Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2 | /* |
| 3 | * linux/mm/swap_state.c |
| 4 | * |
| 5 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 6 | * Swap reorganised 29.12.95, Stephen Tweedie |
| 7 | * |
| 8 | * Rewritten to use page cache, (C) 1998 Stephen Tweedie |
| 9 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/mm.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 11 | #include <linux/gfp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 12 | #include <linux/kernel_stat.h> |
| 13 | #include <linux/swap.h> |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 14 | #include <linux/swapops.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | #include <linux/init.h> |
| 16 | #include <linux/pagemap.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 17 | #include <linux/backing-dev.h> |
Christian Ehrhardt | 3fb5c29 | 2012-07-31 16:41:44 -0700 | [diff] [blame] | 18 | #include <linux/blkdev.h> |
Hugh Dickins | c484d41 | 2006-01-06 00:10:55 -0800 | [diff] [blame] | 19 | #include <linux/pagevec.h> |
Christoph Lameter | b20a350 | 2006-03-22 00:09:12 -0800 | [diff] [blame] | 20 | #include <linux/migrate.h> |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 21 | #include <linux/vmalloc.h> |
Tim Chen | 67afa38 | 2017-02-22 15:45:39 -0800 | [diff] [blame] | 22 | #include <linux/swap_slots.h> |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 23 | #include <linux/huge_mm.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 24 | |
| 25 | #include <asm/pgtable.h> |
Hugh Dickins | fa11088 | 2020-06-25 20:29:59 -0700 | [diff] [blame] | 26 | #include "internal.h" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | |
| 28 | /* |
| 29 | * swapper_space is a fiction, retained to simplify the path through |
Jens Axboe | 7eaceac | 2011-03-10 08:52:07 +0100 | [diff] [blame] | 30 | * vmscan's shrink_page_list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | */ |
Christoph Hellwig | f5e54d6 | 2006-06-28 04:26:44 -0700 | [diff] [blame] | 32 | static const struct address_space_operations swap_aops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | .writepage = swap_writepage, |
Mel Gorman | 62c230b | 2012-07-31 16:44:55 -0700 | [diff] [blame] | 34 | .set_page_dirty = swap_set_page_dirty, |
Andrew Morton | 1c93923 | 2014-10-09 15:27:59 -0700 | [diff] [blame] | 35 | #ifdef CONFIG_MIGRATION |
Christoph Lameter | e965f96 | 2006-02-01 03:05:41 -0800 | [diff] [blame] | 36 | .migratepage = migrate_page, |
Andrew Morton | 1c93923 | 2014-10-09 15:27:59 -0700 | [diff] [blame] | 37 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | }; |
| 39 | |
Changbin Du | 783cb68 | 2017-11-15 17:36:06 -0800 | [diff] [blame] | 40 | struct address_space *swapper_spaces[MAX_SWAPFILES] __read_mostly; |
| 41 | static unsigned int nr_swapper_spaces[MAX_SWAPFILES] __read_mostly; |
Colin Ian King | f5c754d | 2018-04-05 16:25:05 -0700 | [diff] [blame] | 42 | static bool enable_vma_readahead __read_mostly = true; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 43 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 44 | #define SWAP_RA_WIN_SHIFT (PAGE_SHIFT / 2) |
| 45 | #define SWAP_RA_HITS_MASK ((1UL << SWAP_RA_WIN_SHIFT) - 1) |
| 46 | #define SWAP_RA_HITS_MAX SWAP_RA_HITS_MASK |
| 47 | #define SWAP_RA_WIN_MASK (~PAGE_MASK & ~SWAP_RA_HITS_MASK) |
| 48 | |
| 49 | #define SWAP_RA_HITS(v) ((v) & SWAP_RA_HITS_MASK) |
| 50 | #define SWAP_RA_WIN(v) (((v) & SWAP_RA_WIN_MASK) >> SWAP_RA_WIN_SHIFT) |
| 51 | #define SWAP_RA_ADDR(v) ((v) & PAGE_MASK) |
| 52 | |
| 53 | #define SWAP_RA_VAL(addr, win, hits) \ |
| 54 | (((addr) & PAGE_MASK) | \ |
| 55 | (((win) << SWAP_RA_WIN_SHIFT) & SWAP_RA_WIN_MASK) | \ |
| 56 | ((hits) & SWAP_RA_HITS_MASK)) |
| 57 | |
| 58 | /* Initial readahead hits is 4 to start up with a small window */ |
| 59 | #define GET_SWAP_RA_VAL(vma) \ |
| 60 | (atomic_long_read(&(vma)->swap_readahead_info) ? : 4) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | |
| 62 | #define INC_CACHE_INFO(x) do { swap_cache_info.x++; } while (0) |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 63 | #define ADD_CACHE_INFO(x, nr) do { swap_cache_info.x += (nr); } while (0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
| 65 | static struct { |
| 66 | unsigned long add_total; |
| 67 | unsigned long del_total; |
| 68 | unsigned long find_success; |
| 69 | unsigned long find_total; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | } swap_cache_info; |
| 71 | |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 72 | unsigned long total_swapcache_pages(void) |
| 73 | { |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 74 | unsigned int i, j, nr; |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 75 | unsigned long ret = 0; |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 76 | struct address_space *spaces; |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 77 | |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 78 | rcu_read_lock(); |
| 79 | for (i = 0; i < MAX_SWAPFILES; i++) { |
| 80 | /* |
| 81 | * The corresponding entries in nr_swapper_spaces and |
| 82 | * swapper_spaces will be reused only after at least |
| 83 | * one grace period. So it is impossible for them |
| 84 | * belongs to different usage. |
| 85 | */ |
| 86 | nr = nr_swapper_spaces[i]; |
| 87 | spaces = rcu_dereference(swapper_spaces[i]); |
| 88 | if (!nr || !spaces) |
| 89 | continue; |
| 90 | for (j = 0; j < nr; j++) |
| 91 | ret += spaces[j].nrpages; |
| 92 | } |
| 93 | rcu_read_unlock(); |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 94 | return ret; |
| 95 | } |
| 96 | |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 97 | static atomic_t swapin_readahead_hits = ATOMIC_INIT(4); |
| 98 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | void show_swap_cache_info(void) |
| 100 | { |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 101 | printk("%lu pages in swap cache\n", total_swapcache_pages()); |
Johannes Weiner | 2c97b7f | 2008-07-25 19:46:01 -0700 | [diff] [blame] | 102 | printk("Swap cache stats: add %lu, delete %lu, find %lu/%lu\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | swap_cache_info.add_total, swap_cache_info.del_total, |
Hugh Dickins | bb63be0 | 2008-02-04 22:28:49 -0800 | [diff] [blame] | 104 | swap_cache_info.find_success, swap_cache_info.find_total); |
Shaohua Li | ec8acf2 | 2013-02-22 16:34:38 -0800 | [diff] [blame] | 105 | printk("Free swap = %ldkB\n", |
| 106 | get_nr_swap_pages() << (PAGE_SHIFT - 10)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 107 | printk("Total swap = %lukB\n", total_swap_pages << (PAGE_SHIFT - 10)); |
| 108 | } |
| 109 | |
| 110 | /* |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 111 | * __add_to_swap_cache resembles add_to_page_cache_locked on swapper_space, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | * but sets SwapCache flag and private instead of mapping and index. |
| 113 | */ |
Seth Jennings | 2f772e6 | 2013-04-29 15:08:34 -0700 | [diff] [blame] | 114 | int __add_to_swap_cache(struct page *page, swp_entry_t entry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 115 | { |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 116 | int error, i, nr = hpage_nr_pages(page); |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 117 | struct address_space *address_space; |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 118 | pgoff_t idx = swp_offset(entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 119 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 120 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
| 121 | VM_BUG_ON_PAGE(PageSwapCache(page), page); |
| 122 | VM_BUG_ON_PAGE(!PageSwapBacked(page), page); |
Hugh Dickins | 51726b1 | 2009-01-06 14:39:25 -0800 | [diff] [blame] | 123 | |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 124 | page_ref_add(page, nr); |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 125 | SetPageSwapCache(page); |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 126 | |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 127 | address_space = swap_address_space(entry); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 128 | xa_lock_irq(&address_space->i_pages); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 129 | for (i = 0; i < nr; i++) { |
| 130 | set_page_private(page + i, entry.val + i); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 131 | error = radix_tree_insert(&address_space->i_pages, |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 132 | idx + i, page + i); |
| 133 | if (unlikely(error)) |
| 134 | break; |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 135 | } |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 136 | if (likely(!error)) { |
| 137 | address_space->nrpages += nr; |
| 138 | __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, nr); |
| 139 | ADD_CACHE_INFO(add_total, nr); |
| 140 | } else { |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 141 | /* |
| 142 | * Only the context which have set SWAP_HAS_CACHE flag |
| 143 | * would call add_to_swap_cache(). |
| 144 | * So add_to_swap_cache() doesn't returns -EEXIST. |
| 145 | */ |
| 146 | VM_BUG_ON(error == -EEXIST); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 147 | set_page_private(page + i, 0UL); |
| 148 | while (i--) { |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 149 | radix_tree_delete(&address_space->i_pages, idx + i); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 150 | set_page_private(page + i, 0UL); |
| 151 | } |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 152 | ClearPageSwapCache(page); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 153 | page_ref_sub(page, nr); |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 154 | } |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 155 | xa_unlock_irq(&address_space->i_pages); |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 156 | |
| 157 | return error; |
| 158 | } |
| 159 | |
| 160 | |
| 161 | int add_to_swap_cache(struct page *page, swp_entry_t entry, gfp_t gfp_mask) |
| 162 | { |
| 163 | int error; |
| 164 | |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 165 | error = radix_tree_maybe_preload_order(gfp_mask, compound_order(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | if (!error) { |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 167 | error = __add_to_swap_cache(page, entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 168 | radix_tree_preload_end(); |
Hugh Dickins | fa1de90 | 2008-02-07 00:14:13 -0800 | [diff] [blame] | 169 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 170 | return error; |
| 171 | } |
| 172 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | /* |
| 174 | * This must be called only on pages that have |
| 175 | * been verified to be in the swap cache. |
| 176 | */ |
| 177 | void __delete_from_swap_cache(struct page *page) |
| 178 | { |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 179 | struct address_space *address_space; |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 180 | int i, nr = hpage_nr_pages(page); |
| 181 | swp_entry_t entry; |
| 182 | pgoff_t idx; |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 183 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 184 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
| 185 | VM_BUG_ON_PAGE(!PageSwapCache(page), page); |
| 186 | VM_BUG_ON_PAGE(PageWriteback(page), page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 188 | entry.val = page_private(page); |
| 189 | address_space = swap_address_space(entry); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 190 | idx = swp_offset(entry); |
| 191 | for (i = 0; i < nr; i++) { |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 192 | radix_tree_delete(&address_space->i_pages, idx + i); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 193 | set_page_private(page + i, 0); |
| 194 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | ClearPageSwapCache(page); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 196 | address_space->nrpages -= nr; |
| 197 | __mod_node_page_state(page_pgdat(page), NR_FILE_PAGES, -nr); |
| 198 | ADD_CACHE_INFO(del_total, nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | } |
| 200 | |
| 201 | /** |
| 202 | * add_to_swap - allocate swap space for a page |
| 203 | * @page: page we want to move to swap |
| 204 | * |
| 205 | * Allocate swap space for the page and add the page to the |
| 206 | * swap cache. Caller needs to hold the page lock. |
| 207 | */ |
Minchan Kim | 0f07465 | 2017-07-06 15:37:24 -0700 | [diff] [blame] | 208 | int add_to_swap(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | { |
| 210 | swp_entry_t entry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | int err; |
| 212 | |
Sasha Levin | 309381fea | 2014-01-23 15:52:54 -0800 | [diff] [blame] | 213 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
| 214 | VM_BUG_ON_PAGE(!PageUptodate(page), page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 215 | |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 216 | entry = get_swap_page(page); |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 217 | if (!entry.val) |
Minchan Kim | 0f07465 | 2017-07-06 15:37:24 -0700 | [diff] [blame] | 218 | return 0; |
| 219 | |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 220 | /* |
| 221 | * Radix-tree node allocations from PF_MEMALLOC contexts could |
| 222 | * completely exhaust the page allocator. __GFP_NOMEMALLOC |
| 223 | * stops emergency reserves from being allocated. |
| 224 | * |
| 225 | * TODO: this could cause a theoretical memory reclaim |
| 226 | * deadlock in the swap out path. |
| 227 | */ |
| 228 | /* |
Minchan Kim | 854e9ed | 2016-01-15 16:54:53 -0800 | [diff] [blame] | 229 | * Add it to the swap cache. |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 230 | */ |
| 231 | err = add_to_swap_cache(page, entry, |
| 232 | __GFP_HIGH|__GFP_NOMEMALLOC|__GFP_NOWARN); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 233 | /* -ENOMEM radix-tree allocation failure */ |
| 234 | if (err) |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 235 | /* |
| 236 | * add_to_swap_cache() doesn't return -EEXIST, so we can safely |
| 237 | * clear SWAP_HAS_CACHE flag. |
| 238 | */ |
Minchan Kim | 0f07465 | 2017-07-06 15:37:24 -0700 | [diff] [blame] | 239 | goto fail; |
Shaohua Li | 9625456 | 2017-10-03 16:15:32 -0700 | [diff] [blame] | 240 | /* |
| 241 | * Normally the page will be dirtied in unmap because its pte should be |
| 242 | * dirty. A special case is MADV_FREE page. The page'e pte could have |
| 243 | * dirty bit cleared but the page's SwapBacked bit is still set because |
| 244 | * clearing the dirty bit and SwapBacked bit has no lock protected. For |
| 245 | * such page, unmap will not set dirty bit for it, so page reclaim will |
| 246 | * not write the page out. This can cause data corruption when the page |
| 247 | * is swap in later. Always setting the dirty bit for the page solves |
| 248 | * the problem. |
| 249 | */ |
| 250 | set_page_dirty(page); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 251 | |
| 252 | return 1; |
| 253 | |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 254 | fail: |
Minchan Kim | 0f07465 | 2017-07-06 15:37:24 -0700 | [diff] [blame] | 255 | put_swap_page(page, entry); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 256 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | } |
| 258 | |
| 259 | /* |
| 260 | * This must be called only on pages that have |
| 261 | * been verified to be in the swap cache and locked. |
| 262 | * It will never put the page into the free list, |
| 263 | * the caller has a reference on the page. |
| 264 | */ |
| 265 | void delete_from_swap_cache(struct page *page) |
| 266 | { |
| 267 | swp_entry_t entry; |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 268 | struct address_space *address_space; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 269 | |
Hugh Dickins | 4c21e2f | 2005-10-29 18:16:40 -0700 | [diff] [blame] | 270 | entry.val = page_private(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 272 | address_space = swap_address_space(entry); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 273 | xa_lock_irq(&address_space->i_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | __delete_from_swap_cache(page); |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 275 | xa_unlock_irq(&address_space->i_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 276 | |
Minchan Kim | 75f6d6d | 2017-07-06 15:37:21 -0700 | [diff] [blame] | 277 | put_swap_page(page, entry); |
Huang Ying | 38d8b4e | 2017-07-06 15:37:18 -0700 | [diff] [blame] | 278 | page_ref_sub(page, hpage_nr_pages(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | } |
| 280 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | /* |
| 282 | * If we are the only user, then try to free up the swap cache. |
| 283 | * |
| 284 | * Its ok to check for PageSwapCache without the page lock |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 285 | * here because we are going to recheck again inside |
| 286 | * try_to_free_swap() _with_ the lock. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 287 | * - Marcelo |
| 288 | */ |
| 289 | static inline void free_swap_cache(struct page *page) |
| 290 | { |
Hugh Dickins | a2c43ee | 2009-01-06 14:39:36 -0800 | [diff] [blame] | 291 | if (PageSwapCache(page) && !page_mapped(page) && trylock_page(page)) { |
| 292 | try_to_free_swap(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | unlock_page(page); |
| 294 | } |
| 295 | } |
| 296 | |
| 297 | /* |
| 298 | * Perform a free_page(), also freeing any swap cache associated with |
Hugh Dickins | b8072f0 | 2005-10-29 18:16:41 -0700 | [diff] [blame] | 299 | * this page if it is the last user of the page. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | */ |
| 301 | void free_page_and_swap_cache(struct page *page) |
| 302 | { |
| 303 | free_swap_cache(page); |
Aaron Lu | 6fcb52a | 2016-10-07 17:00:08 -0700 | [diff] [blame] | 304 | if (!is_huge_zero_page(page)) |
Gerald Schaefer | 770a537 | 2016-06-08 15:33:50 -0700 | [diff] [blame] | 305 | put_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 306 | } |
| 307 | |
| 308 | /* |
| 309 | * Passed an array of pages, drop them all from swapcache and then release |
| 310 | * them. They are removed from the LRU and freed if this is their last use. |
| 311 | */ |
| 312 | void free_pages_and_swap_cache(struct page **pages, int nr) |
| 313 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | struct page **pagep = pages; |
Michal Hocko | aabfb57 | 2014-10-09 15:28:52 -0700 | [diff] [blame] | 315 | int i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | |
| 317 | lru_add_drain(); |
Michal Hocko | aabfb57 | 2014-10-09 15:28:52 -0700 | [diff] [blame] | 318 | for (i = 0; i < nr; i++) |
| 319 | free_swap_cache(pagep[i]); |
Mel Gorman | c6f92f9 | 2017-11-15 17:37:55 -0800 | [diff] [blame] | 320 | release_pages(pagep, nr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | } |
| 322 | |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 323 | static inline bool swap_use_vma_readahead(void) |
| 324 | { |
| 325 | return READ_ONCE(enable_vma_readahead) && !atomic_read(&nr_rotate_swap); |
| 326 | } |
| 327 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 328 | /* |
| 329 | * Lookup a swap entry in the swap cache. A found page will be returned |
| 330 | * unlocked and with its refcount incremented - we rely on the kernel |
| 331 | * lock getting page table operations atomic even if we drop the page |
| 332 | * lock before returning. |
| 333 | */ |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 334 | struct page *lookup_swap_cache(swp_entry_t entry, struct vm_area_struct *vma, |
| 335 | unsigned long addr) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | { |
| 337 | struct page *page; |
| 338 | |
Huang Ying | f6ab1f7 | 2016-10-07 17:00:21 -0700 | [diff] [blame] | 339 | page = find_get_page(swap_address_space(entry), swp_offset(entry)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 340 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 341 | INC_CACHE_INFO(find_total); |
| 342 | if (page) { |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 343 | bool vma_ra = swap_use_vma_readahead(); |
| 344 | bool readahead; |
| 345 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | INC_CACHE_INFO(find_success); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 347 | /* |
| 348 | * At the moment, we don't support PG_readahead for anon THP |
| 349 | * so let's bail out rather than confusing the readahead stat. |
| 350 | */ |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 351 | if (unlikely(PageTransCompound(page))) |
| 352 | return page; |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 353 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 354 | readahead = TestClearPageReadahead(page); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 355 | if (vma && vma_ra) { |
| 356 | unsigned long ra_val; |
| 357 | int win, hits; |
| 358 | |
| 359 | ra_val = GET_SWAP_RA_VAL(vma); |
| 360 | win = SWAP_RA_WIN(ra_val); |
| 361 | hits = SWAP_RA_HITS(ra_val); |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 362 | if (readahead) |
| 363 | hits = min_t(int, hits + 1, SWAP_RA_HITS_MAX); |
| 364 | atomic_long_set(&vma->swap_readahead_info, |
| 365 | SWAP_RA_VAL(addr, win, hits)); |
| 366 | } |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 367 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 368 | if (readahead) { |
Huang Ying | cbc65df | 2017-09-06 16:24:29 -0700 | [diff] [blame] | 369 | count_vm_event(SWAP_RA_HIT); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 370 | if (!vma || !vma_ra) |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 371 | atomic_inc(&swapin_readahead_hits); |
Huang Ying | cbc65df | 2017-09-06 16:24:29 -0700 | [diff] [blame] | 372 | } |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 373 | } |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 374 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 375 | return page; |
| 376 | } |
| 377 | |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 378 | struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, |
| 379 | struct vm_area_struct *vma, unsigned long addr, |
| 380 | bool *new_page_allocated) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 381 | { |
| 382 | struct page *found_page, *new_page = NULL; |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 383 | struct address_space *swapper_space = swap_address_space(entry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | int err; |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 385 | *new_page_allocated = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | |
| 387 | do { |
| 388 | /* |
| 389 | * First check the swap cache. Since this is normally |
| 390 | * called after lookup_swap_cache() failed, re-calling |
| 391 | * that would confuse statistics. |
| 392 | */ |
Huang Ying | f6ab1f7 | 2016-10-07 17:00:21 -0700 | [diff] [blame] | 393 | found_page = find_get_page(swapper_space, swp_offset(entry)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 394 | if (found_page) |
| 395 | break; |
| 396 | |
Huang Ying | ba81f83 | 2017-02-22 15:45:46 -0800 | [diff] [blame] | 397 | /* |
| 398 | * Just skip read ahead for unused swap slot. |
| 399 | * During swap_off when swap_slot_cache is disabled, |
| 400 | * we have to handle the race between putting |
| 401 | * swap entry in swap cache and marking swap slot |
| 402 | * as SWAP_HAS_CACHE. That's done in later part of code or |
| 403 | * else swap_off will be aborted if we return NULL. |
| 404 | */ |
| 405 | if (!__swp_swapcount(entry) && swap_slot_cache_enabled) |
| 406 | break; |
Tim Chen | e8c26ab | 2017-02-22 15:45:29 -0800 | [diff] [blame] | 407 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 408 | /* |
| 409 | * Get a new page to read into from swap. |
| 410 | */ |
| 411 | if (!new_page) { |
Hugh Dickins | 02098fe | 2008-02-04 22:28:42 -0800 | [diff] [blame] | 412 | new_page = alloc_page_vma(gfp_mask, vma, addr); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 413 | if (!new_page) |
| 414 | break; /* Out of memory */ |
| 415 | } |
| 416 | |
| 417 | /* |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 418 | * call radix_tree_preload() while we can wait. |
| 419 | */ |
Hugh Dickins | fa11088 | 2020-06-25 20:29:59 -0700 | [diff] [blame] | 420 | err = radix_tree_maybe_preload(gfp_mask & GFP_RECLAIM_MASK); |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 421 | if (err) |
| 422 | break; |
| 423 | |
| 424 | /* |
Hugh Dickins | f000944 | 2008-02-04 22:28:49 -0800 | [diff] [blame] | 425 | * Swap entry may have been freed since our caller observed it. |
| 426 | */ |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 427 | err = swapcache_prepare(entry); |
Rafael Aquini | cbab0e4 | 2013-06-12 14:04:49 -0700 | [diff] [blame] | 428 | if (err == -EEXIST) { |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 429 | radix_tree_preload_end(); |
Rafael Aquini | cbab0e4 | 2013-06-12 14:04:49 -0700 | [diff] [blame] | 430 | /* |
| 431 | * We might race against get_swap_page() and stumble |
| 432 | * across a SWAP_HAS_CACHE swap_map entry whose page |
Huang Ying | 9c1cc2e | 2017-05-03 14:54:33 -0700 | [diff] [blame] | 433 | * has not been brought into the swapcache yet. |
Rafael Aquini | cbab0e4 | 2013-06-12 14:04:49 -0700 | [diff] [blame] | 434 | */ |
| 435 | cond_resched(); |
KAMEZAWA Hiroyuki | 355cfa7 | 2009-06-16 15:32:53 -0700 | [diff] [blame] | 436 | continue; |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 437 | } |
| 438 | if (err) { /* swp entry is obsolete ? */ |
| 439 | radix_tree_preload_end(); |
Hugh Dickins | f000944 | 2008-02-04 22:28:49 -0800 | [diff] [blame] | 440 | break; |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 441 | } |
Hugh Dickins | f000944 | 2008-02-04 22:28:49 -0800 | [diff] [blame] | 442 | |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 443 | /* May fail (-ENOMEM) if radix-tree node allocation failed. */ |
Kirill A. Shutemov | 48c935a | 2016-01-15 16:51:24 -0800 | [diff] [blame] | 444 | __SetPageLocked(new_page); |
Hugh Dickins | fa9949d | 2016-05-19 17:12:41 -0700 | [diff] [blame] | 445 | __SetPageSwapBacked(new_page); |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 446 | err = __add_to_swap_cache(new_page, entry); |
Nick Piggin | 529ae9a | 2008-08-02 12:01:03 +0200 | [diff] [blame] | 447 | if (likely(!err)) { |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 448 | radix_tree_preload_end(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 449 | /* |
| 450 | * Initiate read into locked page and return. |
| 451 | */ |
Rik van Riel | c5fdae4 | 2008-10-18 20:26:36 -0700 | [diff] [blame] | 452 | lru_cache_add_anon(new_page); |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 453 | *new_page_allocated = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 454 | return new_page; |
| 455 | } |
Daisuke Nishimura | 31a5639 | 2009-09-21 17:02:50 -0700 | [diff] [blame] | 456 | radix_tree_preload_end(); |
Kirill A. Shutemov | 48c935a | 2016-01-15 16:51:24 -0800 | [diff] [blame] | 457 | __ClearPageLocked(new_page); |
Daisuke Nishimura | 2ca4532 | 2009-09-21 17:02:52 -0700 | [diff] [blame] | 458 | /* |
| 459 | * add_to_swap_cache() doesn't return -EEXIST, so we can safely |
| 460 | * clear SWAP_HAS_CACHE flag. |
| 461 | */ |
Minchan Kim | 75f6d6d | 2017-07-06 15:37:21 -0700 | [diff] [blame] | 462 | put_swap_page(new_page, entry); |
Hugh Dickins | f000944 | 2008-02-04 22:28:49 -0800 | [diff] [blame] | 463 | } while (err != -ENOMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | |
| 465 | if (new_page) |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 466 | put_page(new_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | return found_page; |
| 468 | } |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 469 | |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 470 | /* |
| 471 | * Locate a page of swap in physical memory, reserving swap cache space |
| 472 | * and reading the disk if it is not already cached. |
| 473 | * A failure return means that either the page allocation failed or that |
| 474 | * the swap entry is no longer in use. |
| 475 | */ |
| 476 | struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, |
Shaohua Li | 2395562 | 2017-07-10 15:47:11 -0700 | [diff] [blame] | 477 | struct vm_area_struct *vma, unsigned long addr, bool do_poll) |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 478 | { |
| 479 | bool page_was_allocated; |
| 480 | struct page *retpage = __read_swap_cache_async(entry, gfp_mask, |
| 481 | vma, addr, &page_was_allocated); |
| 482 | |
| 483 | if (page_was_allocated) |
Shaohua Li | 2395562 | 2017-07-10 15:47:11 -0700 | [diff] [blame] | 484 | swap_readpage(retpage, do_poll); |
Dmitry Safonov | 5b999aa | 2015-09-08 15:05:00 -0700 | [diff] [blame] | 485 | |
| 486 | return retpage; |
| 487 | } |
| 488 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 489 | static unsigned int __swapin_nr_pages(unsigned long prev_offset, |
| 490 | unsigned long offset, |
| 491 | int hits, |
| 492 | int max_pages, |
| 493 | int prev_win) |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 494 | { |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 495 | unsigned int pages, last_ra; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 496 | |
| 497 | /* |
| 498 | * This heuristic has been found to work well on both sequential and |
| 499 | * random loads, swapping to hard disk or to SSD: please don't ask |
| 500 | * what the "+ 2" means, it just happens to work well, that's all. |
| 501 | */ |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 502 | pages = hits + 2; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 503 | if (pages == 2) { |
| 504 | /* |
| 505 | * We can have no readahead hits to judge by: but must not get |
| 506 | * stuck here forever, so check for an adjacent offset instead |
| 507 | * (and don't even bother to check whether swap type is same). |
| 508 | */ |
| 509 | if (offset != prev_offset + 1 && offset != prev_offset - 1) |
| 510 | pages = 1; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 511 | } else { |
| 512 | unsigned int roundup = 4; |
| 513 | while (roundup < pages) |
| 514 | roundup <<= 1; |
| 515 | pages = roundup; |
| 516 | } |
| 517 | |
| 518 | if (pages > max_pages) |
| 519 | pages = max_pages; |
| 520 | |
| 521 | /* Don't shrink readahead too fast */ |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 522 | last_ra = prev_win / 2; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 523 | if (pages < last_ra) |
| 524 | pages = last_ra; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 525 | |
| 526 | return pages; |
| 527 | } |
| 528 | |
| 529 | static unsigned long swapin_nr_pages(unsigned long offset) |
| 530 | { |
| 531 | static unsigned long prev_offset; |
| 532 | unsigned int hits, pages, max_pages; |
| 533 | static atomic_t last_readahead_pages; |
| 534 | |
| 535 | max_pages = 1 << READ_ONCE(page_cluster); |
| 536 | if (max_pages <= 1) |
| 537 | return 1; |
| 538 | |
| 539 | hits = atomic_xchg(&swapin_readahead_hits, 0); |
| 540 | pages = __swapin_nr_pages(prev_offset, offset, hits, max_pages, |
| 541 | atomic_read(&last_readahead_pages)); |
| 542 | if (!hits) |
| 543 | prev_offset = offset; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 544 | atomic_set(&last_readahead_pages, pages); |
| 545 | |
| 546 | return pages; |
| 547 | } |
| 548 | |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 549 | /** |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 550 | * swap_cluster_readahead - swap in pages in hope we need them soon |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 551 | * @entry: swap entry of this memory |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 552 | * @gfp_mask: memory allocation flags |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 553 | * @vmf: fault information |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 554 | * |
| 555 | * Returns the struct page for entry and addr, after queueing swapin. |
| 556 | * |
| 557 | * Primitive swap readahead code. We simply read an aligned block of |
| 558 | * (1 << page_cluster) entries in the swap area. This method is chosen |
| 559 | * because it doesn't cost us any seek time. We also make sure to queue |
| 560 | * the 'original' request together with the readahead ones... |
| 561 | * |
| 562 | * This has been extended to use the NUMA policies from the mm triggering |
| 563 | * the readahead. |
| 564 | * |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 565 | * Caller must hold down_read on the vma->vm_mm if vmf->vma is not NULL. |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 566 | */ |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 567 | struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t gfp_mask, |
| 568 | struct vm_fault *vmf) |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 569 | { |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 570 | struct page *page; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 571 | unsigned long entry_offset = swp_offset(entry); |
| 572 | unsigned long offset = entry_offset; |
Rik van Riel | 67f96aa | 2012-03-21 16:33:50 -0700 | [diff] [blame] | 573 | unsigned long start_offset, end_offset; |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 574 | unsigned long mask; |
Huang Ying | e9a6eff | 2017-11-15 17:33:15 -0800 | [diff] [blame] | 575 | struct swap_info_struct *si = swp_swap_info(entry); |
Christian Ehrhardt | 3fb5c29 | 2012-07-31 16:41:44 -0700 | [diff] [blame] | 576 | struct blk_plug plug; |
Huang Ying | c4fa630 | 2017-09-06 16:24:33 -0700 | [diff] [blame] | 577 | bool do_poll = true, page_allocated; |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 578 | struct vm_area_struct *vma = vmf->vma; |
| 579 | unsigned long addr = vmf->address; |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 580 | |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 581 | mask = swapin_nr_pages(offset) - 1; |
| 582 | if (!mask) |
| 583 | goto skip; |
| 584 | |
Shaohua Li | 2395562 | 2017-07-10 15:47:11 -0700 | [diff] [blame] | 585 | do_poll = false; |
Rik van Riel | 67f96aa | 2012-03-21 16:33:50 -0700 | [diff] [blame] | 586 | /* Read a page_cluster sized and aligned cluster around offset. */ |
| 587 | start_offset = offset & ~mask; |
| 588 | end_offset = offset | mask; |
| 589 | if (!start_offset) /* First page is swap header. */ |
| 590 | start_offset++; |
Huang Ying | e9a6eff | 2017-11-15 17:33:15 -0800 | [diff] [blame] | 591 | if (end_offset >= si->max) |
| 592 | end_offset = si->max - 1; |
Rik van Riel | 67f96aa | 2012-03-21 16:33:50 -0700 | [diff] [blame] | 593 | |
Christian Ehrhardt | 3fb5c29 | 2012-07-31 16:41:44 -0700 | [diff] [blame] | 594 | blk_start_plug(&plug); |
Rik van Riel | 67f96aa | 2012-03-21 16:33:50 -0700 | [diff] [blame] | 595 | for (offset = start_offset; offset <= end_offset ; offset++) { |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 596 | /* Ok, do the async read-ahead now */ |
Huang Ying | c4fa630 | 2017-09-06 16:24:33 -0700 | [diff] [blame] | 597 | page = __read_swap_cache_async( |
| 598 | swp_entry(swp_type(entry), offset), |
| 599 | gfp_mask, vma, addr, &page_allocated); |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 600 | if (!page) |
Rik van Riel | 67f96aa | 2012-03-21 16:33:50 -0700 | [diff] [blame] | 601 | continue; |
Huang Ying | c4fa630 | 2017-09-06 16:24:33 -0700 | [diff] [blame] | 602 | if (page_allocated) { |
| 603 | swap_readpage(page, false); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 604 | if (offset != entry_offset) { |
Huang Ying | c4fa630 | 2017-09-06 16:24:33 -0700 | [diff] [blame] | 605 | SetPageReadahead(page); |
| 606 | count_vm_event(SWAP_RA); |
| 607 | } |
Huang Ying | cbc65df | 2017-09-06 16:24:29 -0700 | [diff] [blame] | 608 | } |
Kirill A. Shutemov | 09cbfea | 2016-04-01 15:29:47 +0300 | [diff] [blame] | 609 | put_page(page); |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 610 | } |
Christian Ehrhardt | 3fb5c29 | 2012-07-31 16:41:44 -0700 | [diff] [blame] | 611 | blk_finish_plug(&plug); |
| 612 | |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 613 | lru_add_drain(); /* Push any new pages onto the LRU now */ |
Shaohua Li | 579f829 | 2014-02-06 12:04:21 -0800 | [diff] [blame] | 614 | skip: |
Shaohua Li | 2395562 | 2017-07-10 15:47:11 -0700 | [diff] [blame] | 615 | return read_swap_cache_async(entry, gfp_mask, vma, addr, do_poll); |
Hugh Dickins | 46017e9 | 2008-02-04 22:28:41 -0800 | [diff] [blame] | 616 | } |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 617 | |
| 618 | int init_swap_address_space(unsigned int type, unsigned long nr_pages) |
| 619 | { |
| 620 | struct address_space *spaces, *space; |
| 621 | unsigned int i, nr; |
| 622 | |
| 623 | nr = DIV_ROUND_UP(nr_pages, SWAP_ADDRESS_SPACE_PAGES); |
Kees Cook | 778e1cd | 2018-06-12 14:04:48 -0700 | [diff] [blame] | 624 | spaces = kvcalloc(nr, sizeof(struct address_space), GFP_KERNEL); |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 625 | if (!spaces) |
| 626 | return -ENOMEM; |
| 627 | for (i = 0; i < nr; i++) { |
| 628 | space = spaces + i; |
Matthew Wilcox | b93b016 | 2018-04-10 16:36:56 -0700 | [diff] [blame] | 629 | INIT_RADIX_TREE(&space->i_pages, GFP_ATOMIC|__GFP_NOWARN); |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 630 | atomic_set(&space->i_mmap_writable, 0); |
| 631 | space->a_ops = &swap_aops; |
| 632 | /* swap cache doesn't use writeback related tags */ |
| 633 | mapping_set_no_writeback_tags(space); |
Huang, Ying | 4b3ef9d | 2017-02-22 15:45:26 -0800 | [diff] [blame] | 634 | } |
| 635 | nr_swapper_spaces[type] = nr; |
| 636 | rcu_assign_pointer(swapper_spaces[type], spaces); |
| 637 | |
| 638 | return 0; |
| 639 | } |
| 640 | |
| 641 | void exit_swap_address_space(unsigned int type) |
| 642 | { |
| 643 | struct address_space *spaces; |
| 644 | |
| 645 | spaces = swapper_spaces[type]; |
| 646 | nr_swapper_spaces[type] = 0; |
| 647 | rcu_assign_pointer(swapper_spaces[type], NULL); |
| 648 | synchronize_rcu(); |
| 649 | kvfree(spaces); |
| 650 | } |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 651 | |
| 652 | static inline void swap_ra_clamp_pfn(struct vm_area_struct *vma, |
| 653 | unsigned long faddr, |
| 654 | unsigned long lpfn, |
| 655 | unsigned long rpfn, |
| 656 | unsigned long *start, |
| 657 | unsigned long *end) |
| 658 | { |
| 659 | *start = max3(lpfn, PFN_DOWN(vma->vm_start), |
| 660 | PFN_DOWN(faddr & PMD_MASK)); |
| 661 | *end = min3(rpfn, PFN_DOWN(vma->vm_end), |
| 662 | PFN_DOWN((faddr & PMD_MASK) + PMD_SIZE)); |
| 663 | } |
| 664 | |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 665 | static void swap_ra_info(struct vm_fault *vmf, |
| 666 | struct vma_swap_readahead *ra_info) |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 667 | { |
| 668 | struct vm_area_struct *vma = vmf->vma; |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 669 | unsigned long ra_val; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 670 | swp_entry_t entry; |
| 671 | unsigned long faddr, pfn, fpfn; |
| 672 | unsigned long start, end; |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 673 | pte_t *pte, *orig_pte; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 674 | unsigned int max_win, hits, prev_win, win, left; |
| 675 | #ifndef CONFIG_64BIT |
| 676 | pte_t *tpte; |
| 677 | #endif |
| 678 | |
Huang Ying | 61b6397 | 2017-10-13 15:58:29 -0700 | [diff] [blame] | 679 | max_win = 1 << min_t(unsigned int, READ_ONCE(page_cluster), |
| 680 | SWAP_RA_ORDER_CEILING); |
| 681 | if (max_win == 1) { |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 682 | ra_info->win = 1; |
| 683 | return; |
Huang Ying | 61b6397 | 2017-10-13 15:58:29 -0700 | [diff] [blame] | 684 | } |
| 685 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 686 | faddr = vmf->address; |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 687 | orig_pte = pte = pte_offset_map(vmf->pmd, faddr); |
| 688 | entry = pte_to_swp_entry(*pte); |
| 689 | if ((unlikely(non_swap_entry(entry)))) { |
| 690 | pte_unmap(orig_pte); |
| 691 | return; |
| 692 | } |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 693 | |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 694 | fpfn = PFN_DOWN(faddr); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 695 | ra_val = GET_SWAP_RA_VAL(vma); |
| 696 | pfn = PFN_DOWN(SWAP_RA_ADDR(ra_val)); |
| 697 | prev_win = SWAP_RA_WIN(ra_val); |
| 698 | hits = SWAP_RA_HITS(ra_val); |
| 699 | ra_info->win = win = __swapin_nr_pages(pfn, fpfn, hits, |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 700 | max_win, prev_win); |
| 701 | atomic_long_set(&vma->swap_readahead_info, |
| 702 | SWAP_RA_VAL(faddr, win, 0)); |
| 703 | |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 704 | if (win == 1) { |
| 705 | pte_unmap(orig_pte); |
| 706 | return; |
| 707 | } |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 708 | |
| 709 | /* Copy the PTEs because the page table may be unmapped */ |
| 710 | if (fpfn == pfn + 1) |
| 711 | swap_ra_clamp_pfn(vma, faddr, fpfn, fpfn + win, &start, &end); |
| 712 | else if (pfn == fpfn + 1) |
| 713 | swap_ra_clamp_pfn(vma, faddr, fpfn - win + 1, fpfn + 1, |
| 714 | &start, &end); |
| 715 | else { |
| 716 | left = (win - 1) / 2; |
| 717 | swap_ra_clamp_pfn(vma, faddr, fpfn - left, fpfn + win - left, |
| 718 | &start, &end); |
| 719 | } |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 720 | ra_info->nr_pte = end - start; |
| 721 | ra_info->offset = fpfn - start; |
| 722 | pte -= ra_info->offset; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 723 | #ifdef CONFIG_64BIT |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 724 | ra_info->ptes = pte; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 725 | #else |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 726 | tpte = ra_info->ptes; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 727 | for (pfn = start; pfn != end; pfn++) |
| 728 | *tpte++ = *pte++; |
| 729 | #endif |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 730 | pte_unmap(orig_pte); |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 731 | } |
| 732 | |
Colin Ian King | f5c754d | 2018-04-05 16:25:05 -0700 | [diff] [blame] | 733 | static struct page *swap_vma_readahead(swp_entry_t fentry, gfp_t gfp_mask, |
| 734 | struct vm_fault *vmf) |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 735 | { |
| 736 | struct blk_plug plug; |
| 737 | struct vm_area_struct *vma = vmf->vma; |
| 738 | struct page *page; |
| 739 | pte_t *pte, pentry; |
| 740 | swp_entry_t entry; |
| 741 | unsigned int i; |
| 742 | bool page_allocated; |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 743 | struct vma_swap_readahead ra_info = {0,}; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 744 | |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 745 | swap_ra_info(vmf, &ra_info); |
| 746 | if (ra_info.win == 1) |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 747 | goto skip; |
| 748 | |
| 749 | blk_start_plug(&plug); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 750 | for (i = 0, pte = ra_info.ptes; i < ra_info.nr_pte; |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 751 | i++, pte++) { |
| 752 | pentry = *pte; |
| 753 | if (pte_none(pentry)) |
| 754 | continue; |
| 755 | if (pte_present(pentry)) |
| 756 | continue; |
| 757 | entry = pte_to_swp_entry(pentry); |
| 758 | if (unlikely(non_swap_entry(entry))) |
| 759 | continue; |
| 760 | page = __read_swap_cache_async(entry, gfp_mask, vma, |
| 761 | vmf->address, &page_allocated); |
| 762 | if (!page) |
| 763 | continue; |
| 764 | if (page_allocated) { |
| 765 | swap_readpage(page, false); |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 766 | if (i != ra_info.offset) { |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 767 | SetPageReadahead(page); |
| 768 | count_vm_event(SWAP_RA); |
| 769 | } |
| 770 | } |
| 771 | put_page(page); |
| 772 | } |
| 773 | blk_finish_plug(&plug); |
| 774 | lru_add_drain(); |
| 775 | skip: |
| 776 | return read_swap_cache_async(fentry, gfp_mask, vma, vmf->address, |
Minchan Kim | eaf649eb | 2018-04-05 16:23:39 -0700 | [diff] [blame] | 777 | ra_info.win == 1); |
Huang Ying | ec56017 | 2017-09-06 16:24:36 -0700 | [diff] [blame] | 778 | } |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 779 | |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 780 | /** |
| 781 | * swapin_readahead - swap in pages in hope we need them soon |
| 782 | * @entry: swap entry of this memory |
| 783 | * @gfp_mask: memory allocation flags |
| 784 | * @vmf: fault information |
| 785 | * |
| 786 | * Returns the struct page for entry and addr, after queueing swapin. |
| 787 | * |
| 788 | * It's a main entry function for swap readahead. By the configuration, |
| 789 | * it will read ahead blocks by cluster-based(ie, physical disk based) |
| 790 | * or vma-based(ie, virtual address based on faulty address) readahead. |
| 791 | */ |
| 792 | struct page *swapin_readahead(swp_entry_t entry, gfp_t gfp_mask, |
| 793 | struct vm_fault *vmf) |
| 794 | { |
| 795 | return swap_use_vma_readahead() ? |
| 796 | swap_vma_readahead(entry, gfp_mask, vmf) : |
| 797 | swap_cluster_readahead(entry, gfp_mask, vmf); |
| 798 | } |
| 799 | |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 800 | #ifdef CONFIG_SYSFS |
| 801 | static ssize_t vma_ra_enabled_show(struct kobject *kobj, |
| 802 | struct kobj_attribute *attr, char *buf) |
| 803 | { |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 804 | return sprintf(buf, "%s\n", enable_vma_readahead ? "true" : "false"); |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 805 | } |
| 806 | static ssize_t vma_ra_enabled_store(struct kobject *kobj, |
| 807 | struct kobj_attribute *attr, |
| 808 | const char *buf, size_t count) |
| 809 | { |
| 810 | if (!strncmp(buf, "true", 4) || !strncmp(buf, "1", 1)) |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 811 | enable_vma_readahead = true; |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 812 | else if (!strncmp(buf, "false", 5) || !strncmp(buf, "0", 1)) |
Minchan Kim | e9e9b7e | 2018-04-05 16:23:42 -0700 | [diff] [blame] | 813 | enable_vma_readahead = false; |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 814 | else |
| 815 | return -EINVAL; |
| 816 | |
| 817 | return count; |
| 818 | } |
| 819 | static struct kobj_attribute vma_ra_enabled_attr = |
| 820 | __ATTR(vma_ra_enabled, 0644, vma_ra_enabled_show, |
| 821 | vma_ra_enabled_store); |
| 822 | |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 823 | static struct attribute *swap_attrs[] = { |
| 824 | &vma_ra_enabled_attr.attr, |
Huang Ying | d9bfcfd | 2017-09-06 16:24:40 -0700 | [diff] [blame] | 825 | NULL, |
| 826 | }; |
| 827 | |
| 828 | static struct attribute_group swap_attr_group = { |
| 829 | .attrs = swap_attrs, |
| 830 | }; |
| 831 | |
| 832 | static int __init swap_init_sysfs(void) |
| 833 | { |
| 834 | int err; |
| 835 | struct kobject *swap_kobj; |
| 836 | |
| 837 | swap_kobj = kobject_create_and_add("swap", mm_kobj); |
| 838 | if (!swap_kobj) { |
| 839 | pr_err("failed to create swap kobject\n"); |
| 840 | return -ENOMEM; |
| 841 | } |
| 842 | err = sysfs_create_group(swap_kobj, &swap_attr_group); |
| 843 | if (err) { |
| 844 | pr_err("failed to register swap group\n"); |
| 845 | goto delete_obj; |
| 846 | } |
| 847 | return 0; |
| 848 | |
| 849 | delete_obj: |
| 850 | kobject_put(swap_kobj); |
| 851 | return err; |
| 852 | } |
| 853 | subsys_initcall(swap_init_sysfs); |
| 854 | #endif |