From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail172.messagelabs.com (mail172.messagelabs.com [216.82.254.3]) by kanga.kvack.org (Postfix) with SMTP id 3B4766B006A for ; Thu, 14 Jan 2010 08:58:12 -0500 (EST) Date: Thu, 14 Jan 2010 21:24:51 +0800 From: Wu Fengguang Subject: Re: [ RESEND PATCH v3] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel Message-ID: <20100114132451.GA2546@localhost> References: <20100112170433.394be31b.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100112170433.394be31b.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: "Zheng, Shaohui" , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , "linux-kernel@vger.kernel.org" , "ak@linux.intel.com" , "y-goto@jp.fujitsu.com" , Dave Hansen , "x86@kernel.org" List-ID: Kame, On Tue, Jan 12, 2010 at 05:04:33PM +0900, KAMEZAWA Hiroyuki wrote: > 3 points... > 1. I think this patch cannot be compiled in archs other than x86. Right ? > IOW, please add static inline dummy... Good catch! > 2. pgdat->[start,end], totalram_pages etc...are updated at memory hotplug. > Please place the hook nearby them. arch/x86/mm/init_64.c:arch_add_memory() updates max_pfn_mapped, in this sense it's equally OK to update max_pfn/max_low_pfn etc before the call to arch_add_memory() ;) > 3. I recommend you yo use memory hotplug notifier. > If it's allowed, it will be cleaner. Hmm, notifier is for _outsider_ subsystems. It smells a bit overkill to do notifier _inside_ the hotplug code. > It seems there are no strict ordering to update parameters this patch touches. I tend to agree. That said, it does help keep our mind straight if we do it in some logical order: max_pfn => max_pfn_mapped => totalram_pages etc. Thanks, Fengguang -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org