Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/mm/swap.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
Simon Arlott | 183ff22 | 2007-10-20 01:27:18 +0200 | [diff] [blame] | 8 | * This file contains the default values for the operation of the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | * Linux VM subsystem. Fine-tuning documentation can be found in |
| 10 | * Documentation/sysctl/vm.txt. |
| 11 | * Started 18.12.91 |
| 12 | * Swap aging added 23.2.95, Stephen Tweedie. |
| 13 | * Buffermem limits added 12.3.98, Rik van Riel. |
| 14 | */ |
| 15 | |
| 16 | #include <linux/mm.h> |
| 17 | #include <linux/sched.h> |
| 18 | #include <linux/kernel_stat.h> |
| 19 | #include <linux/swap.h> |
| 20 | #include <linux/mman.h> |
| 21 | #include <linux/pagemap.h> |
| 22 | #include <linux/pagevec.h> |
| 23 | #include <linux/init.h> |
Paul Gortmaker | b95f1b31 | 2011-10-16 02:01:52 -0400 | [diff] [blame] | 24 | #include <linux/export.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/mm_inline.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 26 | #include <linux/percpu_counter.h> |
| 27 | #include <linux/percpu.h> |
| 28 | #include <linux/cpu.h> |
| 29 | #include <linux/notifier.h> |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 30 | #include <linux/backing-dev.h> |
Balbir Singh | 66e1707 | 2008-02-07 00:13:56 -0800 | [diff] [blame] | 31 | #include <linux/memcontrol.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 32 | #include <linux/gfp.h> |
Kent Overstreet | a27bb33 | 2013-05-07 16:19:08 -0700 | [diff] [blame] | 33 | #include <linux/uio.h> |
Khalid Aziz | 0964208 | 2013-09-11 14:22:20 -0700 | [diff] [blame] | 34 | #include <linux/hugetlb.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | |
Lee Schermerhorn | 64d6519 | 2008-10-18 20:26:52 -0700 | [diff] [blame] | 36 | #include "internal.h" |
| 37 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | /* How many pages do we try to swap or page in/out together? */ |
| 39 | int page_cluster; |
| 40 | |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 41 | static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs); |
Vegard Nossum | f84f9504 | 2008-07-23 21:28:14 -0700 | [diff] [blame] | 42 | static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 43 | static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs); |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 44 | |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 45 | /* |
| 46 | * This path almost never happens for VM activity - pages are normally |
| 47 | * freed via pagevecs. But it gets used by networking. |
| 48 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 49 | static void __page_cache_release(struct page *page) |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 50 | { |
| 51 | if (PageLRU(page)) { |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 52 | struct zone *zone = page_zone(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 53 | struct lruvec *lruvec; |
| 54 | unsigned long flags; |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 55 | |
| 56 | spin_lock_irqsave(&zone->lru_lock, flags); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 57 | lruvec = mem_cgroup_page_lruvec(page, zone); |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 58 | VM_BUG_ON(!PageLRU(page)); |
| 59 | __ClearPageLRU(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 60 | del_page_from_lru_list(page, lruvec, page_off_lru(page)); |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 61 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
| 62 | } |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 63 | } |
| 64 | |
| 65 | static void __put_single_page(struct page *page) |
| 66 | { |
| 67 | __page_cache_release(page); |
Li Hong | fc91668 | 2010-03-05 13:41:54 -0800 | [diff] [blame] | 68 | free_hot_cold_page(page, 0); |
Adrian Bunk | b221385 | 2006-09-25 23:31:02 -0700 | [diff] [blame] | 69 | } |
| 70 | |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 71 | static void __put_compound_page(struct page *page) |
| 72 | { |
| 73 | compound_page_dtor *dtor; |
| 74 | |
| 75 | __page_cache_release(page); |
| 76 | dtor = get_compound_page_dtor(page); |
| 77 | (*dtor)(page); |
| 78 | } |
| 79 | |
Nick Piggin | 8519fb3 | 2006-02-07 12:58:52 -0800 | [diff] [blame] | 80 | static void put_compound_page(struct page *page) |
| 81 | { |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 82 | if (unlikely(PageTail(page))) { |
| 83 | /* __split_huge_page_refcount can run under us */ |
David Rientjes | def52ac | 2014-03-03 15:38:18 -0800 | [diff] [blame] | 84 | struct page *page_head = compound_head(page); |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 85 | |
| 86 | if (likely(page != page_head && |
| 87 | get_page_unless_zero(page_head))) { |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 88 | unsigned long flags; |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 89 | |
| 90 | /* |
| 91 | * THP can not break up slab pages so avoid taking |
| 92 | * compound_lock(). Slab performs non-atomic bit ops |
| 93 | * on page->flags for better performance. In particular |
| 94 | * slab_unlock() in slub used to be a hot path. It is |
| 95 | * still hot on arches that do not support |
| 96 | * this_cpu_cmpxchg_double(). |
| 97 | */ |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 98 | if (PageSlab(page_head) || PageHeadHuge(page_head)) { |
| 99 | if (likely(PageTail(page))) { |
| 100 | /* |
| 101 | * __split_huge_page_refcount |
| 102 | * cannot race here. |
| 103 | */ |
| 104 | VM_BUG_ON(!PageHead(page_head)); |
| 105 | atomic_dec(&page->_mapcount); |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 106 | if (put_page_testzero(page_head)) |
| 107 | VM_BUG_ON(1); |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 108 | if (put_page_testzero(page_head)) |
| 109 | __put_compound_page(page_head); |
| 110 | return; |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 111 | } else |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 112 | /* |
| 113 | * __split_huge_page_refcount |
| 114 | * run before us, "page" was a |
| 115 | * THP tail. The split |
| 116 | * page_head has been freed |
| 117 | * and reallocated as slab or |
| 118 | * hugetlbfs page of smaller |
| 119 | * order (only possible if |
| 120 | * reallocated as slab on |
| 121 | * x86). |
| 122 | */ |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 123 | goto skip_lock; |
| 124 | } |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 125 | /* |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 126 | * page_head wasn't a dangling pointer but it |
| 127 | * may not be a head page anymore by the time |
| 128 | * we obtain the lock. That is ok as long as it |
| 129 | * can't be freed from under us. |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 130 | */ |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 131 | flags = compound_lock_irqsave(page_head); |
| 132 | if (unlikely(!PageTail(page))) { |
| 133 | /* __split_huge_page_refcount run before us */ |
| 134 | compound_unlock_irqrestore(page_head, flags); |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 135 | skip_lock: |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 136 | if (put_page_testzero(page_head)) { |
| 137 | /* |
| 138 | * The head page may have been |
| 139 | * freed and reallocated as a |
| 140 | * compound page of smaller |
| 141 | * order and then freed again. |
| 142 | * All we know is that it |
| 143 | * cannot have become: a THP |
| 144 | * page, a compound page of |
| 145 | * higher order, a tail page. |
| 146 | * That is because we still |
| 147 | * hold the refcount of the |
| 148 | * split THP tail and |
| 149 | * page_head was the THP head |
| 150 | * before the split. |
| 151 | */ |
| 152 | if (PageHead(page_head)) |
| 153 | __put_compound_page(page_head); |
| 154 | else |
| 155 | __put_single_page(page_head); |
| 156 | } |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 157 | out_put_single: |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 158 | if (put_page_testzero(page)) |
| 159 | __put_single_page(page); |
| 160 | return; |
| 161 | } |
| 162 | VM_BUG_ON(page_head != page->first_page); |
| 163 | /* |
| 164 | * We can release the refcount taken by |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 165 | * get_page_unless_zero() now that |
| 166 | * __split_huge_page_refcount() is blocked on |
| 167 | * the compound_lock. |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 168 | */ |
| 169 | if (put_page_testzero(page_head)) |
| 170 | VM_BUG_ON(1); |
| 171 | /* __split_huge_page_refcount will wait now */ |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 172 | VM_BUG_ON(page_mapcount(page) <= 0); |
| 173 | atomic_dec(&page->_mapcount); |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 174 | VM_BUG_ON(atomic_read(&page_head->_count) <= 0); |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 175 | VM_BUG_ON(atomic_read(&page->_count) != 0); |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 176 | compound_unlock_irqrestore(page_head, flags); |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 177 | |
Andrea Arcangeli | a95a82e | 2011-01-13 15:46:33 -0800 | [diff] [blame] | 178 | if (put_page_testzero(page_head)) { |
| 179 | if (PageHead(page_head)) |
| 180 | __put_compound_page(page_head); |
| 181 | else |
| 182 | __put_single_page(page_head); |
| 183 | } |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 184 | } else { |
| 185 | /* page_head is a dangling pointer */ |
| 186 | VM_BUG_ON(PageTail(page)); |
| 187 | goto out_put_single; |
| 188 | } |
| 189 | } else if (put_page_testzero(page)) { |
| 190 | if (PageHead(page)) |
| 191 | __put_compound_page(page); |
| 192 | else |
| 193 | __put_single_page(page); |
Nick Piggin | 8519fb3 | 2006-02-07 12:58:52 -0800 | [diff] [blame] | 194 | } |
| 195 | } |
| 196 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | void put_page(struct page *page) |
| 198 | { |
Nick Piggin | 8519fb3 | 2006-02-07 12:58:52 -0800 | [diff] [blame] | 199 | if (unlikely(PageCompound(page))) |
| 200 | put_compound_page(page); |
| 201 | else if (put_page_testzero(page)) |
Andrea Arcangeli | 9180706 | 2011-01-13 15:46:32 -0800 | [diff] [blame] | 202 | __put_single_page(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | } |
| 204 | EXPORT_SYMBOL(put_page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 206 | /* |
| 207 | * This function is exported but must not be called by anything other |
| 208 | * than get_page(). It implements the slow path of get_page(). |
| 209 | */ |
| 210 | bool __get_page_tail(struct page *page) |
| 211 | { |
| 212 | /* |
| 213 | * This takes care of get_page() if run on a tail page |
| 214 | * returned by one of the get_user_pages/follow_page variants. |
| 215 | * get_user_pages/follow_page itself doesn't need the compound |
| 216 | * lock because it runs __get_page_tail_foll() under the |
| 217 | * proper PT lock that already serializes against |
| 218 | * split_huge_page(). |
| 219 | */ |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 220 | unsigned long flags; |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 221 | bool got = false; |
David Rientjes | def52ac | 2014-03-03 15:38:18 -0800 | [diff] [blame] | 222 | struct page *page_head = compound_head(page); |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 223 | |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 224 | if (likely(page != page_head && get_page_unless_zero(page_head))) { |
| 225 | /* Ref to put_compound_page() comment. */ |
| 226 | if (PageSlab(page_head) || PageHeadHuge(page_head)) { |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 227 | if (likely(PageTail(page))) { |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 228 | /* |
| 229 | * This is a hugetlbfs page or a slab |
| 230 | * page. __split_huge_page_refcount |
| 231 | * cannot race here. |
| 232 | */ |
| 233 | VM_BUG_ON(!PageHead(page_head)); |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 234 | __get_page_tail_foll(page, false); |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 235 | return true; |
| 236 | } else { |
| 237 | /* |
| 238 | * __split_huge_page_refcount run |
| 239 | * before us, "page" was a THP |
| 240 | * tail. The split page_head has been |
| 241 | * freed and reallocated as slab or |
| 242 | * hugetlbfs page of smaller order |
| 243 | * (only possible if reallocated as |
| 244 | * slab on x86). |
| 245 | */ |
Khalid Aziz | 0964208 | 2013-09-11 14:22:20 -0700 | [diff] [blame] | 246 | put_page(page_head); |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 247 | return false; |
| 248 | } |
Pravin B Shelar | 5bf5f03 | 2012-05-29 15:06:49 -0700 | [diff] [blame] | 249 | } |
Andrea Arcangeli | 17b6ada | 2013-11-21 14:32:02 -0800 | [diff] [blame] | 250 | |
| 251 | /* |
| 252 | * page_head wasn't a dangling pointer but it |
| 253 | * may not be a head page anymore by the time |
| 254 | * we obtain the lock. That is ok as long as it |
| 255 | * can't be freed from under us. |
| 256 | */ |
| 257 | flags = compound_lock_irqsave(page_head); |
| 258 | /* here __split_huge_page_refcount won't run anymore */ |
| 259 | if (likely(PageTail(page))) { |
| 260 | __get_page_tail_foll(page, false); |
| 261 | got = true; |
| 262 | } |
| 263 | compound_unlock_irqrestore(page_head, flags); |
| 264 | if (unlikely(!got)) |
| 265 | put_page(page_head); |
Andrea Arcangeli | 70b50f9 | 2011-11-02 13:36:59 -0700 | [diff] [blame] | 266 | } |
| 267 | return got; |
| 268 | } |
| 269 | EXPORT_SYMBOL(__get_page_tail); |
| 270 | |
Alexander Zarochentsev | 1d7ea73 | 2006-08-13 23:24:27 -0700 | [diff] [blame] | 271 | /** |
Randy Dunlap | 7682486 | 2008-03-19 17:00:40 -0700 | [diff] [blame] | 272 | * put_pages_list() - release a list of pages |
| 273 | * @pages: list of pages threaded on page->lru |
Alexander Zarochentsev | 1d7ea73 | 2006-08-13 23:24:27 -0700 | [diff] [blame] | 274 | * |
| 275 | * Release a list of pages which are strung together on page.lru. Currently |
| 276 | * used by read_cache_pages() and related error recovery code. |
Alexander Zarochentsev | 1d7ea73 | 2006-08-13 23:24:27 -0700 | [diff] [blame] | 277 | */ |
| 278 | void put_pages_list(struct list_head *pages) |
| 279 | { |
| 280 | while (!list_empty(pages)) { |
| 281 | struct page *victim; |
| 282 | |
| 283 | victim = list_entry(pages->prev, struct page, lru); |
| 284 | list_del(&victim->lru); |
| 285 | page_cache_release(victim); |
| 286 | } |
| 287 | } |
| 288 | EXPORT_SYMBOL(put_pages_list); |
| 289 | |
Mel Gorman | 18022c5 | 2012-07-31 16:44:51 -0700 | [diff] [blame] | 290 | /* |
| 291 | * get_kernel_pages() - pin kernel pages in memory |
| 292 | * @kiov: An array of struct kvec structures |
| 293 | * @nr_segs: number of segments to pin |
| 294 | * @write: pinning for read/write, currently ignored |
| 295 | * @pages: array that receives pointers to the pages pinned. |
| 296 | * Should be at least nr_segs long. |
| 297 | * |
| 298 | * Returns number of pages pinned. This may be fewer than the number |
| 299 | * requested. If nr_pages is 0 or negative, returns 0. If no pages |
| 300 | * were pinned, returns -errno. Each page returned must be released |
| 301 | * with a put_page() call when it is finished with. |
| 302 | */ |
| 303 | int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write, |
| 304 | struct page **pages) |
| 305 | { |
| 306 | int seg; |
| 307 | |
| 308 | for (seg = 0; seg < nr_segs; seg++) { |
| 309 | if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE)) |
| 310 | return seg; |
| 311 | |
Mel Gorman | 5a17811 | 2012-07-31 16:45:02 -0700 | [diff] [blame] | 312 | pages[seg] = kmap_to_page(kiov[seg].iov_base); |
Mel Gorman | 18022c5 | 2012-07-31 16:44:51 -0700 | [diff] [blame] | 313 | page_cache_get(pages[seg]); |
| 314 | } |
| 315 | |
| 316 | return seg; |
| 317 | } |
| 318 | EXPORT_SYMBOL_GPL(get_kernel_pages); |
| 319 | |
| 320 | /* |
| 321 | * get_kernel_page() - pin a kernel page in memory |
| 322 | * @start: starting kernel address |
| 323 | * @write: pinning for read/write, currently ignored |
| 324 | * @pages: array that receives pointer to the page pinned. |
| 325 | * Must be at least nr_segs long. |
| 326 | * |
| 327 | * Returns 1 if page is pinned. If the page was not pinned, returns |
| 328 | * -errno. The page returned must be released with a put_page() call |
| 329 | * when it is finished with. |
| 330 | */ |
| 331 | int get_kernel_page(unsigned long start, int write, struct page **pages) |
| 332 | { |
| 333 | const struct kvec kiov = { |
| 334 | .iov_base = (void *)start, |
| 335 | .iov_len = PAGE_SIZE |
| 336 | }; |
| 337 | |
| 338 | return get_kernel_pages(&kiov, 1, write, pages); |
| 339 | } |
| 340 | EXPORT_SYMBOL_GPL(get_kernel_page); |
| 341 | |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 342 | static void pagevec_lru_move_fn(struct pagevec *pvec, |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 343 | void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg), |
| 344 | void *arg) |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 345 | { |
| 346 | int i; |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 347 | struct zone *zone = NULL; |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 348 | struct lruvec *lruvec; |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 349 | unsigned long flags = 0; |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 350 | |
| 351 | for (i = 0; i < pagevec_count(pvec); i++) { |
| 352 | struct page *page = pvec->pages[i]; |
| 353 | struct zone *pagezone = page_zone(page); |
| 354 | |
| 355 | if (pagezone != zone) { |
| 356 | if (zone) |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 357 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 358 | zone = pagezone; |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 359 | spin_lock_irqsave(&zone->lru_lock, flags); |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 360 | } |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 361 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 362 | lruvec = mem_cgroup_page_lruvec(page, zone); |
| 363 | (*move_fn)(page, lruvec, arg); |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 364 | } |
| 365 | if (zone) |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 366 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
Linus Torvalds | 83896fb | 2011-01-17 14:42:34 -0800 | [diff] [blame] | 367 | release_pages(pvec->pages, pvec->nr, pvec->cold); |
| 368 | pagevec_reinit(pvec); |
Shaohua Li | d8505de | 2011-01-13 15:47:33 -0800 | [diff] [blame] | 369 | } |
| 370 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 371 | static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec, |
| 372 | void *arg) |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 373 | { |
| 374 | int *pgmoved = arg; |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 375 | |
| 376 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
| 377 | enum lru_list lru = page_lru_base_type(page); |
Johannes Weiner | 925b767 | 2012-01-12 17:18:15 -0800 | [diff] [blame] | 378 | list_move_tail(&page->lru, &lruvec->lists[lru]); |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 379 | (*pgmoved)++; |
| 380 | } |
| 381 | } |
| 382 | |
| 383 | /* |
| 384 | * pagevec_move_tail() must be called with IRQ disabled. |
| 385 | * Otherwise this may cause nasty races. |
| 386 | */ |
| 387 | static void pagevec_move_tail(struct pagevec *pvec) |
| 388 | { |
| 389 | int pgmoved = 0; |
| 390 | |
| 391 | pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved); |
| 392 | __count_vm_events(PGROTATED, pgmoved); |
| 393 | } |
| 394 | |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 395 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | * Writeback is about to end against a page which has been marked for immediate |
| 397 | * reclaim. If it still appears to be reclaimable, move it to the tail of the |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 398 | * inactive list. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 399 | */ |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 400 | void rotate_reclaimable_page(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | { |
Miklos Szeredi | ac6aadb | 2008-04-28 02:12:38 -0700 | [diff] [blame] | 402 | if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) && |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 403 | !PageUnevictable(page) && PageLRU(page)) { |
Miklos Szeredi | ac6aadb | 2008-04-28 02:12:38 -0700 | [diff] [blame] | 404 | struct pagevec *pvec; |
| 405 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 406 | |
Miklos Szeredi | ac6aadb | 2008-04-28 02:12:38 -0700 | [diff] [blame] | 407 | page_cache_get(page); |
| 408 | local_irq_save(flags); |
| 409 | pvec = &__get_cpu_var(lru_rotate_pvecs); |
| 410 | if (!pagevec_add(pvec, page)) |
| 411 | pagevec_move_tail(pvec); |
| 412 | local_irq_restore(flags); |
| 413 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 414 | } |
| 415 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 416 | static void update_page_reclaim_stat(struct lruvec *lruvec, |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 417 | int file, int rotated) |
| 418 | { |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 419 | struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 420 | |
| 421 | reclaim_stat->recent_scanned[file]++; |
| 422 | if (rotated) |
| 423 | reclaim_stat->recent_rotated[file]++; |
KOSAKI Motohiro | 3e2f41f | 2009-01-07 18:08:20 -0800 | [diff] [blame] | 424 | } |
| 425 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 426 | static void __activate_page(struct page *page, struct lruvec *lruvec, |
| 427 | void *arg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | { |
Linus Torvalds | 7a60857 | 2011-01-17 14:42:19 -0800 | [diff] [blame] | 429 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
| 430 | int file = page_is_file_cache(page); |
| 431 | int lru = page_lru_base_type(page); |
Linus Torvalds | 7a60857 | 2011-01-17 14:42:19 -0800 | [diff] [blame] | 432 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 433 | del_page_from_lru_list(page, lruvec, lru); |
Linus Torvalds | 7a60857 | 2011-01-17 14:42:19 -0800 | [diff] [blame] | 434 | SetPageActive(page); |
| 435 | lru += LRU_ACTIVE; |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 436 | add_page_to_lru_list(page, lruvec, lru); |
Linus Torvalds | 7a60857 | 2011-01-17 14:42:19 -0800 | [diff] [blame] | 437 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 438 | __count_vm_event(PGACTIVATE); |
| 439 | update_page_reclaim_stat(lruvec, file, 1); |
Linus Torvalds | 7a60857 | 2011-01-17 14:42:19 -0800 | [diff] [blame] | 440 | } |
Shaohua Li | eb709b0 | 2011-05-24 17:12:55 -0700 | [diff] [blame] | 441 | } |
| 442 | |
| 443 | #ifdef CONFIG_SMP |
| 444 | static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs); |
| 445 | |
| 446 | static void activate_page_drain(int cpu) |
| 447 | { |
| 448 | struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu); |
| 449 | |
| 450 | if (pagevec_count(pvec)) |
| 451 | pagevec_lru_move_fn(pvec, __activate_page, NULL); |
| 452 | } |
| 453 | |
| 454 | void activate_page(struct page *page) |
| 455 | { |
| 456 | if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
| 457 | struct pagevec *pvec = &get_cpu_var(activate_page_pvecs); |
| 458 | |
| 459 | page_cache_get(page); |
| 460 | if (!pagevec_add(pvec, page)) |
| 461 | pagevec_lru_move_fn(pvec, __activate_page, NULL); |
| 462 | put_cpu_var(activate_page_pvecs); |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | #else |
| 467 | static inline void activate_page_drain(int cpu) |
| 468 | { |
| 469 | } |
| 470 | |
| 471 | void activate_page(struct page *page) |
| 472 | { |
| 473 | struct zone *zone = page_zone(page); |
| 474 | |
| 475 | spin_lock_irq(&zone->lru_lock); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 476 | __activate_page(page, mem_cgroup_page_lruvec(page, zone), NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 477 | spin_unlock_irq(&zone->lru_lock); |
| 478 | } |
Shaohua Li | eb709b0 | 2011-05-24 17:12:55 -0700 | [diff] [blame] | 479 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 480 | |
| 481 | /* |
| 482 | * Mark a page as having seen activity. |
| 483 | * |
| 484 | * inactive,unreferenced -> inactive,referenced |
| 485 | * inactive,referenced -> active,unreferenced |
| 486 | * active,unreferenced -> active,referenced |
| 487 | */ |
Harvey Harrison | 920c7a5 | 2008-02-04 22:29:26 -0800 | [diff] [blame] | 488 | void mark_page_accessed(struct page *page) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 490 | if (!PageActive(page) && !PageUnevictable(page) && |
| 491 | PageReferenced(page) && PageLRU(page)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | activate_page(page); |
| 493 | ClearPageReferenced(page); |
| 494 | } else if (!PageReferenced(page)) { |
| 495 | SetPageReferenced(page); |
| 496 | } |
| 497 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 498 | EXPORT_SYMBOL(mark_page_accessed); |
| 499 | |
Robin Dong | d741c9c | 2012-10-08 16:29:05 -0700 | [diff] [blame] | 500 | /* |
| 501 | * Order of operations is important: flush the pagevec when it's already |
| 502 | * full, not when adding the last page, to make sure that last page is |
| 503 | * not added to the LRU directly when passed to this function. Because |
| 504 | * mark_page_accessed() (called after this when writing) only activates |
| 505 | * pages that are on the LRU, linear writes in subpage chunks would see |
| 506 | * every PAGEVEC_SIZE page activated, which is unexpected. |
| 507 | */ |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 508 | void __lru_cache_add(struct page *page, enum lru_list lru) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 509 | { |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 510 | struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 511 | |
| 512 | page_cache_get(page); |
Robin Dong | d741c9c | 2012-10-08 16:29:05 -0700 | [diff] [blame] | 513 | if (!pagevec_space(pvec)) |
Hugh Dickins | 5095ae83 | 2012-01-12 17:19:58 -0800 | [diff] [blame] | 514 | __pagevec_lru_add(pvec, lru); |
Robin Dong | d741c9c | 2012-10-08 16:29:05 -0700 | [diff] [blame] | 515 | pagevec_add(pvec, page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 516 | put_cpu_var(lru_add_pvecs); |
| 517 | } |
Miklos Szeredi | 47846b0 | 2010-05-25 15:06:06 +0200 | [diff] [blame] | 518 | EXPORT_SYMBOL(__lru_cache_add); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 519 | |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 520 | /** |
| 521 | * lru_cache_add_lru - add a page to a page list |
| 522 | * @page: the page to be added to the LRU. |
| 523 | * @lru: the LRU list to which the page is added. |
| 524 | */ |
| 525 | void lru_cache_add_lru(struct page *page, enum lru_list lru) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 526 | { |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 527 | if (PageActive(page)) { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 528 | VM_BUG_ON(PageUnevictable(page)); |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 529 | ClearPageActive(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 530 | } else if (PageUnevictable(page)) { |
| 531 | VM_BUG_ON(PageActive(page)); |
| 532 | ClearPageUnevictable(page); |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 533 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 534 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 535 | VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page)); |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 536 | __lru_cache_add(page, lru); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | } |
| 538 | |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 539 | /** |
| 540 | * add_page_to_unevictable_list - add a page to the unevictable list |
| 541 | * @page: the page to be added to the unevictable list |
| 542 | * |
| 543 | * Add page directly to its zone's unevictable list. To avoid races with |
| 544 | * tasks that might be making the page evictable, through eg. munlock, |
| 545 | * munmap or exit, while it's not on the lru, we want to add the page |
| 546 | * while it's locked or otherwise "invisible" to other tasks. This is |
| 547 | * difficult to do when using the pagevec cache, so bypass that. |
| 548 | */ |
| 549 | void add_page_to_unevictable_list(struct page *page) |
| 550 | { |
| 551 | struct zone *zone = page_zone(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 552 | struct lruvec *lruvec; |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 553 | |
| 554 | spin_lock_irq(&zone->lru_lock); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 555 | lruvec = mem_cgroup_page_lruvec(page, zone); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 556 | SetPageUnevictable(page); |
| 557 | SetPageLRU(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 558 | add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 559 | spin_unlock_irq(&zone->lru_lock); |
| 560 | } |
| 561 | |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 562 | /* |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 563 | * If the page can not be invalidated, it is moved to the |
| 564 | * inactive list to speed up its reclaim. It is moved to the |
| 565 | * head of the list, rather than the tail, to give the flusher |
| 566 | * threads some time to write it out, as this is much more |
| 567 | * effective than the single-page writeout from reclaim. |
Minchan Kim | 278df9f | 2011-03-22 16:32:54 -0700 | [diff] [blame] | 568 | * |
| 569 | * If the page isn't page_mapped and dirty/writeback, the page |
| 570 | * could reclaim asap using PG_reclaim. |
| 571 | * |
| 572 | * 1. active, mapped page -> none |
| 573 | * 2. active, dirty/writeback page -> inactive, head, PG_reclaim |
| 574 | * 3. inactive, mapped page -> none |
| 575 | * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim |
| 576 | * 5. inactive, clean -> inactive, tail |
| 577 | * 6. Others -> none |
| 578 | * |
| 579 | * In 4, why it moves inactive's head, the VM expects the page would |
| 580 | * be write it out by flusher threads as this is much more effective |
| 581 | * than the single-page writeout from reclaim. |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 582 | */ |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 583 | static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec, |
| 584 | void *arg) |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 585 | { |
| 586 | int lru, file; |
Minchan Kim | 278df9f | 2011-03-22 16:32:54 -0700 | [diff] [blame] | 587 | bool active; |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 588 | |
Minchan Kim | 278df9f | 2011-03-22 16:32:54 -0700 | [diff] [blame] | 589 | if (!PageLRU(page)) |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 590 | return; |
| 591 | |
Minchan Kim | bad49d9 | 2011-05-11 15:13:30 -0700 | [diff] [blame] | 592 | if (PageUnevictable(page)) |
| 593 | return; |
| 594 | |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 595 | /* Some processes are using the page */ |
| 596 | if (page_mapped(page)) |
| 597 | return; |
| 598 | |
Minchan Kim | 278df9f | 2011-03-22 16:32:54 -0700 | [diff] [blame] | 599 | active = PageActive(page); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 600 | file = page_is_file_cache(page); |
| 601 | lru = page_lru_base_type(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 602 | |
| 603 | del_page_from_lru_list(page, lruvec, lru + active); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 604 | ClearPageActive(page); |
| 605 | ClearPageReferenced(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 606 | add_page_to_lru_list(page, lruvec, lru); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 607 | |
Minchan Kim | 278df9f | 2011-03-22 16:32:54 -0700 | [diff] [blame] | 608 | if (PageWriteback(page) || PageDirty(page)) { |
| 609 | /* |
| 610 | * PG_reclaim could be raced with end_page_writeback |
| 611 | * It can make readahead confusing. But race window |
| 612 | * is _really_ small and it's non-critical problem. |
| 613 | */ |
| 614 | SetPageReclaim(page); |
| 615 | } else { |
| 616 | /* |
| 617 | * The page's writeback ends up during pagevec |
| 618 | * We moves tha page into tail of inactive. |
| 619 | */ |
Johannes Weiner | 925b767 | 2012-01-12 17:18:15 -0800 | [diff] [blame] | 620 | list_move_tail(&page->lru, &lruvec->lists[lru]); |
Minchan Kim | 278df9f | 2011-03-22 16:32:54 -0700 | [diff] [blame] | 621 | __count_vm_event(PGROTATED); |
| 622 | } |
| 623 | |
| 624 | if (active) |
| 625 | __count_vm_event(PGDEACTIVATE); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 626 | update_page_reclaim_stat(lruvec, file, 0); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 627 | } |
| 628 | |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 629 | /* |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 630 | * Drain pages out of the cpu's pagevecs. |
| 631 | * Either "cpu" is the current CPU, and preemption has already been |
| 632 | * disabled; or "cpu" is being hot-unplugged, and is already dead. |
| 633 | */ |
Konstantin Khlebnikov | f0cb3c7 | 2012-03-21 16:34:06 -0700 | [diff] [blame] | 634 | void lru_add_drain_cpu(int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | { |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 636 | struct pagevec *pvecs = per_cpu(lru_add_pvecs, cpu); |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 637 | struct pagevec *pvec; |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 638 | int lru; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 639 | |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 640 | for_each_lru(lru) { |
| 641 | pvec = &pvecs[lru - LRU_BASE]; |
| 642 | if (pagevec_count(pvec)) |
Hugh Dickins | 5095ae83 | 2012-01-12 17:19:58 -0800 | [diff] [blame] | 643 | __pagevec_lru_add(pvec, lru); |
KOSAKI Motohiro | f04e9eb | 2008-10-18 20:26:19 -0700 | [diff] [blame] | 644 | } |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 645 | |
| 646 | pvec = &per_cpu(lru_rotate_pvecs, cpu); |
| 647 | if (pagevec_count(pvec)) { |
| 648 | unsigned long flags; |
| 649 | |
| 650 | /* No harm done if a racing interrupt already did this */ |
| 651 | local_irq_save(flags); |
| 652 | pagevec_move_tail(pvec); |
| 653 | local_irq_restore(flags); |
| 654 | } |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 655 | |
| 656 | pvec = &per_cpu(lru_deactivate_pvecs, cpu); |
| 657 | if (pagevec_count(pvec)) |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 658 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
Shaohua Li | eb709b0 | 2011-05-24 17:12:55 -0700 | [diff] [blame] | 659 | |
| 660 | activate_page_drain(cpu); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 661 | } |
| 662 | |
| 663 | /** |
| 664 | * deactivate_page - forcefully deactivate a page |
| 665 | * @page: page to deactivate |
| 666 | * |
| 667 | * This function hints the VM that @page is a good reclaim candidate, |
| 668 | * for example if its invalidation fails due to the page being dirty |
| 669 | * or under writeback. |
| 670 | */ |
| 671 | void deactivate_page(struct page *page) |
| 672 | { |
Minchan Kim | 821ed6b | 2011-05-24 17:12:31 -0700 | [diff] [blame] | 673 | /* |
| 674 | * In a workload with many unevictable page such as mprotect, unevictable |
| 675 | * page deactivation for accelerating reclaim is pointless. |
| 676 | */ |
| 677 | if (PageUnevictable(page)) |
| 678 | return; |
| 679 | |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 680 | if (likely(get_page_unless_zero(page))) { |
| 681 | struct pagevec *pvec = &get_cpu_var(lru_deactivate_pvecs); |
| 682 | |
| 683 | if (!pagevec_add(pvec, page)) |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 684 | pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
Minchan Kim | 3156018 | 2011-03-22 16:32:52 -0700 | [diff] [blame] | 685 | put_cpu_var(lru_deactivate_pvecs); |
| 686 | } |
Andrew Morton | 80bfed9 | 2006-01-06 00:11:14 -0800 | [diff] [blame] | 687 | } |
| 688 | |
| 689 | void lru_add_drain(void) |
| 690 | { |
Konstantin Khlebnikov | f0cb3c7 | 2012-03-21 16:34:06 -0700 | [diff] [blame] | 691 | lru_add_drain_cpu(get_cpu()); |
Andrew Morton | 80bfed9 | 2006-01-06 00:11:14 -0800 | [diff] [blame] | 692 | put_cpu(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 693 | } |
| 694 | |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 695 | static void lru_add_drain_per_cpu(struct work_struct *dummy) |
Nick Piggin | 053837f | 2006-01-18 17:42:27 -0800 | [diff] [blame] | 696 | { |
| 697 | lru_add_drain(); |
| 698 | } |
| 699 | |
| 700 | /* |
| 701 | * Returns 0 for success |
| 702 | */ |
| 703 | int lru_add_drain_all(void) |
| 704 | { |
David Howells | c402895 | 2006-11-22 14:57:56 +0000 | [diff] [blame] | 705 | return schedule_on_each_cpu(lru_add_drain_per_cpu); |
Nick Piggin | 053837f | 2006-01-18 17:42:27 -0800 | [diff] [blame] | 706 | } |
| 707 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 708 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 709 | * Batched page_cache_release(). Decrement the reference count on all the |
| 710 | * passed pages. If it fell to zero then remove the page from the LRU and |
| 711 | * free it. |
| 712 | * |
| 713 | * Avoid taking zone->lru_lock if possible, but if it is taken, retain it |
| 714 | * for the remainder of the operation. |
| 715 | * |
Fernando Luis Vazquez Cao | ab33dc0 | 2008-07-29 22:33:40 -0700 | [diff] [blame] | 716 | * The locking in this function is against shrink_inactive_list(): we recheck |
| 717 | * the page count inside the lock to see whether shrink_inactive_list() |
| 718 | * grabbed the page via the LRU. If it did, give up: shrink_inactive_list() |
| 719 | * will free it. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 720 | */ |
| 721 | void release_pages(struct page **pages, int nr, int cold) |
| 722 | { |
| 723 | int i; |
Konstantin Khlebnikov | cc59850 | 2012-01-10 15:07:04 -0800 | [diff] [blame] | 724 | LIST_HEAD(pages_to_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 725 | struct zone *zone = NULL; |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 726 | struct lruvec *lruvec; |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 727 | unsigned long uninitialized_var(flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 728 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 729 | for (i = 0; i < nr; i++) { |
| 730 | struct page *page = pages[i]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 731 | |
Nick Piggin | 8519fb3 | 2006-02-07 12:58:52 -0800 | [diff] [blame] | 732 | if (unlikely(PageCompound(page))) { |
| 733 | if (zone) { |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 734 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
Nick Piggin | 8519fb3 | 2006-02-07 12:58:52 -0800 | [diff] [blame] | 735 | zone = NULL; |
| 736 | } |
| 737 | put_compound_page(page); |
| 738 | continue; |
| 739 | } |
| 740 | |
Nick Piggin | b581003 | 2005-10-29 18:16:12 -0700 | [diff] [blame] | 741 | if (!put_page_testzero(page)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 742 | continue; |
| 743 | |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 744 | if (PageLRU(page)) { |
| 745 | struct zone *pagezone = page_zone(page); |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 746 | |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 747 | if (pagezone != zone) { |
| 748 | if (zone) |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 749 | spin_unlock_irqrestore(&zone->lru_lock, |
| 750 | flags); |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 751 | zone = pagezone; |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 752 | spin_lock_irqsave(&zone->lru_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 753 | } |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 754 | |
| 755 | lruvec = mem_cgroup_page_lruvec(page, zone); |
Nick Piggin | 725d704 | 2006-09-25 23:30:55 -0700 | [diff] [blame] | 756 | VM_BUG_ON(!PageLRU(page)); |
Nick Piggin | 6745391 | 2006-03-22 00:08:00 -0800 | [diff] [blame] | 757 | __ClearPageLRU(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 758 | del_page_from_lru_list(page, lruvec, page_off_lru(page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 759 | } |
Nick Piggin | 46453a6 | 2006-03-22 00:07:58 -0800 | [diff] [blame] | 760 | |
Konstantin Khlebnikov | cc59850 | 2012-01-10 15:07:04 -0800 | [diff] [blame] | 761 | list_add(&page->lru, &pages_to_free); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 762 | } |
| 763 | if (zone) |
Hisashi Hifumi | 902aaed | 2007-10-16 01:24:52 -0700 | [diff] [blame] | 764 | spin_unlock_irqrestore(&zone->lru_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 765 | |
Konstantin Khlebnikov | cc59850 | 2012-01-10 15:07:04 -0800 | [diff] [blame] | 766 | free_hot_cold_page_list(&pages_to_free, cold); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 767 | } |
Miklos Szeredi | 0be8557 | 2010-10-27 15:34:46 -0700 | [diff] [blame] | 768 | EXPORT_SYMBOL(release_pages); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 769 | |
| 770 | /* |
| 771 | * The pages which we're about to release may be in the deferred lru-addition |
| 772 | * queues. That would prevent them from really being freed right now. That's |
| 773 | * OK from a correctness point of view but is inefficient - those pages may be |
| 774 | * cache-warm and we want to give them back to the page allocator ASAP. |
| 775 | * |
| 776 | * So __pagevec_release() will drain those queues here. __pagevec_lru_add() |
| 777 | * and __pagevec_lru_add_active() call release_pages() directly to avoid |
| 778 | * mutual recursion. |
| 779 | */ |
| 780 | void __pagevec_release(struct pagevec *pvec) |
| 781 | { |
| 782 | lru_add_drain(); |
| 783 | release_pages(pvec->pages, pagevec_count(pvec), pvec->cold); |
| 784 | pagevec_reinit(pvec); |
| 785 | } |
Steve French | 7f28570 | 2005-11-01 10:22:55 -0800 | [diff] [blame] | 786 | EXPORT_SYMBOL(__pagevec_release); |
| 787 | |
Hugh Dickins | 12d2710 | 2012-01-12 17:19:52 -0800 | [diff] [blame] | 788 | #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 789 | /* used by __split_huge_page_refcount() */ |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 790 | void lru_add_page_tail(struct page *page, struct page *page_tail, |
Shaohua Li | 5bc7b8a | 2013-04-29 15:08:36 -0700 | [diff] [blame] | 791 | struct lruvec *lruvec, struct list_head *list) |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 792 | { |
Hugh Dickins | 7512102 | 2012-03-05 14:59:18 -0800 | [diff] [blame] | 793 | int uninitialized_var(active); |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 794 | enum lru_list lru; |
| 795 | const int file = 0; |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 796 | |
| 797 | VM_BUG_ON(!PageHead(page)); |
| 798 | VM_BUG_ON(PageCompound(page_tail)); |
| 799 | VM_BUG_ON(PageLRU(page_tail)); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 800 | VM_BUG_ON(NR_CPUS != 1 && |
| 801 | !spin_is_locked(&lruvec_zone(lruvec)->lru_lock)); |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 802 | |
Shaohua Li | 5bc7b8a | 2013-04-29 15:08:36 -0700 | [diff] [blame] | 803 | if (!list) |
| 804 | SetPageLRU(page_tail); |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 805 | |
Hugh Dickins | 39b5f29 | 2012-10-08 16:33:18 -0700 | [diff] [blame] | 806 | if (page_evictable(page_tail)) { |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 807 | if (PageActive(page)) { |
| 808 | SetPageActive(page_tail); |
| 809 | active = 1; |
| 810 | lru = LRU_ACTIVE_ANON; |
| 811 | } else { |
| 812 | active = 0; |
| 813 | lru = LRU_INACTIVE_ANON; |
| 814 | } |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 815 | } else { |
| 816 | SetPageUnevictable(page_tail); |
Hugh Dickins | 12d2710 | 2012-01-12 17:19:52 -0800 | [diff] [blame] | 817 | lru = LRU_UNEVICTABLE; |
| 818 | } |
| 819 | |
| 820 | if (likely(PageLRU(page))) |
| 821 | list_add_tail(&page_tail->lru, &page->lru); |
Shaohua Li | 5bc7b8a | 2013-04-29 15:08:36 -0700 | [diff] [blame] | 822 | else if (list) { |
| 823 | /* page reclaim is reclaiming a huge page */ |
| 824 | get_page(page_tail); |
| 825 | list_add_tail(&page_tail->lru, list); |
| 826 | } else { |
Hugh Dickins | 12d2710 | 2012-01-12 17:19:52 -0800 | [diff] [blame] | 827 | struct list_head *list_head; |
| 828 | /* |
| 829 | * Head page has not yet been counted, as an hpage, |
| 830 | * so we must account for each subpage individually. |
| 831 | * |
| 832 | * Use the standard add function to put page_tail on the list, |
| 833 | * but then correct its position so they all end up in order. |
| 834 | */ |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 835 | add_page_to_lru_list(page_tail, lruvec, lru); |
Hugh Dickins | 12d2710 | 2012-01-12 17:19:52 -0800 | [diff] [blame] | 836 | list_head = page_tail->lru.prev; |
| 837 | list_move_tail(&page_tail->lru, list_head); |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 838 | } |
Hugh Dickins | 7512102 | 2012-03-05 14:59:18 -0800 | [diff] [blame] | 839 | |
| 840 | if (!PageUnevictable(page)) |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 841 | update_page_reclaim_stat(lruvec, file, active); |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 842 | } |
Hugh Dickins | 12d2710 | 2012-01-12 17:19:52 -0800 | [diff] [blame] | 843 | #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
Andrea Arcangeli | 71e3aac | 2011-01-13 15:46:52 -0800 | [diff] [blame] | 844 | |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 845 | static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec, |
| 846 | void *arg) |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 847 | { |
| 848 | enum lru_list lru = (enum lru_list)arg; |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 849 | int file = is_file_lru(lru); |
| 850 | int active = is_active_lru(lru); |
| 851 | |
| 852 | VM_BUG_ON(PageActive(page)); |
| 853 | VM_BUG_ON(PageUnevictable(page)); |
| 854 | VM_BUG_ON(PageLRU(page)); |
| 855 | |
| 856 | SetPageLRU(page); |
| 857 | if (active) |
| 858 | SetPageActive(page); |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 859 | add_page_to_lru_list(page, lruvec, lru); |
| 860 | update_page_reclaim_stat(lruvec, file, active); |
Shaohua Li | 3dd7ae8 | 2011-03-22 16:33:45 -0700 | [diff] [blame] | 861 | } |
| 862 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 863 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 864 | * Add the passed pages to the LRU, then drop the caller's refcount |
| 865 | * on them. Reinitialises the caller's pagevec. |
| 866 | */ |
Hugh Dickins | 5095ae83 | 2012-01-12 17:19:58 -0800 | [diff] [blame] | 867 | void __pagevec_lru_add(struct pagevec *pvec, enum lru_list lru) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 868 | { |
Lee Schermerhorn | 894bc31 | 2008-10-18 20:26:39 -0700 | [diff] [blame] | 869 | VM_BUG_ON(is_unevictable_lru(lru)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 870 | |
Hugh Dickins | 5095ae83 | 2012-01-12 17:19:58 -0800 | [diff] [blame] | 871 | pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, (void *)lru); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 872 | } |
Hugh Dickins | 5095ae83 | 2012-01-12 17:19:58 -0800 | [diff] [blame] | 873 | EXPORT_SYMBOL(__pagevec_lru_add); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 874 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 875 | /** |
| 876 | * pagevec_lookup - gang pagecache lookup |
| 877 | * @pvec: Where the resulting pages are placed |
| 878 | * @mapping: The address_space to search |
| 879 | * @start: The starting page index |
| 880 | * @nr_pages: The maximum number of pages |
| 881 | * |
| 882 | * pagevec_lookup() will search for and return a group of up to @nr_pages pages |
| 883 | * in the mapping. The pages are placed in @pvec. pagevec_lookup() takes a |
| 884 | * reference against the pages in @pvec. |
| 885 | * |
| 886 | * The search returns a group of mapping-contiguous pages with ascending |
| 887 | * indexes. There may be holes in the indices due to not-present pages. |
| 888 | * |
| 889 | * pagevec_lookup() returns the number of pages which were found. |
| 890 | */ |
| 891 | unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping, |
| 892 | pgoff_t start, unsigned nr_pages) |
| 893 | { |
| 894 | pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages); |
| 895 | return pagevec_count(pvec); |
| 896 | } |
Christoph Hellwig | 78539fd | 2006-01-11 20:47:41 +1100 | [diff] [blame] | 897 | EXPORT_SYMBOL(pagevec_lookup); |
| 898 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 899 | unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping, |
| 900 | pgoff_t *index, int tag, unsigned nr_pages) |
| 901 | { |
| 902 | pvec->nr = find_get_pages_tag(mapping, index, tag, |
| 903 | nr_pages, pvec->pages); |
| 904 | return pagevec_count(pvec); |
| 905 | } |
Steve French | 7f28570 | 2005-11-01 10:22:55 -0800 | [diff] [blame] | 906 | EXPORT_SYMBOL(pagevec_lookup_tag); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 907 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 908 | /* |
| 909 | * Perform any setup for the swap system |
| 910 | */ |
| 911 | void __init swap_setup(void) |
| 912 | { |
Jan Beulich | 4481374 | 2009-09-21 17:03:05 -0700 | [diff] [blame] | 913 | unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT); |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 914 | #ifdef CONFIG_SWAP |
Shaohua Li | 33806f0 | 2013-02-22 16:34:37 -0800 | [diff] [blame] | 915 | int i; |
| 916 | |
| 917 | bdi_init(swapper_spaces[0].backing_dev_info); |
| 918 | for (i = 0; i < MAX_SWAPFILES; i++) { |
| 919 | spin_lock_init(&swapper_spaces[i].tree_lock); |
| 920 | INIT_LIST_HEAD(&swapper_spaces[i].i_mmap_nonlinear); |
| 921 | } |
Peter Zijlstra | e0bf68d | 2007-10-16 23:25:46 -0700 | [diff] [blame] | 922 | #endif |
| 923 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 924 | /* Use a smaller cluster for small-memory machines */ |
| 925 | if (megs < 16) |
| 926 | page_cluster = 2; |
| 927 | else |
| 928 | page_cluster = 3; |
| 929 | /* |
| 930 | * Right now other parts of the system means that we |
| 931 | * _really_ don't want to cluster much more |
| 932 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 933 | } |