From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id 2EB286B00CE for ; Mon, 18 Oct 2010 22:54:15 -0400 (EDT) Received: from m5.gw.fujitsu.co.jp ([10.0.50.75]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o9J2sAxg017920 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 19 Oct 2010 11:54:11 +0900 Received: from smail (m5 [127.0.0.1]) by outgoing.m5.gw.fujitsu.co.jp (Postfix) with ESMTP id 3624A45DE58 for ; Tue, 19 Oct 2010 11:54:10 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (s5.gw.fujitsu.co.jp [10.0.50.95]) by m5.gw.fujitsu.co.jp (Postfix) with ESMTP id D775945DE57 for ; Tue, 19 Oct 2010 11:54:09 +0900 (JST) Received: from s5.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 5B528E38003 for ; Tue, 19 Oct 2010 11:54:09 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.249.87.104]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id E1C4CE38001 for ; Tue, 19 Oct 2010 11:54:08 +0900 (JST) From: KOSAKI Motohiro Subject: Re: Deadlock possibly caused by too_many_isolated. In-Reply-To: References: <20101019105257.A1C6.A69D9226@jp.fujitsu.com> Message-Id: <20101019113316.A1CF.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 19 Oct 2010 11:54:08 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , Neil Brown , Wu Fengguang , Rik van Riel , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "Li, Shaohua" List-ID: > >> > Can you please elaborate your intention? Do you think Wu's approach is wrong? > >> > >> No. I think Wu's patch may work well. But I agree Andrew. > >> Couldn't we remove the too_many_isolated logic? If it is, we can solve > >> the problem simply. > >> But If we remove the logic, we will meet long time ago problem, again. > >> So my patch's intention is to prevent OOM and deadlock problem with > >> simple patch without adding new heuristic in too_many_isolated. > > > > But your patch is much false positive/negative chance because isolated pages timing > > and too_many_isolated_zone() call site are in far distance place. > > Yes. > How about the returning *did_some_progress can imply too_many_isolated > fail by using MSB or new variable? > Then, page_allocator can check it whether it causes read reclaim fail > or parallel reclaim. > The point is let's throttle without holding FS/IO lock. Wu's version sleep in shrink_inactive_list(). your version sleep in __alloc_pages_slowpath() by wait_iff_congested(). both don't release lock, I think. But, if alloc_pages() return fail if GFP_NOIO, we introduce another issue. -- 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