From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx145.postini.com [74.125.245.145]) by kanga.kvack.org (Postfix) with SMTP id 3142B6B004D for ; Sun, 19 Feb 2012 19:33:40 -0500 (EST) Received: from m1.gw.fujitsu.co.jp (unknown [10.0.50.71]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id B18B83EE0B5 for ; Mon, 20 Feb 2012 09:33:38 +0900 (JST) Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 98DA745DE5F for ; Mon, 20 Feb 2012 09:33:38 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (s1.gw.fujitsu.co.jp [10.0.50.91]) by m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 7CFCF45DE59 for ; Mon, 20 Feb 2012 09:33:38 +0900 (JST) Received: from s1.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 667FCE08006 for ; Mon, 20 Feb 2012 09:33:38 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.240.81.145]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 1B6201DB804C for ; Mon, 20 Feb 2012 09:33:38 +0900 (JST) Date: Mon, 20 Feb 2012 09:32:17 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH RFC 00/15] mm: memory book keeping and lru_lock splitting Message-Id: <20120220093217.764e49f3.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20120215224221.22050.80605.stgit@zurg> <4F3C8B67.6090500@openvz.org> <4F3F46B7.40100@openvz.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Hugh Dickins Cc: Konstantin Khlebnikov , Ying Han , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" On Fri, 17 Feb 2012 23:14:01 -0800 (PST) Hugh Dickins wrote: > On Sat, 18 Feb 2012, Konstantin Khlebnikov wrote: > > Hugh Dickins wrote: > > > On Thu, 16 Feb 2012, Hugh Dickins wrote: > > > > > > > > Yours are not the only patches I was testing in that tree, I tried to > > > > gather several other series which I should be reviewing if I ever have > > > > time: Kamezawa-san's page cgroup diet 6, Xiao Guangrong's 4 prio_tree > > > > cleanups, your 3 radix_tree changes, your 6 shmem changes, your 4 memcg > > > > miscellaneous, and then your 15 books. > > > > > > > > The tree before your final 15 did well under pressure, until I tried to > > > > rmdir one of the cgroups afterwards: then it crashed nastily, I'll have > > > > to bisect into that, probably either Kamezawa's or your memcg changes. > > > > > > So far I haven't succeeded in reproducing that at all: it was real, > > > but obviously harder to get than I assumed - indeed, no good reason > > > to associate it with any of those patches, might even be in 3.3-rc. > > > > > > It did involve a NULL pointer dereference in mem_cgroup_page_lruvec(), > > > somewhere below compact_zone() - but repercussions were causing the > > > stacktrace to scroll offscreen, so I didn't get good details. > > > > There some stupid bugs in my v1 patchset, it shouldn't works at all. > > I did not expect that someone will try to use it. I sent it just to discuss. > > Yes, but as I said, that bug appeared before I put your patchset (the 15) on. > Hm, NULL pointer dereference in mem_cgroup_page_lruvec() via comaction tend to mean pc->mem_cgroup was NULL... IIUC, - compaction get pages from LRU list and isolate/migrate them. So, When pages on LRU were migrated by compact_zone(), pc->mem_cgroup never be NULL.. - All newly allocated pages for migration will be reset by mem_cgroup_reset_owner(). Hm, something unexpected happens.. Regards, -Kame -- 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