From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Lameter Subject: [22/41] compound pages: Add new support functions Date: Mon, 10 Sep 2007 23:04:12 -0700 Message-ID: <20070911060430.424260145@sgi.com> References: <20070911060349.993975297@sgi.com> Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org To: torvalds@linux-foundation.org Return-path: Received: from netops-testserver-3-out.sgi.com ([192.48.171.28]:50593 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1761468AbXIKGEc (ORCPT ); Tue, 11 Sep 2007 02:04:32 -0400 Cc: Christoph Hellwig , Mel Gorman Cc: William Lee Irwin III , David Chinner Cc: Jens Axboe , Badari Pulavarty Cc: Maxim Levitsky , Fengguang Wu Cc: swin wang , totty.lu@gmail.com, hugh@veritas.com Cc: joern@lazybastard.org Content-Disposition: inline; filename=0022-compound-pages-Add-new-support-functions.patch Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org compound_pages(page) -> Determines base pages of a compound page compound_shift(page) -> Determine the page shift of a compound page compound_size(page) -> Determine the size of a compound page Signed-off-by: Christoph Lameter --- include/linux/mm.h | 15 +++++++++++++++ 1 files changed, 15 insertions(+), 0 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 1692dd6..6f3a8d6 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -363,6 +363,21 @@ static inline void set_compound_order(struct page *page, unsigned long order) page[1].lru.prev = (void *)order; } +static inline int compound_pages(struct page *page) +{ + return 1 << compound_order(page); +} + +static inline int compound_shift(struct page *page) +{ + return PAGE_SHIFT + compound_order(page); +} + +static inline int compound_size(struct page *page) +{ + return PAGE_SIZE << compound_order(page); +} + /* * Multiple processes may "see" the same page. E.g. for untouched * mappings of /dev/null, all processes see the same page full of -- 1.5.2.5 --