Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756229AbYGLXZs (ORCPT ); Sat, 12 Jul 2008 19:25:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752370AbYGLXZk (ORCPT ); Sat, 12 Jul 2008 19:25:40 -0400 Received: from rv-out-0506.google.com ([209.85.198.239]:4095 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753451AbYGLXZj (ORCPT ); Sat, 12 Jul 2008 19:25:39 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version :content-type:content-transfer-encoding:content-disposition :references; b=MsX9Rd+TrGNGxynaY0rWcwcCQ3RqP1ek8AEC3co1zw769hBbI3TYUlGrvlcxdc1sYK vAaeqJkYbVOOADyCFqZxNy+FX7R25ix/BVNZnLGB8zs5SeJawrvPXiScn0thNaSKKGp9 ikcH/SmNsBpdIC9MhMfDTpx2r8A/o5XqsANk8= Message-ID: Date: Sun, 13 Jul 2008 01:25:39 +0200 From: "Dmitry Adamushko" To: "Linus Torvalds" Subject: Re: current linux-2.6.git: cpusets completely broken Cc: "Vegard Nossum" , "Paul Menage" , "Max Krasnyansky" , "Paul Jackson" , "Peter Zijlstra" , miaox@cn.fujitsu.com, rostedt@goodmis.org, "Thomas Gleixner" , "Ingo Molnar" , "Linux Kernel" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080712031736.GA3040@damson.getinternet.no> <19f34abd0807121600l653e28bfwb5cce2d880b7f2cd@mail.gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2228 Lines: 68 2008/7/13 Dmitry Adamushko : > 2008/7/13 Linus Torvalds : >> >>> (A little pet horse for the occasion: Testing can show the presence of >>> errors, but not their absence. But that's a different story.) >> >> Absolutely. Which is actually why I prefer my patch. I think it fixes - in >> general - the issue of CPU migration migrating tasks back to the CPU that >> we're taking down. >> >> The other patches seem to work around just the problem that _triggers_ the >> bug. They don't actually make it impossible to migrate to a CPU that is >> getting shut down - they just try to avoid the particular sequence that >> made it happen for you. > > Well, they try to make sched-domains consistent for all possible > cases, not just any particular case. So no, they don't allow a > possibility to leave tasks on a dead CPU (unless there is another > bug). > > With your patch (and a cpusets :: hotplug handler from the current > -git) sched-domains are still broken and they are used in a number of > places. So why keep them at all? > > I'm really surprised that Vegard says this "cpu_active_map" patch > alone fixes the problem. > > With your modifications of common_cpu_mem_hotplug_unplug() - yes No, not even with your modifications of common_mem_hotplug_unplug(). - if (phase == CPU_DYING || phase == CPU_DYING_FROZEN) + if (phase == CPU_DYING || phase == CPU_DYING_FROZEN || + phase == CPU_UP_PREPARE || phase == CPU_UP_PREPARE_FROZEN) return NOTIFY_DONE; You should have added "phase == CPU_DOWN_PREPARE || phase == CPU_DOWN_PREPARE_FROZEN" additionally. So I'm really surprised by Vegard's assertion :-) but > then it will work even without "cpu_active_map". > > (ok, unless I'm really blind at this late hour so please direct me to > the right way :-) > > >> >> Linus >> > > > -- > Best regards, > Dmitry Adamushko > -- Best regards, Dmitry Adamushko -- 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/