Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753862Ab1CURVj (ORCPT ); Mon, 21 Mar 2011 13:21:39 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:35266 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751539Ab1CURVh (ORCPT ); Mon, 21 Mar 2011 13:21:37 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=qwfzrtPnWb6VxcWZV671WMAZYOvL7DCXmvUSXA6JQStXNAX500q8irhMl/87Hb8PFD mWxFx5VgIOSe/biqn85rMwRhGTiizFtaNURgCuDgoOY6uYeDfouGsZEva3U1nZ+2mTxC /hvc/FmbRmjUJfVlYkpa1r0WgMVEu74+8FPzc= Message-ID: <4D87888D.4050400@gmail.com> Date: Mon, 21 Mar 2011 20:19:09 +0300 From: Cyrill Gorcunov User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.14) Gecko/20110223 Thunderbird/3.1.8 MIME-Version: 1.0 To: Jack Steiner CC: Ingo Molnar , Don Zickus , tglx@linutronix.de, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra Subject: Re: [PATCH] x86, UV: Fix NMI handler for UV platforms References: <20110321160135.GA31562@sgi.com> <20110321161425.GC23614@elte.hu> <4D877C4B.9090602@gmail.com> <4D878042.9080708@gmail.com> <4D878445.6090709@gmail.com> <20110321170832.GC12718@sgi.com> In-Reply-To: <20110321170832.GC12718@sgi.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2021 Lines: 53 On 03/21/2011 08:08 PM, Jack Steiner wrote: > On Mon, Mar 21, 2011 at 08:00:53PM +0300, Cyrill Gorcunov wrote: >> On 03/21/2011 07:43 PM, Cyrill Gorcunov wrote: >> ... >>> >>> I think Jack might need to setup priority for his notifier, like >>> >>> static struct notifier_block uv_dump_stack_nmi_nb = { >>> .notifier_call = uv_handle_nmi, >>> .priority = NMI_LOCAL_HIGH_PRIOR+1, >>> }; >>> >>> so it would be called before perf nmi. Don, am I right? >>> >>> Since for perf nmis we do have >>> >>> static __read_mostly struct notifier_block perf_event_nmi_notifier = { >>> .notifier_call = perf_event_nmi_handler, >>> .next = NULL, >>> .priority = NMI_LOCAL_LOW_PRIOR, >>> }; >>> >> >> I must admit I've missed the fact that Jack has tried NMIs priorities, right? >> x86_platform_ops seems to be a cleaner indeed (btw I think p4 pmu kgdb issue >> is exactly the same problem) but same time this might end up in over-swelled >> ideas behind this small code snippet. Dunno. Probably we need some per-cpu >> system status for nmi reasons other than unknown nmis... > > We use KDB internally, and yes, it has the same issue. The version of the > patch that uses KDB OR's the "handled" status for both KDB & the UV NMI handler. > If either KDB or the UV NMI handler returns "handled", the code in traps.c exits > after the call to the first die notifier. > > Not particularily pretty but I could not find a better way to do it. > > --- jack Another option might be to add pre-nmi notifier chain, which of course not much differ from platform ops but I guess platform ops stands mostly for one-shot events while chain might be more flexible. Ie I mean something like if (notify_pre_die(DIE_NMI, "nmi", regs, 0, 2, SIGINT) == NOTIFY_STOP) return; -- Cyrill -- 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/