From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [linux-pm] [PATCH] hibernation should work ok with memory hotplug From: Nigel Cunningham In-Reply-To: <1225782572.12673.540.camel@nimitz> References: <20081029105956.GA16347@atrey.karlin.mff.cuni.cz> <20081103125108.46d0639e.akpm@linux-foundation.org> <1225747308.12673.486.camel@nimitz> <200811032324.02163.rjw@sisk.pl> <1225751665.12673.511.camel@nimitz> <1225771353.6755.16.camel@nigel-laptop> <1225782572.12673.540.camel@nimitz> Content-Type: text/plain Date: Tue, 04 Nov 2008 18:30:37 +1100 Message-Id: <1225783837.6755.33.camel@nigel-laptop> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Dave Hansen Cc: "Rafael J. Wysocki" , 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: Hi. On Mon, 2008-11-03 at 23:09 -0800, Dave Hansen wrote: > > So pfn 10 in the first node refers to the same memory as pfn 10 in the > > second node? > > Sure. But, remember that the pfns (and the entire physical address > space) is consistent across the entire system. It's not like both nodes > have an address and the kernel only "gives" it to one of them. > > There's real confusion about zone->zone_start/end_pfn, I think. *All* > that they mean is this: > > - zone_start_pfn is the lowest physical address present in the zone. > - zone_end_pfn is the highest physical address present in the zone > > That's *it*. Those numbers imply *nothing* about the pages between > them, except that there might be 0 or more pages in there belonging to > the same zone. > > "All pages in this zone lie between these two physical addresses." is > all they say. Okay. Thanks (and to Rafael). One other question, if I may. Would you please explain (or point me to an explanation) of PHYS_PFN_OFFSET/ARCH_PFN_OFFSET? I've been dealing occasionally with people wanting to have hibernation on arm, and I don't really get the concept or the implementation (particularly when it comes to trying to do the sort of iterating over zones and pfns that was being discussed in previous messages in this thread. Regards, Nigel -- 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