Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762330Ab2KAVgT (ORCPT ); Thu, 1 Nov 2012 17:36:19 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:53611 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762288Ab2KAVgQ (ORCPT ); Thu, 1 Nov 2012 17:36:16 -0400 Date: Thu, 1 Nov 2012 14:36:14 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Wen Congyang cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, Rob Landley , Andrew Morton , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , Yinghai Lu , "rusty@rustcorp.com.au" Subject: Re: [PART3 Patch 00/14] introduce N_MEMORY In-Reply-To: <509212FC.8070802@cn.fujitsu.com> Message-ID: References: <1351670652-9932-1-git-send-email-wency@cn.fujitsu.com> <509212FC.8070802@cn.fujitsu.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) 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: 1386 Lines: 29 On Thu, 1 Nov 2012, Wen Congyang wrote: > > This doesn't describe why we need the new node state, unfortunately. It > > 1. Somethimes, we use the node which contains the memory that can be used by > kernel. > 2. Sometimes, we use the node which contains the memory. > > In case1, we use N_HIGH_MEMORY, and we use N_MEMORY in case2. > Yeah, that's clear, but the question is still _why_ we want two different nodemasks. I know that this part of the patchset simply introduces the new nodemask because the name "N_MEMORY" is more clear than "N_HIGH_MEMORY", but there's no real incentive for making that change by introducing a new nodemask where a simple rename would suffice. I can only assume that you want to later use one of them for a different purpose: those that do not include nodes that consist of only ZONE_MOVABLE. But that change for MPOL_BIND is nacked since it significantly changes the semantics of set_mempolicy() and you can't break userspace (see my response to that from yesterday). Until that problem is addressed, then there's no reason for the additional nodemask so nack on this series as well. -- 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/