Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753055Ab2KTWZx (ORCPT ); Tue, 20 Nov 2012 17:25:53 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:39407 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752271Ab2KTWZw (ORCPT ); Tue, 20 Nov 2012 17:25:52 -0500 Date: Tue, 20 Nov 2012 14:25:50 -0800 From: Andrew Morton To: Wen Congyang 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 Message-Id: <20121120142550.5c126194.akpm@linux-foundation.org> In-Reply-To: <1353067090-19468-2-git-send-email-wency@cn.fujitsu.com> References: <1353067090-19468-1-git-send-email-wency@cn.fujitsu.com> <1353067090-19468-2-git-send-email-wency@cn.fujitsu.com> X-Mailer: Sylpheed 3.0.2 (GTK+ 2.20.1; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1693 Lines: 43 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"? -- 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/