From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756247Ab2BCUKi (ORCPT <rfc822;w@1wt.eu>);
	Fri, 3 Feb 2012 15:10:38 -0500
Received: from hrndva-omtalb.mail.rr.com ([71.74.56.125]:40776 "EHLO
	hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1755938Ab2BCUKf (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Fri, 3 Feb 2012 15:10:35 -0500
X-Authority-Analysis: v=2.0 cv=HeuWv148 c=1 sm=0 a=ZycB6UtQUfgMyuk2+PxD7w==:17 a=JWdsGIDjgj4A:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=ybhEY36hXgcA9dyJ_jIA:9 a=PUjeQqilurYA:10 a=5sSclSeBaXwgqdo3:21 a=AZXu_MlKgeb8xAl5:21 a=ZycB6UtQUfgMyuk2+PxD7w==:117
X-Cloudmark-Score: 0
X-Originating-IP: 74.67.80.29
Message-ID: <1328299833.5882.211.camel@gandalf.stny.rr.com>
Subject: Re: [PATCH RT 2/2 v4] preempt-rt/x86: Delay calling signals in int3
From: Steven Rostedt <rostedt@goodmis.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org,
        linux-rt-users <linux-rt-users@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>, Carsten Emde <C.Emde@osadl.org>,
        John Kacur <jkacur@redhat.com>,
        Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
        Ingo Molnar <mingo@elte.hu>, Andrew Morton <akpm@linux-foundation.org>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Alexander van Heukelum <heukelum@fastmail.fm>,
        Andi Kleen <ak@linux.intel.com>, Clark Williams <williams@redhat.com>,
        Luis Goncalves <lgoncalv@redhat.com>, stable-rt@vger.kernel.org
Date: Fri, 03 Feb 2012 15:10:33 -0500
In-Reply-To: <20120203184016.GA10413@redhat.com>
References: <20120203182853.547078531@goodmis.org>
	 <20120203183041.427463295@goodmis.org> <20120203184016.GA10413@redhat.com>
Content-Type: text/plain; charset="ISO-8859-15"
X-Mailer: Evolution 3.2.2-1 
Content-Transfer-Encoding: 7bit
Mime-Version: 1.0
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, 2012-02-03 at 19:40 +0100, Oleg Nesterov wrote:

> Stupid question. Do we really need to send the signal from here?

If we can do it correctly elsewhere, I'm fine with that too :-)

> 
> Why force_sig(rt => T) can't set TIF_NOTIFY_RESUME instead? Then
> we can change do_notify_resume() to check TIF_FORCE_SIG_TRAP. And
> perhaps we can even avoid the new TIF_FORCE_SIG_TRAP, we could
> check task->stored_info_set.

You know the signal code much better than I do. If that works, I'm all
for that too. I really don't like the entry_64 solution, but it was what
I knew would work.

> 
> In fact I feel this can be simplified even more, but I am not sure.

My strengths are in the entry_64.S code, not the signal code, so I fixed
it the best way that I felt. This does not imply my fix is the best. If
we can solve this in a clean way using the existing signal
infrastructure, I'm all for that.

-- Steve