Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759601Ab2EJN6F (ORCPT ); Thu, 10 May 2012 09:58:05 -0400 Received: from cantor2.suse.de ([195.135.220.15]:38047 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932515Ab2EJNyg (ORCPT ); Thu, 10 May 2012 09:54:36 -0400 From: Mel Gorman To: Andrew Morton Cc: Linux-MM , Linux-Netdev , Linux-NFS , LKML , David Miller , Trond Myklebust , Neil Brown , Christoph Hellwig , Peter Zijlstra , Mike Christie , Eric B Munson , Mel Gorman Subject: [PATCH 05/12] mm: swap: Implement generic handler for swap_activate Date: Thu, 10 May 2012 14:54:18 +0100 Message-Id: <1336658065-24851-6-git-send-email-mgorman@suse.de> X-Mailer: git-send-email 1.7.9.2 In-Reply-To: <1336658065-24851-1-git-send-email-mgorman@suse.de> References: <1336658065-24851-1-git-send-email-mgorman@suse.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8120 Lines: 290 The version of swap_activate introduced is sufficient for swap-over-NFS but would not provide enough information to implement a generic handler. This patch shuffles things slightly to ensure the same information is available for aops->swap_activate() as is available to the core. No functionality change. Signed-off-by: Mel Gorman --- include/linux/fs.h | 6 ++-- include/linux/swap.h | 5 +++ mm/page_io.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++ mm/swapfile.c | 91 +++---------------------------------------------- 4 files changed, 106 insertions(+), 88 deletions(-) diff --git a/include/linux/fs.h b/include/linux/fs.h index 0dcd1e8..d48e8b8 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -417,6 +417,7 @@ struct kstatfs; struct vm_area_struct; struct vfsmount; struct cred; +struct swap_info_struct; extern void __init inode_init(void); extern void __init inode_init_early(void); @@ -628,8 +629,9 @@ struct address_space_operations { int (*error_remove_page)(struct address_space *, struct page *); /* swapfile support */ - int (*swap_activate)(struct file *file); - int (*swap_deactivate)(struct file *file); + int (*swap_activate)(struct swap_info_struct *sis, struct file *file, + sector_t *span); + void (*swap_deactivate)(struct file *file); }; extern const struct address_space_operations empty_aops; diff --git a/include/linux/swap.h b/include/linux/swap.h index 6b40350..4ab2276 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -320,6 +320,11 @@ extern int swap_writepage(struct page *page, struct writeback_control *wbc); extern int swap_set_page_dirty(struct page *page); extern void end_swap_bio_read(struct bio *bio, int err); +int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, + unsigned long nr_pages, sector_t start_block); +int generic_swapfile_activate(struct swap_info_struct *, struct file *, + sector_t *); + /* linux/mm/swap_state.c */ extern struct address_space swapper_space; #define total_swapcache_pages swapper_space.nrpages diff --git a/mm/page_io.c b/mm/page_io.c index 68d8357..f363261 100644 --- a/mm/page_io.c +++ b/mm/page_io.c @@ -86,6 +86,98 @@ void end_swap_bio_read(struct bio *bio, int err) bio_put(bio); } +int generic_swapfile_activate(struct swap_info_struct *sis, + struct file *swap_file, + sector_t *span) +{ + struct address_space *mapping = swap_file->f_mapping; + struct inode *inode = mapping->host; + unsigned blocks_per_page; + unsigned long page_no; + unsigned blkbits; + sector_t probe_block; + sector_t last_block; + sector_t lowest_block = -1; + sector_t highest_block = 0; + int nr_extents = 0; + int ret; + + blkbits = inode->i_blkbits; + blocks_per_page = PAGE_SIZE >> blkbits; + + /* + * Map all the blocks into the extent list. This code doesn't try + * to be very smart. + */ + probe_block = 0; + page_no = 0; + last_block = i_size_read(inode) >> blkbits; + while ((probe_block + blocks_per_page) <= last_block && + page_no < sis->max) { + unsigned block_in_page; + sector_t first_block; + + first_block = bmap(inode, probe_block); + if (first_block == 0) + goto bad_bmap; + + /* + * It must be PAGE_SIZE aligned on-disk + */ + if (first_block & (blocks_per_page - 1)) { + probe_block++; + goto reprobe; + } + + for (block_in_page = 1; block_in_page < blocks_per_page; + block_in_page++) { + sector_t block; + + block = bmap(inode, probe_block + block_in_page); + if (block == 0) + goto bad_bmap; + if (block != first_block + block_in_page) { + /* Discontiguity */ + probe_block++; + goto reprobe; + } + } + + first_block >>= (PAGE_SHIFT - blkbits); + if (page_no) { /* exclude the header page */ + if (first_block < lowest_block) + lowest_block = first_block; + if (first_block > highest_block) + highest_block = first_block; + } + + /* + * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks + */ + ret = add_swap_extent(sis, page_no, 1, first_block); + if (ret < 0) + goto out; + nr_extents += ret; + page_no++; + probe_block += blocks_per_page; +reprobe: + continue; + } + ret = nr_extents; + *span = 1 + highest_block - lowest_block; + if (page_no == 0) + page_no = 1; /* force Empty message */ + sis->max = page_no; + sis->pages = page_no - 1; + sis->highest_bit = page_no - 1; +out: + return ret; +bad_bmap: + printk(KERN_ERR "swapon: swapfile has holes\n"); + ret = -EINVAL; + goto out; +} + /* * We may have stale swap cache pages in memory: notice * them here and get rid of the unnecessary final write. diff --git a/mm/swapfile.c b/mm/swapfile.c index fe2ed44..80b3415 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1358,7 +1358,7 @@ static void destroy_swap_extents(struct swap_info_struct *sis) * * This function rather assumes that it is called in ascending page order. */ -static int +int add_swap_extent(struct swap_info_struct *sis, unsigned long start_page, unsigned long nr_pages, sector_t start_block) { @@ -1434,106 +1434,25 @@ static int setup_swap_extents(struct swap_info_struct *sis, sector_t *span) struct file *swap_file = sis->swap_file; struct address_space *mapping = swap_file->f_mapping; struct inode *inode = mapping->host; - unsigned blocks_per_page; - unsigned long page_no; - unsigned blkbits; - sector_t probe_block; - sector_t last_block; - sector_t lowest_block = -1; - sector_t highest_block = 0; - int nr_extents = 0; int ret; if (S_ISBLK(inode->i_mode)) { ret = add_swap_extent(sis, 0, sis->max, 0); *span = sis->pages; - goto out; + return ret; } if (mapping->a_ops->swap_activate) { - ret = mapping->a_ops->swap_activate(swap_file); + ret = mapping->a_ops->swap_activate(sis, swap_file, span); if (!ret) { sis->flags |= SWP_FILE; ret = add_swap_extent(sis, 0, sis->max, 0); *span = sis->pages; } - goto out; + return ret; } - blkbits = inode->i_blkbits; - blocks_per_page = PAGE_SIZE >> blkbits; - - /* - * Map all the blocks into the extent list. This code doesn't try - * to be very smart. - */ - probe_block = 0; - page_no = 0; - last_block = i_size_read(inode) >> blkbits; - while ((probe_block + blocks_per_page) <= last_block && - page_no < sis->max) { - unsigned block_in_page; - sector_t first_block; - - first_block = bmap(inode, probe_block); - if (first_block == 0) - goto bad_bmap; - - /* - * It must be PAGE_SIZE aligned on-disk - */ - if (first_block & (blocks_per_page - 1)) { - probe_block++; - goto reprobe; - } - - for (block_in_page = 1; block_in_page < blocks_per_page; - block_in_page++) { - sector_t block; - - block = bmap(inode, probe_block + block_in_page); - if (block == 0) - goto bad_bmap; - if (block != first_block + block_in_page) { - /* Discontiguity */ - probe_block++; - goto reprobe; - } - } - - first_block >>= (PAGE_SHIFT - blkbits); - if (page_no) { /* exclude the header page */ - if (first_block < lowest_block) - lowest_block = first_block; - if (first_block > highest_block) - highest_block = first_block; - } - - /* - * We found a PAGE_SIZE-length, PAGE_SIZE-aligned run of blocks - */ - ret = add_swap_extent(sis, page_no, 1, first_block); - if (ret < 0) - goto out; - nr_extents += ret; - page_no++; - probe_block += blocks_per_page; -reprobe: - continue; - } - ret = nr_extents; - *span = 1 + highest_block - lowest_block; - if (page_no == 0) - page_no = 1; /* force Empty message */ - sis->max = page_no; - sis->pages = page_no - 1; - sis->highest_bit = page_no - 1; -out: - return ret; -bad_bmap: - printk(KERN_ERR "swapon: swapfile has holes\n"); - ret = -EINVAL; - goto out; + return generic_swapfile_activate(sis, swap_file, span); } static void enable_swap_info(struct swap_info_struct *p, int prio, -- 1.7.9.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/