From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx120.postini.com [74.125.245.120]) by kanga.kvack.org (Postfix) with SMTP id C2E5E6B005D for ; Thu, 20 Dec 2012 19:36:53 -0500 (EST) Date: Fri, 21 Dec 2012 01:36:49 +0100 From: Petr Holasek Subject: Re: [PATCH] ksm: make rmap walks more scalable Message-ID: <20121221003648.GA9649@thinkpad-work.redhat.com> References: <50D387FD.4020008@oracle.com> <50D3947F.2060503@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <50D3947F.2060503@oracle.com> Sender: owner-linux-mm@kvack.org List-ID: To: Sasha Levin Cc: Hugh Dickins , Mel Gorman , Linus Torvalds , Andrew Morton , Ingo Molnar , linux-kernel@vger.kernel.org, linux-mm@kvack.org On Thu, 20 Dec 2012, Sasha Levin wrote: > On 12/20/2012 05:37 PM, Hugh Dickins wrote: > > On Thu, 20 Dec 2012, Sasha Levin wrote: > >> On 12/19/2012 08:44 PM, Hugh Dickins wrote: > >>> The rmap walks in ksm.c are like those in rmap.c: > >>> they can safely be done with anon_vma_lock_read(). > >>> > >>> Signed-off-by: Hugh Dickins > >>> --- > >> > >> Hi Hugh, > >> > >> This patch didn't fix the ksm oopses I'm seeing. > > > > I wouldn't expect it to (and should certainly have mentioned oopses > > in the commit message if I'd intended): this patch was merely an > > optimization/clarification of a commit gone in for 3.8-rc1. > > > > Understandable misunderstanding: you took my Cc too seriously, > > I just thought I'd better keep Petr in the loop on current changes > > to ksm.c, and foolishly kept you in too ;) > > > > Your oopses are on linux-next, which as of 20121220 still had Petr's > > nice but buggy NUMA KSM patch in: it should go away when Stephen gets > > a fresh mm update from Andrew, then reappear once his v6 goes into mm. > > > > To stop these oopses in get_mergeable_page (inlined in > > unstable_tree_search_insert) you need the patch I showed on > > Tuesday, which I hope he'll merge in for his v6. That doesn't fix > > all of the problems, but hopefully all that you'll encounter before > > I've devised a fix for the separate stale stable_nodes issue. > > My bad! I thought that this is the finalized version of the patch from > Tuesday and was surprised when the oops was still there :) > > fwiw I'll use this to report that I'm not seeing any unexpected behaviour > with this patch applied. > > > Thanks, > Sasha > Hugh, big thanks for your Tuesday fix, I am not able to reproduce reported oops any more. I will continue with testing overnight and submit v6 version tomorrow if there won't be any problem. Should I also add [PATCH] ksm: make rmap walks more scalable into v6 or can I rely on it? thanks, Petr H -- 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