From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f71.google.com (mail-oi0-f71.google.com [209.85.218.71]) by kanga.kvack.org (Postfix) with ESMTP id C68B56B0038 for ; Wed, 30 Nov 2016 14:22:02 -0500 (EST) Received: by mail-oi0-f71.google.com with SMTP id v84so375019420oie.0 for ; Wed, 30 Nov 2016 11:22:02 -0800 (PST) Received: from bh-25.webhostbox.net (bh-25.webhostbox.net. [208.91.199.152]) by mx.google.com with ESMTPS id t40si31812620ota.70.2016.11.30.11.22.01 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 30 Nov 2016 11:22:01 -0800 (PST) Date: Wed, 30 Nov 2016 11:21:59 -0800 From: Guenter Roeck Subject: Re: next: Commit 'mm: Prevent __alloc_pages_nodemask() RCU CPU stall ...' causing hang on sparc32 qemu Message-ID: <20161130192159.GB22216@roeck-us.net> References: <20161129212308.GA12447@roeck-us.net> <20161130012817.GH3924@linux.vnet.ibm.com> <20161130070212.GM3924@linux.vnet.ibm.com> <929f6b29-461a-6e94-fcfd-710c3da789e9@roeck-us.net> <20161130120333.GQ3924@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161130120333.GQ3924@linux.vnet.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: "Paul E. McKenney" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , sparclinux@vger.kernel.org, davem@davemloft.net On Wed, Nov 30, 2016 at 04:03:33AM -0800, Paul E. McKenney wrote: > On Wed, Nov 30, 2016 at 02:52:11AM -0800, Guenter Roeck wrote: > > On 11/29/2016 11:02 PM, Paul E. McKenney wrote: > > >On Tue, Nov 29, 2016 at 08:32:51PM -0800, Guenter Roeck wrote: > > >>On 11/29/2016 05:28 PM, Paul E. McKenney wrote: > > >>>On Tue, Nov 29, 2016 at 01:23:08PM -0800, Guenter Roeck wrote: > > >>>>Hi Paul, > > >>>> > > >>>>most of my qemu tests for sparc32 targets started to fail in next-20161129. > > >>>>The problem is only seen in SMP builds; non-SMP builds are fine. > > >>>>Bisect points to commit 2d66cccd73436 ("mm: Prevent __alloc_pages_nodemask() > > >>>>RCU CPU stall warnings"); reverting that commit fixes the problem. > > And I have dropped this patch. Michal Hocko showed me the error of > my ways with this patch. > :-) On another note, I still get RCU tracebacks in the s390 tests. BUG: sleeping function called from invalid context at mm/page_alloc.c:3775 That is caused by 'rcu: Maintain special bits at bottom of ->dynticks counter'; if I recall correctly we had discussed that earlier. Thanks, Guenter -- 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/ . Don't email: email@kvack.org