Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756531Ab3JHVrT (ORCPT ); Tue, 8 Oct 2013 17:47:19 -0400 Received: from relay1.sgi.com ([192.48.179.29]:56852 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753350Ab3JHVrS (ORCPT ); Tue, 8 Oct 2013 17:47:18 -0400 Date: Tue, 8 Oct 2013 16:47:17 -0500 From: Alex Thorlton To: "Kirill A. Shutemov" Cc: Ingo Molnar , Andrew Morton , Naoya Horiguchi , "Eric W . Biederman" , "Paul E . McKenney" , Al Viro , Andi Kleen , Andrea Arcangeli , Dave Hansen , Dave Jones , David Howells , Frederic Weisbecker , Johannes Weiner , Kees Cook , Mel Gorman , Michael Kerrisk , Oleg Nesterov , Peter Zijlstra , Rik van Riel , Robin Holt , Sedat Dilek , Srikar Dronamraju , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCHv4 00/10] split page table lock for PMD tables Message-ID: <20131008214717.GE25735@sgi.com> References: <1380287787-30252-1-git-send-email-kirill.shutemov@linux.intel.com> <20131004201213.GB32110@sgi.com> <20131004202602.2D389E0090@blue.fi.intel.com> <20131004203147.GE32110@sgi.com> <20131007094820.13A0CE0090@blue.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20131007094820.13A0CE0090@blue.fi.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2189 Lines: 58 On Mon, Oct 07, 2013 at 12:48:20PM +0300, Kirill A. Shutemov wrote: > Alex Thorlton wrote: > > > > Sorry for the delay on these results. I hit some strange issues with > > > > running thp_memscale on systems with either of the following > > > > combinations of configuration options set: > > > > > > > > [thp off] > > > > HUGETLBFS=y > > > > HUGETLB_PAGE=y > > > > NUMA_BALANCING=y > > > > NUMA_BALANCING_DEFAULT_ENABLED=y > > > > > > > > [thp on or off] > > > > HUGETLBFS=n > > > > HUGETLB_PAGE=n > > > > NUMA_BALANCING=y > > > > NUMA_BALANCING_DEFAULT_ENABLED=y > > > > > > > > I'm getting segfaults intermittently, as well as some weird RCU sched > > > > errors. This happens in vanilla 3.12-rc2, so it doesn't have anything > > > > to do with your patches, but I thought I'd let you know. There didn't > > > > used to be any issues with this test, so I think there's a subtle kernel > > > > bug here. That's, of course, an entirely separate issue though. > > > > > > I'll take a look next week, if nobody does it before. > > > > I'm starting a bisect now. Not sure how long it'll take, but I'll keep > > you posted. > > I don't see the issue. Could you share your kernel config? I put my kernel config up on ftp at: ftp://shell.sgi.com/collect/atconfig/config_bug I've been investigating the issue today and the smallest run I've seen the problem on was with 128 threads, so this might not be something that most people will hit. With the config I've shared here the problem appears to only be intermittent at 128 threads. It happened on every run of the test when I ran it with 512 threads. Just for something to compare to, here's a config that seems to behave just fine for any number of threads: ftp://shell.sgi.com/collect/atconfig/config_good It looks like this is a problem all the way back to the current 3.8 stable tree. I'm still working on tracing back to a kernel where this problem doesn't show up. - Alex -- 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/