From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 01 Nov 2011 17:00:01 +0100 (CET) Received: from mail-gx0-f177.google.com ([209.85.161.177]:45760 "EHLO mail-gx0-f177.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1901351Ab1KAP75 (ORCPT ); Tue, 1 Nov 2011 16:59:57 +0100 Received: by ggnk3 with SMTP id k3so8122400ggn.36 for ; Tue, 01 Nov 2011 08:59:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=niMISTMFnh5R4oEAU5DX47GEf+r8XSa/lL3yalhTxtQ=; b=u0Ly0DQZohCzoFNid1UHfHcjYoP9R1dfKTyac4Ud0BuSCfRk66nH1H1LSYppTgEd05 UObGiXrYO9+f8FK9Xk7NCYtVhOP20ddBWaeIbKOQZ+/Z5Cpxd2Vi4eUDLJ0pknc84cAu hG+8IbZTeldOB4p4HDfglxGmm1ILgUhNSvZm0= Received: by 10.236.195.36 with SMTP id o24mr102917yhn.57.1320163191348; Tue, 01 Nov 2011 08:59:51 -0700 (PDT) Received: from google.com (tejun.mtv.corp.google.com [172.18.96.198]) by mx.google.com with ESMTPS id o64sm8104639yhk.3.2011.11.01.08.59.47 (version=SSLv3 cipher=OTHER); Tue, 01 Nov 2011 08:59:49 -0700 (PDT) Date: Tue, 1 Nov 2011 08:59:45 -0700 From: Tejun Heo To: Oleg Nesterov Cc: trisha yad , linux-mm , Russell King - ARM Linux , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, rientjes@google.com, Andrew Morton , Konstantin Khlebnikov , KOSAKI Motohiro , "Rafael J. Wysocki" , Rusty Russell Subject: Re: Issue with core dump Message-ID: <20111101155945.GQ18855@google.com> References: <20111101152320.GA30466@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111101152320.GA30466@redhat.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-archive-position: 31339 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: htejun@gmail.com Precedence: bulk X-list: linux-mips Return-Path: X-Keywords: X-UID: 488 Hello, On Tue, Nov 01, 2011 at 04:23:20PM +0100, Oleg Nesterov wrote: > Whatever we do, we can't "stop" other threads at the time when > thread 'a' traps. All we can do is to try to shrink the window. Yeah, "at the time" can't even be defined preciesly. Order of operation isn't clearly defined in absence of synchronization constructs. In the described example, there's unspecified amount of time (or cycles rather) between the load of the global variable and the thread faulting. Anything could have happened inbetween no matter how immediate core dump was. As long as we're reasonably immediate, which I think we already are, I don't think there's much which needs to be changed. Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id 424796B0069 for ; Tue, 1 Nov 2011 11:59:53 -0400 (EDT) Received: by ywa17 with SMTP id 17so9423307ywa.14 for ; Tue, 01 Nov 2011 08:59:51 -0700 (PDT) Date: Tue, 1 Nov 2011 08:59:45 -0700 From: Tejun Heo Subject: Re: Issue with core dump Message-ID: <20111101155945.GQ18855@google.com> References: <20111101152320.GA30466@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111101152320.GA30466@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov Cc: trisha yad , linux-mm , Russell King - ARM Linux , linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, kamezawa.hiroyu@jp.fujitsu.com, mhocko@suse.cz, rientjes@google.com, Andrew Morton , Konstantin Khlebnikov , KOSAKI Motohiro , "Rafael J. Wysocki" , Rusty Russell Hello, On Tue, Nov 01, 2011 at 04:23:20PM +0100, Oleg Nesterov wrote: > Whatever we do, we can't "stop" other threads at the time when > thread 'a' traps. All we can do is to try to shrink the window. Yeah, "at the time" can't even be defined preciesly. Order of operation isn't clearly defined in absence of synchronization constructs. In the described example, there's unspecified amount of time (or cycles rather) between the load of the global variable and the thread faulting. Anything could have happened inbetween no matter how immediate core dump was. As long as we're reasonably immediate, which I think we already are, I don't think there's much which needs to be changed. Thanks. -- tejun -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org