Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754612AbZIWIsE (ORCPT ); Wed, 23 Sep 2009 04:48:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754491AbZIWIsD (ORCPT ); Wed, 23 Sep 2009 04:48:03 -0400 Received: from mail-bw0-f210.google.com ([209.85.218.210]:43924 "EHLO mail-bw0-f210.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754480AbZIWIsC (ORCPT ); Wed, 23 Sep 2009 04:48:02 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=hmUZ5sypONC/3HfSPBPNufrIHcLA286VdA02jugNumkT+FS7Ycxc1AGvkXT74uFqoN 3p3iO9XYQK1OwgrOav8ZjdWWsXu67+78EbUBnHoV4WvJmkMJNv6K0YFppo3cEtVi+yBD w+HoHR2D7gInf4KmLzthHkFbUzkukPMjUPkvg= MIME-Version: 1.0 In-Reply-To: References: <7863dc4c0909221409v7893bfd3o4b590d5951a233ba@mail.gmail.com> <20090922212453.GB6062@nowhere> <1253686585.7695.84.camel@twins> <20090923073253.GA18022@elte.hu> <20090923074028.GA3078@elte.hu> Date: Wed, 23 Sep 2009 12:48:04 +0400 Message-ID: Subject: Re: perf sched record hangs machine From: Cyrill Gorcunov To: Ingo Molnar Cc: Peter Zijlstra , Frederic Weisbecker , Chris Malley , linux-kernel@vger.kernel.org, Steven Rostedt Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2045 Lines: 59 On 9/23/09, Cyrill Gorcunov wrote: > On 9/23/09, Ingo Molnar wrote: >> >> * Ingo Molnar wrote: >> >>> >>> * Peter Zijlstra wrote: >>> >>> > .size default_send_IPI_self, .-default_send_IPI_self >>> > >>> > Which seems to suggest that cmove is in __prepare_ICR, but I'm not >>> > sure how that can cause a page-fault, as that function is rather >>> > pointer-less. >>> > >>> > Did it maybe delay evaluating apic->dest_logical that late, it appear >>> > to be the first usage of that argument? >>> > >>> > Ingo, any ideas? >>> >>> Yeah, the problem is: >>> >>> [ 0.042445] Local APIC not detected. Using dummy APIC emulation. >>> >>> we shouldnt be trying to program the lapic in that case - all ops >>> should be a NOP, including send-ipi-self. Cyrill? >> >> Cyrill, the right fix would be to define a: >> >> struct apic apic_none; >> >> with dummy functions injected. Set struct apic *apic to _that_, instead >> of apic_default. >> >> This means that if we manage to detect a local APIC, we will set it to >> apic_default (or some other driver) - but the bootup default will be 'no >> APIC'. >> > > May it wait till evening (i'll back from office and take a look)? > >> This is a lot cleaner and a lot less error-prone than the direct >> frobbing of the function pointers. >> >> Ingo >> > Btw, meanwhile Chris may try to pass lapic boot-option in attempt to reenable apic via msr registers. Also (iirc) i feel we may be hiding errors if complete noop apic would be used since i belive we need to check out under which condition a particular operation is called and when apic is disabled it's mean we're switched to UP mode and inter-cpu interrupts are under suspicion too. Will take a look during ~6 hours ;) -- 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/