From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id E39586B00A5 for ; Mon, 18 Oct 2010 21:16:47 -0400 (EDT) Received: from m1.gw.fujitsu.co.jp ([10.0.50.71]) by fgwmail5.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o9J1Gj7N009984 for (envelope-from kosaki.motohiro@jp.fujitsu.com); Tue, 19 Oct 2010 10:16:45 +0900 Received: from smail (m1 [127.0.0.1]) by outgoing.m1.gw.fujitsu.co.jp (Postfix) with ESMTP id 2236045DE54 for ; Tue, 19 Oct 2010 10:16:45 +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 5D97B45DE52 for ; Tue, 19 Oct 2010 10:16:44 +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 00D8D1DB804A for ; Tue, 19 Oct 2010 10:16:44 +0900 (JST) Received: from m107.s.css.fujitsu.com (m107.s.css.fujitsu.com [10.249.87.107]) by s1.gw.fujitsu.co.jp (Postfix) with ESMTP id 6A48BE38002 for ; Tue, 19 Oct 2010 10:16:43 +0900 (JST) From: KOSAKI Motohiro Subject: Re: zone state overhead In-Reply-To: <20101018103941.GX30667@csn.ul.ie> References: <20101014120804.8B8F.A69D9226@jp.fujitsu.com> <20101018103941.GX30667@csn.ul.ie> Message-Id: <20101019100658.A1B3.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Date: Tue, 19 Oct 2010 10:16:42 +0900 (JST) Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: kosaki.motohiro@jp.fujitsu.com, Shaohua Li , "linux-mm@kvack.org" , "cl@linux.com" , Andrew Morton , David Rientjes , KAMEZAWA Hiroyuki List-ID: > > In this case, wakeup_kswapd() don't wake kswapd because > > > > --------------------------------------------------------------------------------- > > void wakeup_kswapd(struct zone *zone, int order) > > { > > pg_data_t *pgdat; > > > > if (!populated_zone(zone)) > > return; > > > > pgdat = zone->zone_pgdat; > > if (zone_watermark_ok(zone, order, low_wmark_pages(zone), 0, 0)) > > return; // HERE > > --------------------------------------------------------------------------------- > > > > So, if we take your approach, we need to know exact free pages in this. > > Good point! > > > But, zone_page_state_snapshot() is slow. that's dilemma. > > > > Very true. I'm prototyping a version of the patch that keeps > zone_page_state_snapshot but only uses is in wakeup_kswapd and > sleeping_prematurely. Ok, this might works. but note, if we are running IO intensive workload, wakeup_kswapd() is called very frequently. because it is called even though allocation is succeed. we need to request Shaohua run and mesure his problem workload. and can you please cc me when you post next version? I hope to review it too. Thanks. -- 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