From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754227Ab1HHUqz (ORCPT ); Mon, 8 Aug 2011 16:46:55 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:42486 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753418Ab1HHUqy (ORCPT ); Mon, 8 Aug 2011 16:46:54 -0400 Date: Mon, 8 Aug 2011 13:45:55 -0700 From: Dan Magenheimer To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, jeremy@goop.org, hughd@google.com, ngupta@vflare.org, konrad.wilk@oracle.com, JBeulich@novell.com, kurt.hackel@oracle.com, npiggin@kernel.dk, akpm@linux-foundation.org, riel@redhat.com, hannes@cmpxchg.org, matthew@wil.cx, chris.mason@oracle.com, dan.magenheimer@oracle.com, sjenning@linux.vnet.ibm.com, jackdachef@gmail.com Subject: Subject: [PATCH V6 1/4] mm: frontswap: swap data structure changes Message-ID: <20110808204555.GA15850@ca-server1.us.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.16 (2007-06-11) X-Source-IP: rtcsinet21.oracle.com [66.248.204.29] X-CT-RefId: str=0001.0A090207.4E404B0F.0061,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dan Magenheimer Subject: [PATCH V6 1/4] mm: frontswap: swap data structure changes This first patch of four in the frontswap series makes available core swap data structures (swap_lock, swap_list and swap_info) that are needed by frontswap.c but we don't need to expose them to the dozens of files that include swap.h so we create a new swapfile.h just to extern-ify these. Also add frontswap-related elements to swap_info_struct. Frontswap_map points to vzalloc'ed one-bit-per-swap-page metadata that indicates whether the swap page is in frontswap or in the device and frontswap_pages counts how many pages are in frontswap. We don't tie these to CONFIG_FRONTSWAP to avoid unnecessary clutter around various frontswap hooks. [v6: rebase to 3.0-rc1] [v5: no change from v4] [v4: rebase to 2.6.39] Signed-off-by: Dan Magenheimer Reviewed-by: Konrad Wilk Acked-by: Seth Jennings Cc: Jeremy Fitzhardinge Cc: Hugh Dickins Cc: Johannes Weiner Cc: Nitin Gupta Cc: Matthew Wilcox Cc: Chris Mason Cc: Jan Beulich Cc: Rik Riel Cc: Andrew Morton --- linux/include/linux/swapfile.h 1969-12-31 17:00:00.000000000 -0700 +++ frontswap/include/linux/swapfile.h 2011-08-08 08:59:03.951694506 -0600 @@ -0,0 +1,13 @@ +#ifndef _LINUX_SWAPFILE_H +#define _LINUX_SWAPFILE_H + +/* + * these were static in swapfile.c but frontswap.c needs them and we don't + * want to expose them to the dozens of source files that include swap.h + */ +extern spinlock_t swap_lock; +extern struct swap_list_t swap_list; +extern struct swap_info_struct *swap_info[]; +extern int try_to_unuse(unsigned int, bool, unsigned long); + +#endif /* _LINUX_SWAPFILE_H */ --- linux/include/linux/swap.h 2011-08-08 08:19:25.880690134 -0600 +++ frontswap/include/linux/swap.h 2011-08-08 08:59:03.952691415 -0600 @@ -194,6 +194,8 @@ struct swap_info_struct { struct block_device *bdev; /* swap device or bdev of swap file */ struct file *swap_file; /* seldom referenced */ unsigned int old_block_size; /* seldom referenced */ + unsigned long *frontswap_map; /* frontswap in-use, one bit per page */ + unsigned int frontswap_pages; /* frontswap pages in-use counter */ }; struct swap_list_t {