From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <489314FE.7080900@linux-foundation.org> Date: Fri, 01 Aug 2008 08:51:58 -0500 From: Christoph Lameter MIME-Version: 1.0 Subject: Re: [RFC:Patch: 000/008](memory hotplug) rough idea of pgdat removing References: <20080731203549.2A3F.E1E9C6FF@jp.fujitsu.com> <4891C66A.3040302@linux-foundation.org> <20080801180522.EC97.E1E9C6FF@jp.fujitsu.com> In-Reply-To: <20080801180522.EC97.E1E9C6FF@jp.fujitsu.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Yasunori Goto Cc: Badari Pulavarty , Andrew Morton , Mel Gorman , linux-mm , Linux Kernel ML List-ID: Yasunori Goto wrote: > I thought it at first, but are there the following worst case? > > > CPU 0 CPU 1 > ------------------------------------------------------- > __alloc_pages() > > parsing_zonelist() > : > enter page_reclarim() > sleep (and remember zone) : > : > update zonelist and node_online_map > with stop_machine_run() > free pgdat(). > remove the Node electrically. > > wake up and touch remembered > zone, but it is removed > (Oops!!!) > > > > Anyway, I'm happy if there is better way than my poor idea. :-) > > Thanks for your comment. Duh. Then the use of RCU would also mean that all of reclaim must be in a rcu period. So reclaim cannot sleep anymore. -- 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