Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752144AbZL2EFj (ORCPT ); Mon, 28 Dec 2009 23:05:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751530AbZL2EFi (ORCPT ); Mon, 28 Dec 2009 23:05:38 -0500 Received: from mail-px0-f189.google.com ([209.85.216.189]:47855 "EHLO mail-px0-f189.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751416AbZL2EFi (ORCPT ); Mon, 28 Dec 2009 23:05:38 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; b=MnXOSsioK1g3MPW/pekn5rCr2pdiVYliFPbxP87f7sJjzvODeKy4y8LtdYuRQ2zI6g /7U47vKorhxu2EjH6fQH65bzSTXvpf/ZsG1oqsDPxdu14jcXkMXiCbdpiSvGFU+XFTFR 7FM96tQ+Lvw3GzIZ32sesPAbsefYJvrhG+tgY= MIME-Version: 1.0 In-Reply-To: <20091228164451.A687.A69D9226@jp.fujitsu.com> References: <20091228164451.A687.A69D9226@jp.fujitsu.com> Date: Tue, 29 Dec 2009 13:05:37 +0900 Message-ID: <28c262360912282005x68315a62l7ffde637febc7646@mail.gmail.com> Subject: Re: [PATCH 1/4] vmstat: remove zone->lock from walk_zones_in_node From: Minchan Kim To: KOSAKI Motohiro Cc: LKML , linux-mm , Andrew Morton , Balbir Singh , Mel Gorman , KAMEZAWA Hiroyuki Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1354 Lines: 36 On Mon, Dec 28, 2009 at 4:47 PM, KOSAKI Motohiro wrote: > The zone->lock is one of performance critical locks. Then, it shouldn't > be hold for long time. Currently, we have four walk_zones_in_node() > usage and almost use-case don't need to hold zone->lock. I agree. We can use walk_zone_in_node freely to show the information related to zone. - frag_show_print : the number of free pages per order. - pagetypeinfo_showfree_print : the number of free page per migration type - pagetypeinfo_showblockcount_print : the number of pages in zone per migration type - zoneinfo_show_print : many info about zone. Do we want to show exact value? No. If we want it, it's not enough zone->lock only. After all, All of things would be transient value. > > Thus, this patch move locking responsibility from walk_zones_in_node > to its sub function. Also this patch kill unnecessary zone->lock taking. > > Cc: Mel Gorman > Signed-off-by: KOSAKI Motohiro Reviewed-by: Minchan Kim -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/