Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761503AbZCSW0Q (ORCPT ); Thu, 19 Mar 2009 18:26:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758143AbZCSWZ7 (ORCPT ); Thu, 19 Mar 2009 18:25:59 -0400 Received: from smtp.ultrahosting.com ([74.213.174.254]:49612 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757384AbZCSWZ7 (ORCPT ); Thu, 19 Mar 2009 18:25:59 -0400 Date: Thu, 19 Mar 2009 18:22:38 -0400 (EDT) From: Christoph Lameter X-X-Sender: cl@qirst.com To: Mel Gorman cc: Linux Memory Management List , Pekka Enberg , Rik van Riel , KOSAKI Motohiro , Johannes Weiner , Nick Piggin , Linux Kernel Mailing List , Lin Ming , Zhang Yanmin , Peter Zijlstra Subject: Re: [PATCH 20/35] Use a pre-calculated value for num_online_nodes() In-Reply-To: <20090319212912.GB24586@csn.ul.ie> Message-ID: References: <1237196790-7268-1-git-send-email-mel@csn.ul.ie> <1237196790-7268-21-git-send-email-mel@csn.ul.ie> <20090316163626.GJ24293@csn.ul.ie> <20090318150833.GC4629@csn.ul.ie> <20090318180152.GB24462@csn.ul.ie> <20090319212912.GB24586@csn.ul.ie> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1808 Lines: 47 On Thu, 19 Mar 2009, Mel Gorman wrote: > This patch actually alters the API. node_set_online() called when > MAX_NUMNODES == 1 will now fail to compile. That situation wouldn't make > any sense anyway but is it intentional? Yes MAX_NUMNODES means that this is not a NUMA configuration. Setting an ode online would make no sense. Node 0 is always online. > For reference here is the patch I had for a similar goal which kept the > API as it was. I'll drop it if you prefer your own version. Lets look through it and get the best pieces from both. > static inline void node_set_state(int node, enum node_states state) > { > __node_set(node, &node_states[state]); > + if (state == N_ONLINE) > + nr_online_nodes = num_node_state(N_ONLINE); > } That assumes uses of node_set_state N_ONLINE. Are there such users or are all using node_set_online()? > @@ -449,7 +457,8 @@ static inline int num_node_state(enum node_states state) > node; \ > }) > > -#define num_online_nodes() num_node_state(N_ONLINE) > + > +#define num_online_nodes() (nr_online_nodes) > #define num_possible_nodes() num_node_state(N_POSSIBLE) > #define node_online(node) node_state((node), N_ONLINE) > #define node_possible(node) node_state((node), N_POSSIBLE) Hmmmm... Yes we could get rid of those. I'd also like to see nr_possible_nodes(). nr_possible_nodes is important if you want to check if the system could ever bring up a second node (which would make the current optimization not viable) whereas nr_online_nodes is the check for how many nodes are currently online. -- 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/