From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <46E83A19.2090604@google.com> Date: Wed, 12 Sep 2007 12:12:25 -0700 From: Martin Bligh MIME-Version: 1.0 Subject: Re: [RFC][PATCH] overwride page->mapping [0/3] intro References: <20070912114322.e4d8a86e.kamezawa.hiroyu@jp.fujitsu.com> <46E7A666.7080409@linux.vnet.ibm.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Balbir Singh , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "nickpiggin@yahoo.com.au" , "Lee.Schermerhorn@hp.com" , Andrew Morton List-ID: Christoph Lameter wrote: > On Wed, 12 Sep 2007, Balbir Singh wrote: > >> We discussed the struct page size issue at VM summit. If I remember >> correctly, Linus suggested that we consider using pfn's instead of >> pointers for pointer members in struct page. > > How would that save any memory? On a system with 16TB memory and 4k page > size you have at least 4 billion pfns which is the max that an unsigned > int can handle. If the virtual address space is sparse or larger (like on > IA64) then you need to use an int with more than 32 bit anyways. Because nobody (sane) has 16TB of memory? ;-) M. -- 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