From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 33D6B6B00CE for ; Mon, 18 Oct 2010 22:37:06 -0400 (EDT) Received: from m6.gw.fujitsu.co.jp ([10.0.50.76]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o9J2b22i015610 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 19 Oct 2010 11:37:02 +0900 Received: from smail (m6 [127.0.0.1]) by outgoing.m6.gw.fujitsu.co.jp (Postfix) with ESMTP id 391AC45DE4E for ; Tue, 19 Oct 2010 11:37:02 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (s6.gw.fujitsu.co.jp [10.0.50.96]) by m6.gw.fujitsu.co.jp (Postfix) with ESMTP id F16CA45DE51 for ; Tue, 19 Oct 2010 11:37:01 +0900 (JST) Received: from s6.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id BE1C4E78002 for ; Tue, 19 Oct 2010 11:37:01 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s6.gw.fujitsu.co.jp (Postfix) with ESMTP id E6C02E38003 for ; Tue, 19 Oct 2010 11:37:00 +0900 (JST) From: KOSAKI Motohiro Subject: Re: Deadlock possibly caused by too_many_isolated. In-Reply-To: <20101019022451.GA8310@localhost> References: <20101018154137.90f5325f.akpm@linux-foundation.org> <20101019022451.GA8310@localhost> Message-Id: <20101019113558.A1D5.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 19 Oct 2010 11:37:00 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Wu Fengguang Cc: kosaki.motohiro@jp.fujitsu.com, Andrew Morton , Neil Brown , Rik van Riel , KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "Li, Shaohua" List-ID: > --- > Subject: vmscan: comment too_many_isolated() > From: Wu Fengguang > Date: Tue Oct 19 09:53:23 CST 2010 > > Comment "Why it's doing so" rather than "What it does" > as proposed by Andrew Morton. > > Signed-off-by: Wu Fengguang > --- > mm/vmscan.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > --- linux-next.orig/mm/vmscan.c 2010-10-19 09:29:44.000000000 +0800 > +++ linux-next/mm/vmscan.c 2010-10-19 10:21:41.000000000 +0800 > @@ -1142,7 +1142,11 @@ int isolate_lru_page(struct page *page) > } > > /* > - * Are there way too many processes in the direct reclaim path already? > + * A direct reclaimer may isolate SWAP_CLUSTER_MAX pages from the LRU list and > + * then get resheduled. When there are massive number of tasks doing page > + * allocation, such sleeping direct reclaimers may keep piling up on each CPU, > + * the LRU list will go small and be scanned faster than necessary, leading to > + * unnecessary swapping, thrashing and OOM. > */ > static int too_many_isolated(struct zone *zone, int file, > struct scan_control *sc) nice! Reviewed-by: KOSAKI Motohiro -- 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