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 ESMTP id CF8B88D003A for ; Mon, 14 Mar 2011 22:33:03 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp (unknown [10.0.50.74]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id EC8173EE0C3 for ; Tue, 15 Mar 2011 11:32:59 +0900 (JST) Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id CEBCA45DE4D for ; Tue, 15 Mar 2011 11:32:59 +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 B59D445DE53 for ; Tue, 15 Mar 2011 11:32:59 +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 A44E2E78004 for ; Tue, 15 Mar 2011 11:32:59 +0900 (JST) Received: from m105.s.css.fujitsu.com (m105.s.css.fujitsu.com [10.240.81.145]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 5F8F11DB8040 for ; Tue, 15 Mar 2011 11:32:59 +0900 (JST) From: KOSAKI Motohiro Subject: Re: [PATCH 2/2 v4]mm: batch activate_page() to reduce lock contention In-Reply-To: References: <1300154014.2337.74.camel@sli10-conroe> Message-Id: <20110315111641.3520.A69D9226@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Date: Tue, 15 Mar 2011 11:32:58 +0900 (JST) Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: kosaki.motohiro@jp.fujitsu.com, Shaohua Li , Andrew Morton , linux-mm , Andi Kleen , Rik van Riel , mel , Johannes Weiner > >> Why do we need CONFIG_SMP in only activate_page_pvecs? > >> The per-cpu of activate_page_pvecs consumes lots of memory in UP? > >> I don't think so. But if it consumes lots of memory, it's a problem > >> of per-cpu. > > No, not too much memory. > > > >> I can't understand why we should hanlde activate_page_pvecs specially. > >> Please, enlighten me. > > Not it's special. akpm asked me to do it this time. Reducing little > > memory is still worthy anyway, so that's it. We can do it for other > > pvecs too, in separate patch. > > Understandable but I don't like code separation by CONFIG_SMP for just > little bit enhance of memory usage. In future, whenever we use percpu, > do we have to implement each functions for both SMP and non-SMP? > Is it desirable? > Andrew, Is it really valuable? > > If everybody agree, I don't oppose such way. > But now I vote code cleanness than reduce memory footprint. FWIW, The ifdef was added for embedded concern. and I believe you are familiar with modern embedded trend than me. then, I have no objection to remove it if you don't need it. 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org