Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755815Ab0ARSVh (ORCPT ); Mon, 18 Jan 2010 13:21:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753933Ab0ARSVg (ORCPT ); Mon, 18 Jan 2010 13:21:36 -0500 Received: from mx1.redhat.com ([209.132.183.28]:5319 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753189Ab0ARSVf (ORCPT ); Mon, 18 Jan 2010 13:21:35 -0500 Message-ID: <4B54A68E.4050409@redhat.com> Date: Mon, 18 Jan 2010 13:21:02 -0500 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-3.fc11 Thunderbird/3.0 MIME-Version: 1.0 To: Mathieu Desnoyers CC: Arjan van de Ven , "H. Peter Anvin" , rostedt@goodmis.org, Jason Baron , linux-kernel@vger.kernel.org, mingo@elte.hu, tglx@linutronix.de, andi@firstfloor.org, roland@redhat.com, rth@redhat.com Subject: Re: [RFC PATCH 2/8] jump label v4 - x86: Introduce generic jump patching without stop_machine References: <1263483139.28171.3857.camel@gandalf.stny.rr.com> <4B4F3A1A.2030906@zytor.com> <20100117185539.GF9008@Krystal> <20100117111608.35a98ee2@infradead.org> <4B548562.6030008@redhat.com> <20100118083129.675edb83@infradead.org> <20100118165443.GB29764@Krystal> In-Reply-To: <20100118165443.GB29764@Krystal> X-Enigmail-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1248 Lines: 42 Mathieu Desnoyers wrote: > * Arjan van de Ven (arjan@infradead.org) wrote: >> On Mon, 18 Jan 2010 10:59:30 -0500 >> Masami Hiramatsu wrote: >> >>> Yeah, so in the latest patch, I updated it to use int3 even if >>> len == 1. :-) >>> >> >> >> int3 is not making a difference for your case; there is no guarantee >> that the other processor even sees the "int3 inbetween state" at all; >> if it's not safe without int3 then it won't be safe with int3 either. > > What Masami means is that he updated his patch to use the int3+IPI > broadcast scheme. Right. > > Therefore, the CPUs not seeing the int3 inbetween state will be forced > to issue a serializing instruction while the int3 is in place anyway. By the way, in kprobes, we just use a text_poke() to put int3. I assume that we'd better send IPI afterward, wouldn't it? Thank you, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division e-mail: mhiramat@redhat.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/