From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 21A986B00C2 for ; Mon, 23 Mar 2009 04:21:48 -0400 (EDT) Received: from m5.gw.fujitsu.co.jp ([10.0.50.75]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n2N9NcPx030173 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Mon, 23 Mar 2009 18:23:38 +0900 Received: from smail (m5 [127.0.0.1]) by outgoing.m5.gw.fujitsu.co.jp (Postfix) with ESMTP id 0A3E12AEA81 for ; Mon, 23 Mar 2009 18:23:38 +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 6C5AE1EF081 for ; Mon, 23 Mar 2009 18:23:37 +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 53795E08006 for ; Mon, 23 Mar 2009 18:23:37 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s5.gw.fujitsu.co.jp (Postfix) with ESMTP id 033AE1DB8043 for ; Mon, 23 Mar 2009 18:23:37 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [patch 3/3] mm: keep pages from unevictable mappings off the LRU lists In-Reply-To: <20090323175507.6A18.A69D9226@jp.fujitsu.com> References: <20090323084254.GA1685@cmpxchg.org> <20090323175507.6A18.A69D9226@jp.fujitsu.com> Message-Id: <20090323182039.6A1B.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Mon, 23 Mar 2009 18:23:36 +0900 (JST) Sender: owner-linux-mm@kvack.org To: KOSAKI Motohiro Cc: Johannes Weiner , Minchan Kim , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, David Howells , Nick Piggin , Rik van Riel , Peter Zijlstra , Lee Schermerhorn List-ID: > > > this is the just reason why current code don't call add_page_to_unevictable_list(). > > > add_page_to_unevictable_list() don't use pagevec. it is needed for avoiding race. > > > > > > then, if readahead path (i.e. add_to_page_cache_lru()) use add_page_to_unevictable_list(), > > > it can cause zone->lru_lock contention storm. > > > > How is it different then shrink_page_list()? If readahead put a > > contiguous chunk of unevictable pages to the file lru, then > > shrink_page_list() will as well call add_page_to_unevictable_list() in > > a loop. > > it's probability issue. > > readahead: we need to concern > (1) readahead vs readahead > (2) readahead vs reclaim > > vmscan: we need to concern > (3) background reclaim vs foreground reclaim > > So, (3) is rarely event than (1) and (2). > Am I missing anything? my last mail explanation is too poor. sorry. I don't dislike this patch concept. but it seems a bit naive against contention. if we can decrease contention risk, I can ack with presure. -- 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