Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966522AbaFSXjE (ORCPT ); Thu, 19 Jun 2014 19:39:04 -0400 Received: from cantor2.suse.de ([195.135.220.15]:46916 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965603AbaFSXjC (ORCPT ); Thu, 19 Jun 2014 19:39:02 -0400 Date: Fri, 20 Jun 2014 01:38:59 +0200 (CEST) From: Jiri Kosina To: Steven Rostedt cc: linux-kernel@vger.kernel.org, Linus Torvalds , Ingo Molnar , Andrew Morton , Michal Hocko , Jan Kara , Frederic Weisbecker , Dave Anderson , Petr Mladek Subject: Re: [RFC][PATCH 0/3] x86/nmi: Print all cpu stacks from NMI safely In-Reply-To: <20140619193635.1949b469@gandalf.local.home> Message-ID: References: <20140619213329.478113470@goodmis.org> <20140619185810.4137e14b@gandalf.local.home> <20140619191923.1365850a@gandalf.local.home> <20140619193635.1949b469@gandalf.local.home> User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 19 Jun 2014, Steven Rostedt wrote: > > I don't think there is a need for a global stop_machine()-like > > synchronization here. The printing CPU will be sending IPI to the CPU N+1 > > only after it has finished printing CPU N stacktrace. > > So you plan on sending an IPI to a CPU then wait for it to acknowledge > that it is spinning, and then print out the data and then tell the CPU > it can stop spinning? Yes, that was exactly my idea. You have to be synchronized with the CPU receiving the NMI anyway in case you'd like to get its pt_regs and dump those as part of the dump. -- Jiri Kosina SUSE Labs -- 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/