From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Hansen Subject: Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug Date: Tue, 04 Nov 2008 07:39:42 -0800 Message-ID: <1225813182.12673.587.camel@nimitz> References: <20081029105956.GA16347@atrey.karlin.mff.cuni.cz> <200811040954.34969.rjw@sisk.pl> <1225812111.12673.577.camel@nimitz> <200811041635.49932.rjw@sisk.pl> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <200811041635.49932.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: Nigel Cunningham , Matt Tolentino , linux-pm@lists.osdl.org, Dave Hansen , linux-kernel@vger.kernel.org, linux-mm@kvack.org, pavel@suse.cz, Mel Gorman , Andy Whitcroft , Andrew Morton List-Id: linux-pm@vger.kernel.org On Tue, 2008-11-04 at 16:35 +0100, Rafael J. Wysocki wrote: > On Tuesday, 4 of November 2008, Dave Hansen wrote: > > On Tue, 2008-11-04 at 09:54 +0100, Rafael J. Wysocki wrote: > > > To handle this, I need to know two things: > > > 1) what changes of the zones are possible due to memory hotplugging > > > (i.e. can they grow, shring, change boundaries etc.) > > > > All of the above. > > OK > > If I allocate a page frame corresponding to specific pfn, is it guaranteed to > be associated with the same pfn in future? Page allocation is different. Since you hold a reference to a page, it can not be removed until you release that reference. That's why every normal alloc_pages() user in the kernel doesn't have to worry about memory hotplug. > > Why walk zones instead of pgdats? > > This is a historical thing rather than anything else. I think we could switch > to pgdats, but that would require a code rewrite that's likely to introduce > bugs, while our image-creating code is really well tested and doesn't change > very often. OK, fair enough. I just wanted you to know that there are options other than zones. -- Dave