 31 Jan 2011 15:16:27 +0200
From: Avi Kivity <avi@redhat.com>
MIME-Version: 1.0
References: <cover.1296133797.git.jan.kiszka@siemens.com>
	<a7a2a912167d2ef699844c8c0e7b170b4d6f3fb1.1296133797.git.jan.kiszka@siemens.com>
	<4D468470.4060300@redhat.com> <4D469AAF.7090002@siemens.com>
In-Reply-To: <4D469AAF.7090002@siemens.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Subject: [Qemu-devel] Re: [PATCH 01/22] Prevent abortion on multiple VCPU
	kicks
List-Id: qemu-devel.nongnu.org
List-Unsubscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <http://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, "kvm@vger.kernel.org" <kvm@vger.kernel.org>

On 01/31/2011 01:19 PM, Jan Kiszka wrote:
> 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.
>

     } else if (!is_si_special(info)) {
         if (sig >= SIGRTMIN && info->si_code != SI_USER) {
             /*
              * Queue overflow, abort.  We may abort if the
              * signal was rt and sent by user using something
              * other than kill().
              */
             trace_signal_overflow_fail(sig, group, info);
             return -EAGAIN;
         }

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

Yes.

-- 
error compiling committee.c: too many arguments to function