From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 7 Dec 2006 19:50:23 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][PATCH] vmemmap on sparsemem v2 [1/5] generic vmemmap on sparsemem Message-Id: <20061207195023.11cb3b52.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20061207101156.GB9059@osiris.ibm.com> References: <20061205214517.5ad924f6.kamezawa.hiroyu@jp.fujitsu.com> <20061205214902.b8454d67.kamezawa.hiroyu@jp.fujitsu.com> <20061206181317.GA10042@osiris.ibm.com> <20061207092042.33533708.kamezawa.hiroyu@jp.fujitsu.com> <20061207101156.GB9059@osiris.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Heiko Carstens Cc: clameter@sgi.com, linux-mm@kvack.org, clameter@engr.sgi.com, apw@shadowen.org List-ID: On Thu, 7 Dec 2006 11:11:56 +0100 Heiko Carstens wrote: > > > vmap_end is only page aligned if sizeof(struct page) and PAGES_PER_SECTION > > > play nicely together. Which may not be the case on 64 bit platforms where > > > sizeof(struct page) is not a power of two. > > > > > Now, (for example ia64) sizeof(struct page)=56 and PAGES_PER_SECTION=65536, > > Then, sizeof(struct page) * PAGES_PER_SECTION is page-aligned.(16kbytes pages.) > > sizeof(struct page) depends also on at least two CONFIG options. I don't > think it's a good idea to assume that everything is page aligned, just > because it works right now and only with certain kernel configurations... > At least the kernel build should fail if your assumptions are not true > anymore. > I'll add #error and check it. thanks. -Kame -- 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