From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e5.ny.us.ibm.com (8.12.11/8.12.11) with ESMTP id k19HS2Oa019755 for ; Thu, 9 Feb 2006 12:28:02 -0500 Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay02.pok.ibm.com (8.12.10/NCO/VERS6.8) with ESMTP id k19HS2N6111386 for ; Thu, 9 Feb 2006 12:28:02 -0500 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.12.11/8.13.3) with ESMTP id k19HS2lY022418 for ; Thu, 9 Feb 2006 12:28:02 -0500 Subject: Re: [RFC] Removing page->flags From: Dave Hansen In-Reply-To: References: <1139381183.22509.186.camel@localhost> <1139427478.9452.6.camel@localhost.localdomain> Content-Type: text/plain Date: Thu, 09 Feb 2006 09:27:55 -0800 Message-Id: <1139506075.9209.9.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Magnus Damm Cc: Magnus Damm , linux-mm@kvack.org, Magnus Damm , Andy Whitcroft List-ID: On Thu, 2006-02-09 at 11:50 +0900, Magnus Damm wrote: > I realize that if struct page size is not a power of two we will end > up with struct page elements that cross a lot of page boundaries. But > is that really a problem? I thought we were safe if: > > 1) struct page could be any size > 2) zones have to start and end at pfn:s that are a multiple of > PAGE_SIZE > 3) for sparsemem, the smallest section size is 1 << (PAGE_SIZE * 2). Yeah, I've thought through some scenarios and I can't think of any where it breaks unless the section size is really small, or a non-power-of-two. But, I don't think it is as feasible for DISCONTIGMEM or normal FLATMEM configurations. -- Dave -- 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