Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753263Ab2KUEA3 (ORCPT ); Tue, 20 Nov 2012 23:00:29 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:40236 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752748Ab2KUEA2 (ORCPT ); Tue, 20 Nov 2012 23:00:28 -0500 X-IronPort-AV: E=Sophos;i="4.83,290,1352044800"; d="scan'208";a="6243549" Message-ID: <50AC4A1B.9020908@cn.fujitsu.com> Date: Wed, 21 Nov 2012 11:27:23 +0800 From: Wen Congyang User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100413 Fedora/3.0.4-2.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Andrew Morton CC: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Rob Landley , Yasuaki Ishimatsu , Lai Jiangshan , Jiang Liu , KOSAKI Motohiro , Minchan Kim , Mel Gorman , David Rientjes , Yinghai Lu , Rusty Russell Subject: Re: [PART4 Patch v2 1/2] numa: add CONFIG_MOVABLE_NODE for movable-dedicated node References: <1353067090-19468-1-git-send-email-wency@cn.fujitsu.com> <1353067090-19468-2-git-send-email-wency@cn.fujitsu.com> <20121120142550.5c126194.akpm@linux-foundation.org> In-Reply-To: <20121120142550.5c126194.akpm@linux-foundation.org> X-MIMETrack: Itemize by SMTP Server on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/21 11:20:45, Serialize by Router on mailserver/fnst(Release 8.5.3|September 15, 2011) at 2012/11/21 11:20:51, Serialize complete at 2012/11/21 11:20:51 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2088 Lines: 58 At 11/21/2012 06:25 AM, Andrew Morton Wrote: > On Fri, 16 Nov 2012 19:58:09 +0800 > Wen Congyang wrote: > >> From: Lai Jiangshan >> >> All are prepared, we can actually introduce N_MEMORY. >> add CONFIG_MOVABLE_NODE make we can use it for movable-dedicated node > > This description is far too short on details. > > I grabbed this from the [0/n] email: > > : We need a node which only contains movable memory. This feature is very > : important for node hotplug. If a node has normal/highmem, the memory may > : be used by the kernel and can't be offlined. If the node only contains > : movable memory, we can offline the memory and the node. > > which helps a bit, but it's still pretty thin. > > Why is this option made configurable? Why not enable it unconditionally? > > Please send a patch which adds the Kconfig help text for > CONFIG_MOVABLE_NODE. Let's make that text nice and detailed. > > The name MOVABLE_NODE is not a good one. It means "a node which is > movable", whereas the concept is actually "a node whcih contains only > movable memory". I suppose we could change it to something like > CONFIG_MOVABLE_MEMORY_ONLY_NODE or similar. But I suppose that > CONFIG_MOVABLE_NODE is good enough, as long as it is well-described in > associated comments or help text. This is not the case at present. > >> +#ifdef CONFIG_MOVABLE_NODE >> + N_MEMORY, /* The node has memory(regular, high, movable) */ >> +#else > > I think the comment should be "The node has only movable memory"? No, the comment is right. In the kernel, we need the following two mask: 1. the node contains memory that the kernel can use(N_HIGH_MEMORY) 2. the node contains memory (N_MEMORY) There is no code need the mask: the node contains only movable memory now. Thanks Wen Congyang > > > -- 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/