From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 489ED6B00BE for ; Mon, 23 Mar 2009 03:59:41 -0400 (EDT) Received: from mt1.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail6.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id n2N91A1N015909 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Mon, 23 Mar 2009 18:01:10 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id B164845DE54 for ; Mon, 23 Mar 2009 18:01:09 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id 891F845DE50 for ; Mon, 23 Mar 2009 18:01:09 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 69F0AE08003 for ; Mon, 23 Mar 2009 18:01:09 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.249.87.103]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 1C1DE1DB8037 for ; Mon, 23 Mar 2009 18:01:09 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [patch 3/3] mm: keep pages from unevictable mappings off the LRU lists In-Reply-To: <20090323084254.GA1685@cmpxchg.org> References: <20090323111615.69F3.A69D9226@jp.fujitsu.com> <20090323084254.GA1685@cmpxchg.org> Message-Id: <20090323175507.6A18.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Mon, 23 Mar 2009 18:01:07 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: kosaki.motohiro@jp.fujitsu.com, 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: > On Mon, Mar 23, 2009 at 11:21:36AM +0900, KOSAKI Motohiro wrote: > > > Hmm,, > > > > > > This patch is another thing unlike previous series patches. > > > Firstly, It looked good to me. > > > > > > I think add_to_page_cache_lru have to become a fast path. > > > But, how often would ramfs and shmem function be called ? > > > > > > I have a concern for this patch to add another burden. > > > so, we need any numbers for getting pros and cons. > > > > > > Any thoughts ? > > > > 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? -- 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