Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2 | /* |
| 3 | * linux/mm/compaction.c |
| 4 | * |
| 5 | * Memory compaction for the reduction of external fragmentation. Note that |
| 6 | * this heavily depends upon page migration to do all the real heavy |
| 7 | * lifting |
| 8 | * |
| 9 | * Copyright IBM Corp. 2007-2010 Mel Gorman <mel@csn.ul.ie> |
| 10 | */ |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 11 | #include <linux/cpu.h> |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 12 | #include <linux/swap.h> |
| 13 | #include <linux/migrate.h> |
| 14 | #include <linux/compaction.h> |
| 15 | #include <linux/mm_inline.h> |
Ingo Molnar | 174cd4b | 2017-02-02 19:15:33 +0100 | [diff] [blame] | 16 | #include <linux/sched/signal.h> |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 17 | #include <linux/backing-dev.h> |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 18 | #include <linux/sysctl.h> |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 19 | #include <linux/sysfs.h> |
Minchan Kim | 194159f | 2013-02-22 16:33:58 -0800 | [diff] [blame] | 20 | #include <linux/page-isolation.h> |
Andrey Ryabinin | b8c73fc | 2015-02-13 14:39:28 -0800 | [diff] [blame] | 21 | #include <linux/kasan.h> |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 22 | #include <linux/kthread.h> |
| 23 | #include <linux/freezer.h> |
Joonsoo Kim | 83358ec | 2016-07-26 15:23:43 -0700 | [diff] [blame] | 24 | #include <linux/page_owner.h> |
Johannes Weiner | eb41468 | 2018-10-26 15:06:27 -0700 | [diff] [blame] | 25 | #include <linux/psi.h> |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 26 | #include "internal.h" |
| 27 | |
Minchan Kim | 010fc29 | 2012-12-20 15:05:06 -0800 | [diff] [blame] | 28 | #ifdef CONFIG_COMPACTION |
| 29 | static inline void count_compact_event(enum vm_event_item item) |
| 30 | { |
| 31 | count_vm_event(item); |
| 32 | } |
| 33 | |
| 34 | static inline void count_compact_events(enum vm_event_item item, long delta) |
| 35 | { |
| 36 | count_vm_events(item, delta); |
| 37 | } |
| 38 | #else |
| 39 | #define count_compact_event(item) do { } while (0) |
| 40 | #define count_compact_events(item, delta) do { } while (0) |
| 41 | #endif |
| 42 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 43 | #if defined CONFIG_COMPACTION || defined CONFIG_CMA |
| 44 | |
Mel Gorman | b7aba69 | 2011-01-13 15:45:54 -0800 | [diff] [blame] | 45 | #define CREATE_TRACE_POINTS |
| 46 | #include <trace/events/compaction.h> |
| 47 | |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 48 | #define block_start_pfn(pfn, order) round_down(pfn, 1UL << (order)) |
| 49 | #define block_end_pfn(pfn, order) ALIGN((pfn) + 1, 1UL << (order)) |
| 50 | #define pageblock_start_pfn(pfn) block_start_pfn(pfn, pageblock_order) |
| 51 | #define pageblock_end_pfn(pfn) block_end_pfn(pfn, pageblock_order) |
| 52 | |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 53 | /* |
| 54 | * Fragmentation score check interval for proactive compaction purposes. |
| 55 | */ |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 56 | static const unsigned int HPAGE_FRAG_CHECK_INTERVAL_MSEC = 500; |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 57 | |
| 58 | /* |
| 59 | * Page order with-respect-to which proactive compaction |
| 60 | * calculates external fragmentation, which is used as |
| 61 | * the "fragmentation score" of a node/zone. |
| 62 | */ |
| 63 | #if defined CONFIG_TRANSPARENT_HUGEPAGE |
| 64 | #define COMPACTION_HPAGE_ORDER HPAGE_PMD_ORDER |
Nitin Gupta | 2578873 | 2020-08-11 18:31:04 -0700 | [diff] [blame] | 65 | #elif defined CONFIG_HUGETLBFS |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 66 | #define COMPACTION_HPAGE_ORDER HUGETLB_PAGE_ORDER |
| 67 | #else |
| 68 | #define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT) |
| 69 | #endif |
| 70 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 71 | static unsigned long release_freepages(struct list_head *freelist) |
| 72 | { |
| 73 | struct page *page, *next; |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 74 | unsigned long high_pfn = 0; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 75 | |
| 76 | list_for_each_entry_safe(page, next, freelist, lru) { |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 77 | unsigned long pfn = page_to_pfn(page); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 78 | list_del(&page->lru); |
| 79 | __free_page(page); |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 80 | if (pfn > high_pfn) |
| 81 | high_pfn = pfn; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 82 | } |
| 83 | |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 84 | return high_pfn; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 85 | } |
| 86 | |
Mel Gorman | 4469ab9 | 2019-03-05 15:44:39 -0800 | [diff] [blame] | 87 | static void split_map_pages(struct list_head *list) |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 88 | { |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 89 | unsigned int i, order, nr_pages; |
| 90 | struct page *page, *next; |
| 91 | LIST_HEAD(tmp_list); |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 92 | |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 93 | list_for_each_entry_safe(page, next, list, lru) { |
| 94 | list_del(&page->lru); |
| 95 | |
| 96 | order = page_private(page); |
| 97 | nr_pages = 1 << order; |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 98 | |
Joonsoo Kim | 46f24fd | 2016-07-26 15:23:58 -0700 | [diff] [blame] | 99 | post_alloc_hook(page, order, __GFP_MOVABLE); |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 100 | if (order) |
| 101 | split_page(page, order); |
| 102 | |
| 103 | for (i = 0; i < nr_pages; i++) { |
| 104 | list_add(&page->lru, &tmp_list); |
| 105 | page++; |
| 106 | } |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 107 | } |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 108 | |
| 109 | list_splice(&tmp_list, list); |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 110 | } |
| 111 | |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 112 | #ifdef CONFIG_COMPACTION |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 113 | |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 114 | int PageMovable(struct page *page) |
| 115 | { |
| 116 | struct address_space *mapping; |
| 117 | |
| 118 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
| 119 | if (!__PageMovable(page)) |
| 120 | return 0; |
| 121 | |
| 122 | mapping = page_mapping(page); |
| 123 | if (mapping && mapping->a_ops && mapping->a_ops->isolate_page) |
| 124 | return 1; |
| 125 | |
| 126 | return 0; |
| 127 | } |
| 128 | EXPORT_SYMBOL(PageMovable); |
| 129 | |
| 130 | void __SetPageMovable(struct page *page, struct address_space *mapping) |
| 131 | { |
| 132 | VM_BUG_ON_PAGE(!PageLocked(page), page); |
| 133 | VM_BUG_ON_PAGE((unsigned long)mapping & PAGE_MAPPING_MOVABLE, page); |
| 134 | page->mapping = (void *)((unsigned long)mapping | PAGE_MAPPING_MOVABLE); |
| 135 | } |
| 136 | EXPORT_SYMBOL(__SetPageMovable); |
| 137 | |
| 138 | void __ClearPageMovable(struct page *page) |
| 139 | { |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 140 | VM_BUG_ON_PAGE(!PageMovable(page), page); |
| 141 | /* |
| 142 | * Clear registered address_space val with keeping PAGE_MAPPING_MOVABLE |
| 143 | * flag so that VM can catch up released page by driver after isolation. |
| 144 | * With it, VM migration doesn't try to put it back. |
| 145 | */ |
| 146 | page->mapping = (void *)((unsigned long)page->mapping & |
| 147 | PAGE_MAPPING_MOVABLE); |
| 148 | } |
| 149 | EXPORT_SYMBOL(__ClearPageMovable); |
| 150 | |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 151 | /* Do not skip compaction more than 64 times */ |
| 152 | #define COMPACT_MAX_DEFER_SHIFT 6 |
| 153 | |
| 154 | /* |
| 155 | * Compaction is deferred when compaction fails to result in a page |
Alex Shi | 860b327 | 2020-08-11 18:31:10 -0700 | [diff] [blame] | 156 | * allocation success. 1 << compact_defer_shift, compactions are skipped up |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 157 | * to a limit of 1 << COMPACT_MAX_DEFER_SHIFT |
| 158 | */ |
Hui Su | 2271b01 | 2020-12-14 19:12:46 -0800 | [diff] [blame] | 159 | static void defer_compaction(struct zone *zone, int order) |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 160 | { |
| 161 | zone->compact_considered = 0; |
| 162 | zone->compact_defer_shift++; |
| 163 | |
| 164 | if (order < zone->compact_order_failed) |
| 165 | zone->compact_order_failed = order; |
| 166 | |
| 167 | if (zone->compact_defer_shift > COMPACT_MAX_DEFER_SHIFT) |
| 168 | zone->compact_defer_shift = COMPACT_MAX_DEFER_SHIFT; |
| 169 | |
| 170 | trace_mm_compaction_defer_compaction(zone, order); |
| 171 | } |
| 172 | |
| 173 | /* Returns true if compaction should be skipped this time */ |
Hui Su | 2271b01 | 2020-12-14 19:12:46 -0800 | [diff] [blame] | 174 | static bool compaction_deferred(struct zone *zone, int order) |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 175 | { |
| 176 | unsigned long defer_limit = 1UL << zone->compact_defer_shift; |
| 177 | |
| 178 | if (order < zone->compact_order_failed) |
| 179 | return false; |
| 180 | |
| 181 | /* Avoid possible overflow */ |
Mateusz Nosek | 62b35fe | 2020-10-13 16:56:58 -0700 | [diff] [blame] | 182 | if (++zone->compact_considered >= defer_limit) { |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 183 | zone->compact_considered = defer_limit; |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 184 | return false; |
Mateusz Nosek | 62b35fe | 2020-10-13 16:56:58 -0700 | [diff] [blame] | 185 | } |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 186 | |
| 187 | trace_mm_compaction_deferred(zone, order); |
| 188 | |
| 189 | return true; |
| 190 | } |
| 191 | |
| 192 | /* |
| 193 | * Update defer tracking counters after successful compaction of given order, |
| 194 | * which means an allocation either succeeded (alloc_success == true) or is |
| 195 | * expected to succeed. |
| 196 | */ |
| 197 | void compaction_defer_reset(struct zone *zone, int order, |
| 198 | bool alloc_success) |
| 199 | { |
| 200 | if (alloc_success) { |
| 201 | zone->compact_considered = 0; |
| 202 | zone->compact_defer_shift = 0; |
| 203 | } |
| 204 | if (order >= zone->compact_order_failed) |
| 205 | zone->compact_order_failed = order + 1; |
| 206 | |
| 207 | trace_mm_compaction_defer_reset(zone, order); |
| 208 | } |
| 209 | |
| 210 | /* Returns true if restarting compaction after many failures */ |
Hui Su | 2271b01 | 2020-12-14 19:12:46 -0800 | [diff] [blame] | 211 | static bool compaction_restarting(struct zone *zone, int order) |
Joonsoo Kim | 24e2716 | 2015-02-11 15:27:09 -0800 | [diff] [blame] | 212 | { |
| 213 | if (order < zone->compact_order_failed) |
| 214 | return false; |
| 215 | |
| 216 | return zone->compact_defer_shift == COMPACT_MAX_DEFER_SHIFT && |
| 217 | zone->compact_considered >= 1UL << zone->compact_defer_shift; |
| 218 | } |
| 219 | |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 220 | /* Returns true if the pageblock should be scanned for pages to isolate. */ |
| 221 | static inline bool isolation_suitable(struct compact_control *cc, |
| 222 | struct page *page) |
| 223 | { |
| 224 | if (cc->ignore_skip_hint) |
| 225 | return true; |
| 226 | |
| 227 | return !get_pageblock_skip(page); |
| 228 | } |
| 229 | |
Vlastimil Babka | 02333641 | 2015-09-08 15:02:42 -0700 | [diff] [blame] | 230 | static void reset_cached_positions(struct zone *zone) |
| 231 | { |
| 232 | zone->compact_cached_migrate_pfn[0] = zone->zone_start_pfn; |
| 233 | zone->compact_cached_migrate_pfn[1] = zone->zone_start_pfn; |
Joonsoo Kim | 623446e | 2016-03-15 14:57:45 -0700 | [diff] [blame] | 234 | zone->compact_cached_free_pfn = |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 235 | pageblock_start_pfn(zone_end_pfn(zone) - 1); |
Vlastimil Babka | 02333641 | 2015-09-08 15:02:42 -0700 | [diff] [blame] | 236 | } |
| 237 | |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 238 | /* |
Hui Su | 2271b01 | 2020-12-14 19:12:46 -0800 | [diff] [blame] | 239 | * Compound pages of >= pageblock_order should consistently be skipped until |
Vlastimil Babka | b527cfe | 2017-11-17 15:26:34 -0800 | [diff] [blame] | 240 | * released. It is always pointless to compact pages of such order (if they are |
| 241 | * migratable), and the pageblocks they occupy cannot contain any free pages. |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 242 | */ |
Vlastimil Babka | b527cfe | 2017-11-17 15:26:34 -0800 | [diff] [blame] | 243 | static bool pageblock_skip_persistent(struct page *page) |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 244 | { |
Vlastimil Babka | b527cfe | 2017-11-17 15:26:34 -0800 | [diff] [blame] | 245 | if (!PageCompound(page)) |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 246 | return false; |
Vlastimil Babka | b527cfe | 2017-11-17 15:26:34 -0800 | [diff] [blame] | 247 | |
| 248 | page = compound_head(page); |
| 249 | |
| 250 | if (compound_order(page) >= pageblock_order) |
| 251 | return true; |
| 252 | |
| 253 | return false; |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 254 | } |
| 255 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 256 | static bool |
| 257 | __reset_isolation_pfn(struct zone *zone, unsigned long pfn, bool check_source, |
| 258 | bool check_target) |
| 259 | { |
| 260 | struct page *page = pfn_to_online_page(pfn); |
Mel Gorman | 6b0868c | 2019-04-04 11:54:09 +0100 | [diff] [blame] | 261 | struct page *block_page; |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 262 | struct page *end_page; |
| 263 | unsigned long block_pfn; |
| 264 | |
| 265 | if (!page) |
| 266 | return false; |
| 267 | if (zone != page_zone(page)) |
| 268 | return false; |
| 269 | if (pageblock_skip_persistent(page)) |
| 270 | return false; |
| 271 | |
| 272 | /* |
| 273 | * If skip is already cleared do no further checking once the |
| 274 | * restart points have been set. |
| 275 | */ |
| 276 | if (check_source && check_target && !get_pageblock_skip(page)) |
| 277 | return true; |
| 278 | |
| 279 | /* |
| 280 | * If clearing skip for the target scanner, do not select a |
| 281 | * non-movable pageblock as the starting point. |
| 282 | */ |
| 283 | if (!check_source && check_target && |
| 284 | get_pageblock_migratetype(page) != MIGRATE_MOVABLE) |
| 285 | return false; |
| 286 | |
Mel Gorman | 6b0868c | 2019-04-04 11:54:09 +0100 | [diff] [blame] | 287 | /* Ensure the start of the pageblock or zone is online and valid */ |
| 288 | block_pfn = pageblock_start_pfn(pfn); |
Vlastimil Babka | a2e9a5a | 2019-10-14 14:12:07 -0700 | [diff] [blame] | 289 | block_pfn = max(block_pfn, zone->zone_start_pfn); |
| 290 | block_page = pfn_to_online_page(block_pfn); |
Mel Gorman | 6b0868c | 2019-04-04 11:54:09 +0100 | [diff] [blame] | 291 | if (block_page) { |
| 292 | page = block_page; |
| 293 | pfn = block_pfn; |
| 294 | } |
| 295 | |
| 296 | /* Ensure the end of the pageblock or zone is online and valid */ |
Vlastimil Babka | a2e9a5a | 2019-10-14 14:12:07 -0700 | [diff] [blame] | 297 | block_pfn = pageblock_end_pfn(pfn) - 1; |
Mel Gorman | 6b0868c | 2019-04-04 11:54:09 +0100 | [diff] [blame] | 298 | block_pfn = min(block_pfn, zone_end_pfn(zone) - 1); |
| 299 | end_page = pfn_to_online_page(block_pfn); |
| 300 | if (!end_page) |
| 301 | return false; |
| 302 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 303 | /* |
| 304 | * Only clear the hint if a sample indicates there is either a |
| 305 | * free page or an LRU page in the block. One or other condition |
| 306 | * is necessary for the block to be a migration source/target. |
| 307 | */ |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 308 | do { |
| 309 | if (pfn_valid_within(pfn)) { |
| 310 | if (check_source && PageLRU(page)) { |
| 311 | clear_pageblock_skip(page); |
| 312 | return true; |
| 313 | } |
| 314 | |
| 315 | if (check_target && PageBuddy(page)) { |
| 316 | clear_pageblock_skip(page); |
| 317 | return true; |
| 318 | } |
| 319 | } |
| 320 | |
| 321 | page += (1 << PAGE_ALLOC_COSTLY_ORDER); |
| 322 | pfn += (1 << PAGE_ALLOC_COSTLY_ORDER); |
Vlastimil Babka | a2e9a5a | 2019-10-14 14:12:07 -0700 | [diff] [blame] | 323 | } while (page <= end_page); |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 324 | |
| 325 | return false; |
| 326 | } |
| 327 | |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 328 | /* |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 329 | * This function is called to clear all cached information on pageblocks that |
| 330 | * should be skipped for page isolation when the migrate and free page scanner |
| 331 | * meet. |
| 332 | */ |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 333 | static void __reset_isolation_suitable(struct zone *zone) |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 334 | { |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 335 | unsigned long migrate_pfn = zone->zone_start_pfn; |
Mel Gorman | 6b0868c | 2019-04-04 11:54:09 +0100 | [diff] [blame] | 336 | unsigned long free_pfn = zone_end_pfn(zone) - 1; |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 337 | unsigned long reset_migrate = free_pfn; |
| 338 | unsigned long reset_free = migrate_pfn; |
| 339 | bool source_set = false; |
| 340 | bool free_set = false; |
| 341 | |
| 342 | if (!zone->compact_blockskip_flush) |
| 343 | return; |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 344 | |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 345 | zone->compact_blockskip_flush = false; |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 346 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 347 | /* |
| 348 | * Walk the zone and update pageblock skip information. Source looks |
| 349 | * for PageLRU while target looks for PageBuddy. When the scanner |
| 350 | * is found, both PageBuddy and PageLRU are checked as the pageblock |
| 351 | * is suitable as both source and target. |
| 352 | */ |
| 353 | for (; migrate_pfn < free_pfn; migrate_pfn += pageblock_nr_pages, |
| 354 | free_pfn -= pageblock_nr_pages) { |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 355 | cond_resched(); |
| 356 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 357 | /* Update the migrate PFN */ |
| 358 | if (__reset_isolation_pfn(zone, migrate_pfn, true, source_set) && |
| 359 | migrate_pfn < reset_migrate) { |
| 360 | source_set = true; |
| 361 | reset_migrate = migrate_pfn; |
| 362 | zone->compact_init_migrate_pfn = reset_migrate; |
| 363 | zone->compact_cached_migrate_pfn[0] = reset_migrate; |
| 364 | zone->compact_cached_migrate_pfn[1] = reset_migrate; |
| 365 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 366 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 367 | /* Update the free PFN */ |
| 368 | if (__reset_isolation_pfn(zone, free_pfn, free_set, true) && |
| 369 | free_pfn > reset_free) { |
| 370 | free_set = true; |
| 371 | reset_free = free_pfn; |
| 372 | zone->compact_init_free_pfn = reset_free; |
| 373 | zone->compact_cached_free_pfn = reset_free; |
| 374 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 375 | } |
Vlastimil Babka | 02333641 | 2015-09-08 15:02:42 -0700 | [diff] [blame] | 376 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 377 | /* Leave no distance if no suitable block was reset */ |
| 378 | if (reset_migrate >= reset_free) { |
| 379 | zone->compact_cached_migrate_pfn[0] = migrate_pfn; |
| 380 | zone->compact_cached_migrate_pfn[1] = migrate_pfn; |
| 381 | zone->compact_cached_free_pfn = free_pfn; |
| 382 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 383 | } |
| 384 | |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 385 | void reset_isolation_suitable(pg_data_t *pgdat) |
| 386 | { |
| 387 | int zoneid; |
| 388 | |
| 389 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { |
| 390 | struct zone *zone = &pgdat->node_zones[zoneid]; |
| 391 | if (!populated_zone(zone)) |
| 392 | continue; |
| 393 | |
| 394 | /* Only flush if a full compaction finished recently */ |
| 395 | if (zone->compact_blockskip_flush) |
| 396 | __reset_isolation_suitable(zone); |
| 397 | } |
| 398 | } |
| 399 | |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 400 | /* |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 401 | * Sets the pageblock skip bit if it was clear. Note that this is a hint as |
| 402 | * locks are not required for read/writers. Returns true if it was already set. |
| 403 | */ |
| 404 | static bool test_and_set_skip(struct compact_control *cc, struct page *page, |
| 405 | unsigned long pfn) |
| 406 | { |
| 407 | bool skip; |
| 408 | |
| 409 | /* Do no update if skip hint is being ignored */ |
| 410 | if (cc->ignore_skip_hint) |
| 411 | return false; |
| 412 | |
| 413 | if (!IS_ALIGNED(pfn, pageblock_nr_pages)) |
| 414 | return false; |
| 415 | |
| 416 | skip = get_pageblock_skip(page); |
| 417 | if (!skip && !cc->no_set_skip_hint) |
| 418 | set_pageblock_skip(page); |
| 419 | |
| 420 | return skip; |
| 421 | } |
| 422 | |
| 423 | static void update_cached_migrate(struct compact_control *cc, unsigned long pfn) |
| 424 | { |
| 425 | struct zone *zone = cc->zone; |
| 426 | |
| 427 | pfn = pageblock_end_pfn(pfn); |
| 428 | |
| 429 | /* Set for isolation rather than compaction */ |
| 430 | if (cc->no_set_skip_hint) |
| 431 | return; |
| 432 | |
| 433 | if (pfn > zone->compact_cached_migrate_pfn[0]) |
| 434 | zone->compact_cached_migrate_pfn[0] = pfn; |
| 435 | if (cc->mode != MIGRATE_ASYNC && |
| 436 | pfn > zone->compact_cached_migrate_pfn[1]) |
| 437 | zone->compact_cached_migrate_pfn[1] = pfn; |
| 438 | } |
| 439 | |
| 440 | /* |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 441 | * If no pages were isolated then mark this pageblock to be skipped in the |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 442 | * future. The information is later cleared by __reset_isolation_suitable(). |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 443 | */ |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 444 | static void update_pageblock_skip(struct compact_control *cc, |
Mel Gorman | d097a6f | 2019-03-05 15:45:28 -0800 | [diff] [blame] | 445 | struct page *page, unsigned long pfn) |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 446 | { |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 447 | struct zone *zone = cc->zone; |
Joonsoo Kim | 6815bf3 | 2013-12-18 17:08:52 -0800 | [diff] [blame] | 448 | |
Vlastimil Babka | 2583d67 | 2017-11-17 15:26:38 -0800 | [diff] [blame] | 449 | if (cc->no_set_skip_hint) |
Joonsoo Kim | 6815bf3 | 2013-12-18 17:08:52 -0800 | [diff] [blame] | 450 | return; |
| 451 | |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 452 | if (!page) |
| 453 | return; |
| 454 | |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 455 | set_pageblock_skip(page); |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 456 | |
David Rientjes | 35979ef | 2014-06-04 16:08:27 -0700 | [diff] [blame] | 457 | /* Update where async and sync compaction should restart */ |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 458 | if (pfn < zone->compact_cached_free_pfn) |
| 459 | zone->compact_cached_free_pfn = pfn; |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 460 | } |
| 461 | #else |
| 462 | static inline bool isolation_suitable(struct compact_control *cc, |
| 463 | struct page *page) |
| 464 | { |
| 465 | return true; |
| 466 | } |
| 467 | |
Vlastimil Babka | b527cfe | 2017-11-17 15:26:34 -0800 | [diff] [blame] | 468 | static inline bool pageblock_skip_persistent(struct page *page) |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 469 | { |
| 470 | return false; |
| 471 | } |
| 472 | |
| 473 | static inline void update_pageblock_skip(struct compact_control *cc, |
Mel Gorman | d097a6f | 2019-03-05 15:45:28 -0800 | [diff] [blame] | 474 | struct page *page, unsigned long pfn) |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 475 | { |
| 476 | } |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 477 | |
| 478 | static void update_cached_migrate(struct compact_control *cc, unsigned long pfn) |
| 479 | { |
| 480 | } |
| 481 | |
| 482 | static bool test_and_set_skip(struct compact_control *cc, struct page *page, |
| 483 | unsigned long pfn) |
| 484 | { |
| 485 | return false; |
| 486 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 487 | #endif /* CONFIG_COMPACTION */ |
| 488 | |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 489 | /* |
| 490 | * Compaction requires the taking of some coarse locks that are potentially |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 491 | * very heavily contended. For async compaction, trylock and record if the |
| 492 | * lock is contended. The lock will still be acquired but compaction will |
| 493 | * abort when the current block is finished regardless of success rate. |
| 494 | * Sync compaction acquires the lock. |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 495 | * |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 496 | * Always returns true which makes it easier to track lock state in callers. |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 497 | */ |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 498 | static bool compact_lock_irqsave(spinlock_t *lock, unsigned long *flags, |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 499 | struct compact_control *cc) |
Jules Irenge | 77337ed | 2020-04-06 20:08:06 -0700 | [diff] [blame] | 500 | __acquires(lock) |
Mel Gorman | 2a1402aa | 2012-10-08 16:32:33 -0700 | [diff] [blame] | 501 | { |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 502 | /* Track if the lock is contended in async mode */ |
| 503 | if (cc->mode == MIGRATE_ASYNC && !cc->contended) { |
| 504 | if (spin_trylock_irqsave(lock, *flags)) |
| 505 | return true; |
| 506 | |
| 507 | cc->contended = true; |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 508 | } |
Vlastimil Babka | 1f9efde | 2014-10-09 15:27:14 -0700 | [diff] [blame] | 509 | |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 510 | spin_lock_irqsave(lock, *flags); |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 511 | return true; |
Mel Gorman | 2a1402aa | 2012-10-08 16:32:33 -0700 | [diff] [blame] | 512 | } |
| 513 | |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 514 | /* |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 515 | * Compaction requires the taking of some coarse locks that are potentially |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 516 | * very heavily contended. The lock should be periodically unlocked to avoid |
| 517 | * having disabled IRQs for a long time, even when there is nobody waiting on |
| 518 | * the lock. It might also be that allowing the IRQs will result in |
| 519 | * need_resched() becoming true. If scheduling is needed, async compaction |
| 520 | * aborts. Sync compaction schedules. |
| 521 | * Either compaction type will also abort if a fatal signal is pending. |
| 522 | * In either case if the lock was locked, it is dropped and not regained. |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 523 | * |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 524 | * Returns true if compaction should abort due to fatal signal pending, or |
| 525 | * async compaction due to need_resched() |
| 526 | * Returns false when compaction can continue (sync compaction might have |
| 527 | * scheduled) |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 528 | */ |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 529 | static bool compact_unlock_should_abort(spinlock_t *lock, |
| 530 | unsigned long flags, bool *locked, struct compact_control *cc) |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 531 | { |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 532 | if (*locked) { |
| 533 | spin_unlock_irqrestore(lock, flags); |
| 534 | *locked = false; |
| 535 | } |
Vlastimil Babka | 1f9efde | 2014-10-09 15:27:14 -0700 | [diff] [blame] | 536 | |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 537 | if (fatal_signal_pending(current)) { |
Vlastimil Babka | c3486f5 | 2016-07-28 15:49:30 -0700 | [diff] [blame] | 538 | cc->contended = true; |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 539 | return true; |
| 540 | } |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 541 | |
Mel Gorman | cf66f07 | 2019-03-05 15:45:24 -0800 | [diff] [blame] | 542 | cond_resched(); |
Vlastimil Babka | be97657 | 2014-06-04 16:10:41 -0700 | [diff] [blame] | 543 | |
| 544 | return false; |
| 545 | } |
| 546 | |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 547 | /* |
Jerome Marchand | 9e4be47 | 2013-11-12 15:07:12 -0800 | [diff] [blame] | 548 | * Isolate free pages onto a private freelist. If @strict is true, will abort |
| 549 | * returning 0 on any invalid PFNs or non-free pages inside of the pageblock |
| 550 | * (even though it may still end up isolating some pages). |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 551 | */ |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 552 | static unsigned long isolate_freepages_block(struct compact_control *cc, |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 553 | unsigned long *start_pfn, |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 554 | unsigned long end_pfn, |
| 555 | struct list_head *freelist, |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 556 | unsigned int stride, |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 557 | bool strict) |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 558 | { |
Mel Gorman | b7aba69 | 2011-01-13 15:45:54 -0800 | [diff] [blame] | 559 | int nr_scanned = 0, total_isolated = 0; |
Mel Gorman | d097a6f | 2019-03-05 15:45:28 -0800 | [diff] [blame] | 560 | struct page *cursor; |
Xiubo Li | b8b2d82 | 2014-10-09 15:28:21 -0700 | [diff] [blame] | 561 | unsigned long flags = 0; |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 562 | bool locked = false; |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 563 | unsigned long blockpfn = *start_pfn; |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 564 | unsigned int order; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 565 | |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 566 | /* Strict mode is for isolation, speed is secondary */ |
| 567 | if (strict) |
| 568 | stride = 1; |
| 569 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 570 | cursor = pfn_to_page(blockpfn); |
| 571 | |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 572 | /* Isolate free pages. */ |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 573 | for (; blockpfn < end_pfn; blockpfn += stride, cursor += stride) { |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 574 | int isolated; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 575 | struct page *page = cursor; |
| 576 | |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 577 | /* |
| 578 | * Periodically drop the lock (if held) regardless of its |
| 579 | * contention, to give chance to IRQs. Abort if fatal signal |
| 580 | * pending or async compaction detects need_resched() |
| 581 | */ |
| 582 | if (!(blockpfn % SWAP_CLUSTER_MAX) |
| 583 | && compact_unlock_should_abort(&cc->zone->lock, flags, |
| 584 | &locked, cc)) |
| 585 | break; |
| 586 | |
Mel Gorman | b7aba69 | 2011-01-13 15:45:54 -0800 | [diff] [blame] | 587 | nr_scanned++; |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 588 | if (!pfn_valid_within(blockpfn)) |
Laura Abbott | 2af120b | 2014-03-10 15:49:44 -0700 | [diff] [blame] | 589 | goto isolate_fail; |
| 590 | |
Vlastimil Babka | 9fcd6d2 | 2015-09-08 15:02:49 -0700 | [diff] [blame] | 591 | /* |
| 592 | * For compound pages such as THP and hugetlbfs, we can save |
| 593 | * potentially a lot of iterations if we skip them at once. |
| 594 | * The check is racy, but we can consider only valid values |
| 595 | * and the only danger is skipping too much. |
| 596 | */ |
| 597 | if (PageCompound(page)) { |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 598 | const unsigned int order = compound_order(page); |
Vlastimil Babka | 9fcd6d2 | 2015-09-08 15:02:49 -0700 | [diff] [blame] | 599 | |
Vlastimil Babka | d3c85ba | 2017-11-17 15:26:41 -0800 | [diff] [blame] | 600 | if (likely(order < MAX_ORDER)) { |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 601 | blockpfn += (1UL << order) - 1; |
| 602 | cursor += (1UL << order) - 1; |
Vlastimil Babka | 9fcd6d2 | 2015-09-08 15:02:49 -0700 | [diff] [blame] | 603 | } |
Vlastimil Babka | 9fcd6d2 | 2015-09-08 15:02:49 -0700 | [diff] [blame] | 604 | goto isolate_fail; |
| 605 | } |
| 606 | |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 607 | if (!PageBuddy(page)) |
Laura Abbott | 2af120b | 2014-03-10 15:49:44 -0700 | [diff] [blame] | 608 | goto isolate_fail; |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 609 | |
| 610 | /* |
Vlastimil Babka | 69b7189 | 2014-10-09 15:27:18 -0700 | [diff] [blame] | 611 | * If we already hold the lock, we can skip some rechecking. |
| 612 | * Note that if we hold the lock now, checked_pageblock was |
| 613 | * already set in some previous iteration (or strict is true), |
| 614 | * so it is correct to skip the suitable migration target |
| 615 | * recheck as well. |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 616 | */ |
Vlastimil Babka | 69b7189 | 2014-10-09 15:27:18 -0700 | [diff] [blame] | 617 | if (!locked) { |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 618 | locked = compact_lock_irqsave(&cc->zone->lock, |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 619 | &flags, cc); |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 620 | |
Vlastimil Babka | 69b7189 | 2014-10-09 15:27:18 -0700 | [diff] [blame] | 621 | /* Recheck this is a buddy page under lock */ |
| 622 | if (!PageBuddy(page)) |
| 623 | goto isolate_fail; |
| 624 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 625 | |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 626 | /* Found a free page, will break it into order-0 pages */ |
Matthew Wilcox (Oracle) | ab130f91 | 2020-10-15 20:10:15 -0700 | [diff] [blame] | 627 | order = buddy_order(page); |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 628 | isolated = __isolate_free_page(page, order); |
David Rientjes | a4f04f2 | 2016-06-24 14:50:10 -0700 | [diff] [blame] | 629 | if (!isolated) |
| 630 | break; |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 631 | set_page_private(page, order); |
David Rientjes | a4f04f2 | 2016-06-24 14:50:10 -0700 | [diff] [blame] | 632 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 633 | total_isolated += isolated; |
David Rientjes | a4f04f2 | 2016-06-24 14:50:10 -0700 | [diff] [blame] | 634 | cc->nr_freepages += isolated; |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 635 | list_add_tail(&page->lru, freelist); |
| 636 | |
David Rientjes | a4f04f2 | 2016-06-24 14:50:10 -0700 | [diff] [blame] | 637 | if (!strict && cc->nr_migratepages <= cc->nr_freepages) { |
| 638 | blockpfn += isolated; |
| 639 | break; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 640 | } |
David Rientjes | a4f04f2 | 2016-06-24 14:50:10 -0700 | [diff] [blame] | 641 | /* Advance to the end of split page */ |
| 642 | blockpfn += isolated - 1; |
| 643 | cursor += isolated - 1; |
| 644 | continue; |
Laura Abbott | 2af120b | 2014-03-10 15:49:44 -0700 | [diff] [blame] | 645 | |
| 646 | isolate_fail: |
| 647 | if (strict) |
| 648 | break; |
| 649 | else |
| 650 | continue; |
| 651 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 652 | } |
| 653 | |
David Rientjes | a4f04f2 | 2016-06-24 14:50:10 -0700 | [diff] [blame] | 654 | if (locked) |
| 655 | spin_unlock_irqrestore(&cc->zone->lock, flags); |
| 656 | |
Vlastimil Babka | 9fcd6d2 | 2015-09-08 15:02:49 -0700 | [diff] [blame] | 657 | /* |
| 658 | * There is a tiny chance that we have read bogus compound_order(), |
| 659 | * so be careful to not go outside of the pageblock. |
| 660 | */ |
| 661 | if (unlikely(blockpfn > end_pfn)) |
| 662 | blockpfn = end_pfn; |
| 663 | |
Joonsoo Kim | e34d85f | 2015-02-11 15:27:04 -0800 | [diff] [blame] | 664 | trace_mm_compaction_isolate_freepages(*start_pfn, blockpfn, |
| 665 | nr_scanned, total_isolated); |
| 666 | |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 667 | /* Record how far we have got within the block */ |
| 668 | *start_pfn = blockpfn; |
| 669 | |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 670 | /* |
| 671 | * If strict isolation is requested by CMA then check that all the |
| 672 | * pages requested were isolated. If there were any failures, 0 is |
| 673 | * returned and CMA will fail. |
| 674 | */ |
Laura Abbott | 2af120b | 2014-03-10 15:49:44 -0700 | [diff] [blame] | 675 | if (strict && blockpfn < end_pfn) |
Mel Gorman | f40d1e4 | 2012-10-08 16:32:36 -0700 | [diff] [blame] | 676 | total_isolated = 0; |
| 677 | |
David Rientjes | 7f354a5 | 2017-02-22 15:44:50 -0800 | [diff] [blame] | 678 | cc->total_free_scanned += nr_scanned; |
Mel Gorman | 397487d | 2012-10-19 12:00:10 +0100 | [diff] [blame] | 679 | if (total_isolated) |
Minchan Kim | 010fc29 | 2012-12-20 15:05:06 -0800 | [diff] [blame] | 680 | count_compact_events(COMPACTISOLATED, total_isolated); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 681 | return total_isolated; |
| 682 | } |
| 683 | |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 684 | /** |
| 685 | * isolate_freepages_range() - isolate free pages. |
Mike Rapoport | e8b098f | 2018-04-05 16:24:57 -0700 | [diff] [blame] | 686 | * @cc: Compaction control structure. |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 687 | * @start_pfn: The first PFN to start isolating. |
| 688 | * @end_pfn: The one-past-last PFN. |
| 689 | * |
| 690 | * Non-free pages, invalid PFNs, or zone boundaries within the |
| 691 | * [start_pfn, end_pfn) range are considered errors, cause function to |
| 692 | * undo its actions and return zero. |
| 693 | * |
| 694 | * Otherwise, function returns one-past-the-last PFN of isolated page |
| 695 | * (which may be greater then end_pfn if end fell in a middle of |
| 696 | * a free page). |
| 697 | */ |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 698 | unsigned long |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 699 | isolate_freepages_range(struct compact_control *cc, |
| 700 | unsigned long start_pfn, unsigned long end_pfn) |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 701 | { |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 702 | unsigned long isolated, pfn, block_start_pfn, block_end_pfn; |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 703 | LIST_HEAD(freelist); |
| 704 | |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 705 | pfn = start_pfn; |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 706 | block_start_pfn = pageblock_start_pfn(pfn); |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 707 | if (block_start_pfn < cc->zone->zone_start_pfn) |
| 708 | block_start_pfn = cc->zone->zone_start_pfn; |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 709 | block_end_pfn = pageblock_end_pfn(pfn); |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 710 | |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 711 | for (; pfn < end_pfn; pfn += isolated, |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 712 | block_start_pfn = block_end_pfn, |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 713 | block_end_pfn += pageblock_nr_pages) { |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 714 | /* Protect pfn from changing by isolate_freepages_block */ |
| 715 | unsigned long isolate_start_pfn = pfn; |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 716 | |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 717 | block_end_pfn = min(block_end_pfn, end_pfn); |
| 718 | |
Joonsoo Kim | 5842001 | 2014-11-13 15:19:07 -0800 | [diff] [blame] | 719 | /* |
| 720 | * pfn could pass the block_end_pfn if isolated freepage |
| 721 | * is more than pageblock order. In this case, we adjust |
| 722 | * scanning range to right one. |
| 723 | */ |
| 724 | if (pfn >= block_end_pfn) { |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 725 | block_start_pfn = pageblock_start_pfn(pfn); |
| 726 | block_end_pfn = pageblock_end_pfn(pfn); |
Joonsoo Kim | 5842001 | 2014-11-13 15:19:07 -0800 | [diff] [blame] | 727 | block_end_pfn = min(block_end_pfn, end_pfn); |
| 728 | } |
| 729 | |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 730 | if (!pageblock_pfn_to_page(block_start_pfn, |
| 731 | block_end_pfn, cc->zone)) |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 732 | break; |
| 733 | |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 734 | isolated = isolate_freepages_block(cc, &isolate_start_pfn, |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 735 | block_end_pfn, &freelist, 0, true); |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 736 | |
| 737 | /* |
| 738 | * In strict mode, isolate_freepages_block() returns 0 if |
| 739 | * there are any holes in the block (ie. invalid PFNs or |
| 740 | * non-free pages). |
| 741 | */ |
| 742 | if (!isolated) |
| 743 | break; |
| 744 | |
| 745 | /* |
| 746 | * If we managed to isolate pages, it is always (1 << n) * |
| 747 | * pageblock_nr_pages for some non-negative n. (Max order |
| 748 | * page may span two pageblocks). |
| 749 | */ |
| 750 | } |
| 751 | |
Joonsoo Kim | 66c6422 | 2016-07-26 15:23:40 -0700 | [diff] [blame] | 752 | /* __isolate_free_page() does not map the pages */ |
Mel Gorman | 4469ab9 | 2019-03-05 15:44:39 -0800 | [diff] [blame] | 753 | split_map_pages(&freelist); |
Michal Nazarewicz | 85aa125 | 2012-01-30 13:24:03 +0100 | [diff] [blame] | 754 | |
| 755 | if (pfn < end_pfn) { |
| 756 | /* Loop terminated early, cleanup. */ |
| 757 | release_freepages(&freelist); |
| 758 | return 0; |
| 759 | } |
| 760 | |
| 761 | /* We don't use freelists for anything. */ |
| 762 | return pfn; |
| 763 | } |
| 764 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 765 | /* Similar to reclaim, but different enough that they don't share logic */ |
Andrey Ryabinin | 5f438ee | 2019-03-05 15:49:42 -0800 | [diff] [blame] | 766 | static bool too_many_isolated(pg_data_t *pgdat) |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 767 | { |
Minchan Kim | bc69304 | 2010-09-09 16:38:00 -0700 | [diff] [blame] | 768 | unsigned long active, inactive, isolated; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 769 | |
Andrey Ryabinin | 5f438ee | 2019-03-05 15:49:42 -0800 | [diff] [blame] | 770 | inactive = node_page_state(pgdat, NR_INACTIVE_FILE) + |
| 771 | node_page_state(pgdat, NR_INACTIVE_ANON); |
| 772 | active = node_page_state(pgdat, NR_ACTIVE_FILE) + |
| 773 | node_page_state(pgdat, NR_ACTIVE_ANON); |
| 774 | isolated = node_page_state(pgdat, NR_ISOLATED_FILE) + |
| 775 | node_page_state(pgdat, NR_ISOLATED_ANON); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 776 | |
Minchan Kim | bc69304 | 2010-09-09 16:38:00 -0700 | [diff] [blame] | 777 | return isolated > (inactive + active) / 2; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 778 | } |
| 779 | |
Michal Nazarewicz | 2fe86e0 | 2012-01-30 13:16:26 +0100 | [diff] [blame] | 780 | /** |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 781 | * isolate_migratepages_block() - isolate all migrate-able pages within |
| 782 | * a single pageblock |
Michal Nazarewicz | 2fe86e0 | 2012-01-30 13:16:26 +0100 | [diff] [blame] | 783 | * @cc: Compaction control structure. |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 784 | * @low_pfn: The first PFN to isolate |
| 785 | * @end_pfn: The one-past-the-last PFN to isolate, within same pageblock |
| 786 | * @isolate_mode: Isolation mode to be used. |
Michal Nazarewicz | 2fe86e0 | 2012-01-30 13:16:26 +0100 | [diff] [blame] | 787 | * |
| 788 | * Isolate all pages that can be migrated from the range specified by |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 789 | * [low_pfn, end_pfn). The range is expected to be within same pageblock. |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 790 | * Returns errno, like -EAGAIN or -EINTR in case e.g signal pending or congestion, |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 791 | * -ENOMEM in case we could not allocate a page, or 0. |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 792 | * cc->migrate_pfn will contain the next pfn to scan. |
Michal Nazarewicz | 2fe86e0 | 2012-01-30 13:16:26 +0100 | [diff] [blame] | 793 | * |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 794 | * The pages are isolated on cc->migratepages list (not required to be empty), |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 795 | * and cc->nr_migratepages is updated accordingly. |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 796 | */ |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 797 | static int |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 798 | isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, |
| 799 | unsigned long end_pfn, isolate_mode_t isolate_mode) |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 800 | { |
Andrey Ryabinin | 5f438ee | 2019-03-05 15:49:42 -0800 | [diff] [blame] | 801 | pg_data_t *pgdat = cc->zone->zone_pgdat; |
Mel Gorman | b7aba69 | 2011-01-13 15:45:54 -0800 | [diff] [blame] | 802 | unsigned long nr_scanned = 0, nr_isolated = 0; |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 803 | struct lruvec *lruvec; |
Xiubo Li | b8b2d82 | 2014-10-09 15:28:21 -0700 | [diff] [blame] | 804 | unsigned long flags = 0; |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 805 | struct lruvec *locked = NULL; |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 806 | struct page *page = NULL, *valid_page = NULL; |
Joonsoo Kim | e34d85f | 2015-02-11 15:27:04 -0800 | [diff] [blame] | 807 | unsigned long start_pfn = low_pfn; |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 808 | bool skip_on_failure = false; |
| 809 | unsigned long next_skip_pfn = 0; |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 810 | bool skip_updated = false; |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 811 | int ret = 0; |
| 812 | |
| 813 | cc->migrate_pfn = low_pfn; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 814 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 815 | /* |
| 816 | * Ensure that there are not too many pages isolated from the LRU |
| 817 | * list by either parallel reclaimers or compaction. If there are, |
| 818 | * delay for some time until fewer pages are isolated |
| 819 | */ |
Andrey Ryabinin | 5f438ee | 2019-03-05 15:49:42 -0800 | [diff] [blame] | 820 | while (unlikely(too_many_isolated(pgdat))) { |
Zi Yan | d20bdd57 | 2020-11-13 22:51:43 -0800 | [diff] [blame] | 821 | /* stop isolation if there are still pages not migrated */ |
| 822 | if (cc->nr_migratepages) |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 823 | return -EAGAIN; |
Zi Yan | d20bdd57 | 2020-11-13 22:51:43 -0800 | [diff] [blame] | 824 | |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 825 | /* async migration should just abort */ |
David Rientjes | e0b9dae | 2014-06-04 16:08:28 -0700 | [diff] [blame] | 826 | if (cc->mode == MIGRATE_ASYNC) |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 827 | return -EAGAIN; |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 828 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 829 | congestion_wait(BLK_RW_ASYNC, HZ/10); |
| 830 | |
| 831 | if (fatal_signal_pending(current)) |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 832 | return -EINTR; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 833 | } |
| 834 | |
Mel Gorman | cf66f07 | 2019-03-05 15:45:24 -0800 | [diff] [blame] | 835 | cond_resched(); |
David Rientjes | aeef4b8 | 2014-06-04 16:08:31 -0700 | [diff] [blame] | 836 | |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 837 | if (cc->direct_compaction && (cc->mode == MIGRATE_ASYNC)) { |
| 838 | skip_on_failure = true; |
| 839 | next_skip_pfn = block_end_pfn(low_pfn, cc->order); |
| 840 | } |
| 841 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 842 | /* Time to isolate some pages for migration */ |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 843 | for (; low_pfn < end_pfn; low_pfn++) { |
Vlastimil Babka | 29c0dde | 2015-09-08 15:02:46 -0700 | [diff] [blame] | 844 | |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 845 | if (skip_on_failure && low_pfn >= next_skip_pfn) { |
| 846 | /* |
| 847 | * We have isolated all migration candidates in the |
| 848 | * previous order-aligned block, and did not skip it due |
| 849 | * to failure. We should migrate the pages now and |
| 850 | * hopefully succeed compaction. |
| 851 | */ |
| 852 | if (nr_isolated) |
| 853 | break; |
| 854 | |
| 855 | /* |
| 856 | * We failed to isolate in the previous order-aligned |
| 857 | * block. Set the new boundary to the end of the |
| 858 | * current block. Note we can't simply increase |
| 859 | * next_skip_pfn by 1 << order, as low_pfn might have |
| 860 | * been incremented by a higher number due to skipping |
| 861 | * a compound or a high-order buddy page in the |
| 862 | * previous loop iteration. |
| 863 | */ |
| 864 | next_skip_pfn = block_end_pfn(low_pfn, cc->order); |
| 865 | } |
| 866 | |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 867 | /* |
| 868 | * Periodically drop the lock (if held) regardless of its |
Mel Gorman | 670105a | 2019-08-02 21:48:51 -0700 | [diff] [blame] | 869 | * contention, to give chance to IRQs. Abort completely if |
| 870 | * a fatal signal is pending. |
Vlastimil Babka | 8b44d27 | 2014-10-09 15:27:16 -0700 | [diff] [blame] | 871 | */ |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 872 | if (!(low_pfn % SWAP_CLUSTER_MAX)) { |
| 873 | if (locked) { |
| 874 | unlock_page_lruvec_irqrestore(locked, flags); |
| 875 | locked = NULL; |
| 876 | } |
| 877 | |
| 878 | if (fatal_signal_pending(current)) { |
| 879 | cc->contended = true; |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 880 | ret = -EINTR; |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 881 | |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 882 | goto fatal_pending; |
| 883 | } |
| 884 | |
| 885 | cond_resched(); |
Mel Gorman | 670105a | 2019-08-02 21:48:51 -0700 | [diff] [blame] | 886 | } |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 887 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 888 | if (!pfn_valid_within(low_pfn)) |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 889 | goto isolate_fail; |
Mel Gorman | b7aba69 | 2011-01-13 15:45:54 -0800 | [diff] [blame] | 890 | nr_scanned++; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 891 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 892 | page = pfn_to_page(low_pfn); |
Mel Gorman | dc90860 | 2012-02-08 17:13:38 -0800 | [diff] [blame] | 893 | |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 894 | /* |
| 895 | * Check if the pageblock has already been marked skipped. |
| 896 | * Only the aligned PFN is checked as the caller isolates |
| 897 | * COMPACT_CLUSTER_MAX at a time so the second call must |
| 898 | * not falsely conclude that the block should be skipped. |
| 899 | */ |
| 900 | if (!valid_page && IS_ALIGNED(low_pfn, pageblock_nr_pages)) { |
| 901 | if (!cc->ignore_skip_hint && get_pageblock_skip(page)) { |
| 902 | low_pfn = end_pfn; |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 903 | page = NULL; |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 904 | goto isolate_abort; |
| 905 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 906 | valid_page = page; |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 907 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 908 | |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 909 | if (PageHuge(page) && cc->alloc_contig) { |
Oscar Salvador | ae37c7f | 2021-05-04 18:35:29 -0700 | [diff] [blame] | 910 | ret = isolate_or_dissolve_huge_page(page, &cc->migratepages); |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 911 | |
| 912 | /* |
| 913 | * Fail isolation in case isolate_or_dissolve_huge_page() |
| 914 | * reports an error. In case of -ENOMEM, abort right away. |
| 915 | */ |
| 916 | if (ret < 0) { |
| 917 | /* Do not report -EBUSY down the chain */ |
| 918 | if (ret == -EBUSY) |
| 919 | ret = 0; |
| 920 | low_pfn += (1UL << compound_order(page)) - 1; |
| 921 | goto isolate_fail; |
| 922 | } |
| 923 | |
Oscar Salvador | ae37c7f | 2021-05-04 18:35:29 -0700 | [diff] [blame] | 924 | if (PageHuge(page)) { |
| 925 | /* |
| 926 | * Hugepage was successfully isolated and placed |
| 927 | * on the cc->migratepages list. |
| 928 | */ |
| 929 | low_pfn += compound_nr(page) - 1; |
| 930 | goto isolate_success_no_list; |
| 931 | } |
| 932 | |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 933 | /* |
| 934 | * Ok, the hugepage was dissolved. Now these pages are |
| 935 | * Buddy and cannot be re-allocated because they are |
| 936 | * isolated. Fall-through as the check below handles |
| 937 | * Buddy pages. |
| 938 | */ |
| 939 | } |
| 940 | |
Mel Gorman | 6c14466 | 2014-01-23 15:53:38 -0800 | [diff] [blame] | 941 | /* |
Vlastimil Babka | 99c0fd5 | 2014-10-09 15:27:23 -0700 | [diff] [blame] | 942 | * Skip if free. We read page order here without zone lock |
| 943 | * which is generally unsafe, but the race window is small and |
| 944 | * the worst thing that can happen is that we skip some |
| 945 | * potential isolation targets. |
Mel Gorman | 6c14466 | 2014-01-23 15:53:38 -0800 | [diff] [blame] | 946 | */ |
Vlastimil Babka | 99c0fd5 | 2014-10-09 15:27:23 -0700 | [diff] [blame] | 947 | if (PageBuddy(page)) { |
Matthew Wilcox (Oracle) | ab130f91 | 2020-10-15 20:10:15 -0700 | [diff] [blame] | 948 | unsigned long freepage_order = buddy_order_unsafe(page); |
Vlastimil Babka | 99c0fd5 | 2014-10-09 15:27:23 -0700 | [diff] [blame] | 949 | |
| 950 | /* |
| 951 | * Without lock, we cannot be sure that what we got is |
| 952 | * a valid page order. Consider only values in the |
| 953 | * valid order range to prevent low_pfn overflow. |
| 954 | */ |
| 955 | if (freepage_order > 0 && freepage_order < MAX_ORDER) |
| 956 | low_pfn += (1UL << freepage_order) - 1; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 957 | continue; |
Vlastimil Babka | 99c0fd5 | 2014-10-09 15:27:23 -0700 | [diff] [blame] | 958 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 959 | |
Mel Gorman | 9927af74 | 2011-01-13 15:45:59 -0800 | [diff] [blame] | 960 | /* |
Vlastimil Babka | 29c0dde | 2015-09-08 15:02:46 -0700 | [diff] [blame] | 961 | * Regardless of being on LRU, compound pages such as THP and |
Rik van Riel | 1da2f32 | 2020-04-01 21:10:31 -0700 | [diff] [blame] | 962 | * hugetlbfs are not to be compacted unless we are attempting |
| 963 | * an allocation much larger than the huge page size (eg CMA). |
| 964 | * We can potentially save a lot of iterations if we skip them |
| 965 | * at once. The check is racy, but we can consider only valid |
| 966 | * values and the only danger is skipping too much. |
Andrea Arcangeli | bc83501 | 2011-01-13 15:47:08 -0800 | [diff] [blame] | 967 | */ |
Rik van Riel | 1da2f32 | 2020-04-01 21:10:31 -0700 | [diff] [blame] | 968 | if (PageCompound(page) && !cc->alloc_contig) { |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 969 | const unsigned int order = compound_order(page); |
Vlastimil Babka | 29c0dde | 2015-09-08 15:02:46 -0700 | [diff] [blame] | 970 | |
Vlastimil Babka | d3c85ba | 2017-11-17 15:26:41 -0800 | [diff] [blame] | 971 | if (likely(order < MAX_ORDER)) |
David Rientjes | 21dc7e0 | 2017-11-17 15:26:30 -0800 | [diff] [blame] | 972 | low_pfn += (1UL << order) - 1; |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 973 | goto isolate_fail; |
Mel Gorman | 2a1402aa | 2012-10-08 16:32:33 -0700 | [diff] [blame] | 974 | } |
| 975 | |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 976 | /* |
| 977 | * Check may be lockless but that's ok as we recheck later. |
| 978 | * It's possible to migrate LRU and non-lru movable pages. |
| 979 | * Skip any other type of page |
| 980 | */ |
| 981 | if (!PageLRU(page)) { |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 982 | /* |
| 983 | * __PageMovable can return false positive so we need |
| 984 | * to verify it under page_lock. |
| 985 | */ |
| 986 | if (unlikely(__PageMovable(page)) && |
| 987 | !PageIsolated(page)) { |
| 988 | if (locked) { |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 989 | unlock_page_lruvec_irqrestore(locked, flags); |
| 990 | locked = NULL; |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 991 | } |
| 992 | |
Yisheng Xie | 9e5bcd6 | 2017-02-24 14:57:29 -0800 | [diff] [blame] | 993 | if (!isolate_movable_page(page, isolate_mode)) |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 994 | goto isolate_success; |
| 995 | } |
| 996 | |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 997 | goto isolate_fail; |
Minchan Kim | bda807d | 2016-07-26 15:23:05 -0700 | [diff] [blame] | 998 | } |
Vlastimil Babka | 29c0dde | 2015-09-08 15:02:46 -0700 | [diff] [blame] | 999 | |
David Rientjes | 119d6d5 | 2014-04-03 14:48:00 -0700 | [diff] [blame] | 1000 | /* |
| 1001 | * Migration will fail if an anonymous page is pinned in memory, |
| 1002 | * so avoid taking lru_lock and isolating it unnecessarily in an |
| 1003 | * admittedly racy check. |
| 1004 | */ |
| 1005 | if (!page_mapping(page) && |
| 1006 | page_count(page) > page_mapcount(page)) |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1007 | goto isolate_fail; |
David Rientjes | 119d6d5 | 2014-04-03 14:48:00 -0700 | [diff] [blame] | 1008 | |
Michal Hocko | 73e64c51 | 2016-12-14 15:04:07 -0800 | [diff] [blame] | 1009 | /* |
| 1010 | * Only allow to migrate anonymous pages in GFP_NOFS context |
| 1011 | * because those do not depend on fs locks. |
| 1012 | */ |
| 1013 | if (!(cc->gfp_mask & __GFP_FS) && page_mapping(page)) |
| 1014 | goto isolate_fail; |
| 1015 | |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1016 | /* |
| 1017 | * Be careful not to clear PageLRU until after we're |
| 1018 | * sure the page is not being freed elsewhere -- the |
| 1019 | * page release code relies on it. |
| 1020 | */ |
| 1021 | if (unlikely(!get_page_unless_zero(page))) |
| 1022 | goto isolate_fail; |
| 1023 | |
Alex Shi | c2135f7 | 2021-02-24 12:08:01 -0800 | [diff] [blame] | 1024 | if (!__isolate_lru_page_prepare(page, isolate_mode)) |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1025 | goto isolate_fail_put; |
| 1026 | |
| 1027 | /* Try isolate the page */ |
| 1028 | if (!TestClearPageLRU(page)) |
| 1029 | goto isolate_fail_put; |
| 1030 | |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 1031 | lruvec = mem_cgroup_page_lruvec(page, pgdat); |
| 1032 | |
Vlastimil Babka | 69b7189 | 2014-10-09 15:27:18 -0700 | [diff] [blame] | 1033 | /* If we already hold the lock, we can skip some rechecking */ |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 1034 | if (lruvec != locked) { |
| 1035 | if (locked) |
| 1036 | unlock_page_lruvec_irqrestore(locked, flags); |
| 1037 | |
| 1038 | compact_lock_irqsave(&lruvec->lru_lock, &flags, cc); |
| 1039 | locked = lruvec; |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 1040 | |
| 1041 | lruvec_memcg_debug(lruvec, page); |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 1042 | |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 1043 | /* Try get exclusive access under lock */ |
| 1044 | if (!skip_updated) { |
| 1045 | skip_updated = true; |
| 1046 | if (test_and_set_skip(cc, page, low_pfn)) |
| 1047 | goto isolate_abort; |
| 1048 | } |
Mel Gorman | 2a1402aa | 2012-10-08 16:32:33 -0700 | [diff] [blame] | 1049 | |
Vlastimil Babka | 29c0dde | 2015-09-08 15:02:46 -0700 | [diff] [blame] | 1050 | /* |
| 1051 | * Page become compound since the non-locked check, |
| 1052 | * and it's on LRU. It can only be a THP so the order |
| 1053 | * is safe to read and it's 0 for tail pages. |
| 1054 | */ |
Rik van Riel | 1da2f32 | 2020-04-01 21:10:31 -0700 | [diff] [blame] | 1055 | if (unlikely(PageCompound(page) && !cc->alloc_contig)) { |
Matthew Wilcox (Oracle) | d8c6546 | 2019-09-23 15:34:30 -0700 | [diff] [blame] | 1056 | low_pfn += compound_nr(page) - 1; |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1057 | SetPageLRU(page); |
| 1058 | goto isolate_fail_put; |
Vlastimil Babka | 69b7189 | 2014-10-09 15:27:18 -0700 | [diff] [blame] | 1059 | } |
Alex Shi | d99fd5f | 2021-02-24 12:09:25 -0800 | [diff] [blame] | 1060 | } |
Hugh Dickins | fa9add6 | 2012-05-29 15:07:09 -0700 | [diff] [blame] | 1061 | |
Rik van Riel | 1da2f32 | 2020-04-01 21:10:31 -0700 | [diff] [blame] | 1062 | /* The whole page is taken off the LRU; skip the tail pages. */ |
| 1063 | if (PageCompound(page)) |
| 1064 | low_pfn += compound_nr(page) - 1; |
Andrea Arcangeli | bc83501 | 2011-01-13 15:47:08 -0800 | [diff] [blame] | 1065 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1066 | /* Successfully isolated */ |
Yu Zhao | 46ae6b2 | 2021-02-24 12:08:25 -0800 | [diff] [blame] | 1067 | del_page_from_lru_list(page, lruvec); |
Rik van Riel | 1da2f32 | 2020-04-01 21:10:31 -0700 | [diff] [blame] | 1068 | mod_node_page_state(page_pgdat(page), |
Huang Ying | 9de4f22 | 2020-04-06 20:04:41 -0700 | [diff] [blame] | 1069 | NR_ISOLATED_ANON + page_is_file_lru(page), |
Matthew Wilcox (Oracle) | 6c35784 | 2020-08-14 17:30:37 -0700 | [diff] [blame] | 1070 | thp_nr_pages(page)); |
Joonsoo Kim | b6c7501 | 2014-04-07 15:37:07 -0700 | [diff] [blame] | 1071 | |
| 1072 | isolate_success: |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1073 | list_add(&page->lru, &cc->migratepages); |
Oscar Salvador | ae37c7f | 2021-05-04 18:35:29 -0700 | [diff] [blame] | 1074 | isolate_success_no_list: |
Zi Yan | 3893586 | 2020-11-13 22:51:40 -0800 | [diff] [blame] | 1075 | cc->nr_migratepages += compound_nr(page); |
| 1076 | nr_isolated += compound_nr(page); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1077 | |
Mel Gorman | 804d312 | 2019-03-05 15:45:07 -0800 | [diff] [blame] | 1078 | /* |
| 1079 | * Avoid isolating too much unless this block is being |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 1080 | * rescanned (e.g. dirty/writeback pages, parallel allocation) |
| 1081 | * or a lock is contended. For contention, isolate quickly to |
| 1082 | * potentially remove one source of contention. |
Mel Gorman | 804d312 | 2019-03-05 15:45:07 -0800 | [diff] [blame] | 1083 | */ |
Zi Yan | 3893586 | 2020-11-13 22:51:40 -0800 | [diff] [blame] | 1084 | if (cc->nr_migratepages >= COMPACT_CLUSTER_MAX && |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 1085 | !cc->rescan && !cc->contended) { |
Hillf Danton | 31b8384 | 2012-01-10 15:07:59 -0800 | [diff] [blame] | 1086 | ++low_pfn; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1087 | break; |
Hillf Danton | 31b8384 | 2012-01-10 15:07:59 -0800 | [diff] [blame] | 1088 | } |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1089 | |
| 1090 | continue; |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1091 | |
| 1092 | isolate_fail_put: |
| 1093 | /* Avoid potential deadlock in freeing page under lru_lock */ |
| 1094 | if (locked) { |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 1095 | unlock_page_lruvec_irqrestore(locked, flags); |
| 1096 | locked = NULL; |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1097 | } |
| 1098 | put_page(page); |
| 1099 | |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1100 | isolate_fail: |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 1101 | if (!skip_on_failure && ret != -ENOMEM) |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1102 | continue; |
| 1103 | |
| 1104 | /* |
| 1105 | * We have isolated some pages, but then failed. Release them |
| 1106 | * instead of migrating, as we cannot form the cc->order buddy |
| 1107 | * page anyway. |
| 1108 | */ |
| 1109 | if (nr_isolated) { |
| 1110 | if (locked) { |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 1111 | unlock_page_lruvec_irqrestore(locked, flags); |
| 1112 | locked = NULL; |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1113 | } |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1114 | putback_movable_pages(&cc->migratepages); |
| 1115 | cc->nr_migratepages = 0; |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 1116 | nr_isolated = 0; |
| 1117 | } |
| 1118 | |
| 1119 | if (low_pfn < next_skip_pfn) { |
| 1120 | low_pfn = next_skip_pfn - 1; |
| 1121 | /* |
| 1122 | * The check near the loop beginning would have updated |
| 1123 | * next_skip_pfn too, but this is a bit simpler. |
| 1124 | */ |
| 1125 | next_skip_pfn += 1UL << cc->order; |
| 1126 | } |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 1127 | |
| 1128 | if (ret == -ENOMEM) |
| 1129 | break; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1130 | } |
| 1131 | |
Vlastimil Babka | 99c0fd5 | 2014-10-09 15:27:23 -0700 | [diff] [blame] | 1132 | /* |
| 1133 | * The PageBuddy() check could have potentially brought us outside |
| 1134 | * the range to be scanned. |
| 1135 | */ |
| 1136 | if (unlikely(low_pfn > end_pfn)) |
| 1137 | low_pfn = end_pfn; |
| 1138 | |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1139 | page = NULL; |
| 1140 | |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 1141 | isolate_abort: |
Mel Gorman | c67fe37 | 2012-08-21 16:16:17 -0700 | [diff] [blame] | 1142 | if (locked) |
Alex Shi | 6168d0d | 2020-12-15 12:34:29 -0800 | [diff] [blame] | 1143 | unlock_page_lruvec_irqrestore(locked, flags); |
Alex Shi | 9df4131 | 2020-12-15 12:34:20 -0800 | [diff] [blame] | 1144 | if (page) { |
| 1145 | SetPageLRU(page); |
| 1146 | put_page(page); |
| 1147 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1148 | |
Vlastimil Babka | 50b5b09 | 2014-01-21 15:51:10 -0800 | [diff] [blame] | 1149 | /* |
Mel Gorman | 804d312 | 2019-03-05 15:45:07 -0800 | [diff] [blame] | 1150 | * Updated the cached scanner pfn once the pageblock has been scanned |
| 1151 | * Pages will either be migrated in which case there is no point |
| 1152 | * scanning in the near future or migration failed in which case the |
| 1153 | * failure reason may persist. The block is marked for skipping if |
| 1154 | * there were no pages isolated in the block or if the block is |
| 1155 | * rescanned twice in a row. |
Vlastimil Babka | 50b5b09 | 2014-01-21 15:51:10 -0800 | [diff] [blame] | 1156 | */ |
Mel Gorman | 804d312 | 2019-03-05 15:45:07 -0800 | [diff] [blame] | 1157 | if (low_pfn == end_pfn && (!nr_isolated || cc->rescan)) { |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 1158 | if (valid_page && !skip_updated) |
| 1159 | set_pageblock_skip(valid_page); |
| 1160 | update_cached_migrate(cc, low_pfn); |
| 1161 | } |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 1162 | |
Joonsoo Kim | e34d85f | 2015-02-11 15:27:04 -0800 | [diff] [blame] | 1163 | trace_mm_compaction_isolate_migratepages(start_pfn, low_pfn, |
| 1164 | nr_scanned, nr_isolated); |
Mel Gorman | b7aba69 | 2011-01-13 15:45:54 -0800 | [diff] [blame] | 1165 | |
Mel Gorman | 670105a | 2019-08-02 21:48:51 -0700 | [diff] [blame] | 1166 | fatal_pending: |
David Rientjes | 7f354a5 | 2017-02-22 15:44:50 -0800 | [diff] [blame] | 1167 | cc->total_migrate_scanned += nr_scanned; |
Mel Gorman | 397487d | 2012-10-19 12:00:10 +0100 | [diff] [blame] | 1168 | if (nr_isolated) |
Minchan Kim | 010fc29 | 2012-12-20 15:05:06 -0800 | [diff] [blame] | 1169 | count_compact_events(COMPACTISOLATED, nr_isolated); |
Mel Gorman | 397487d | 2012-10-19 12:00:10 +0100 | [diff] [blame] | 1170 | |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1171 | cc->migrate_pfn = low_pfn; |
| 1172 | |
| 1173 | return ret; |
Michal Nazarewicz | 2fe86e0 | 2012-01-30 13:16:26 +0100 | [diff] [blame] | 1174 | } |
| 1175 | |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1176 | /** |
| 1177 | * isolate_migratepages_range() - isolate migrate-able pages in a PFN range |
| 1178 | * @cc: Compaction control structure. |
| 1179 | * @start_pfn: The first PFN to start isolating. |
| 1180 | * @end_pfn: The one-past-last PFN. |
| 1181 | * |
Oscar Salvador | 369fa22 | 2021-05-04 18:35:26 -0700 | [diff] [blame] | 1182 | * Returns -EAGAIN when contented, -EINTR in case of a signal pending, -ENOMEM |
| 1183 | * in case we could not allocate a page, or 0. |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1184 | */ |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1185 | int |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1186 | isolate_migratepages_range(struct compact_control *cc, unsigned long start_pfn, |
| 1187 | unsigned long end_pfn) |
| 1188 | { |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1189 | unsigned long pfn, block_start_pfn, block_end_pfn; |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1190 | int ret = 0; |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1191 | |
| 1192 | /* Scan block by block. First and last block may be incomplete */ |
| 1193 | pfn = start_pfn; |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 1194 | block_start_pfn = pageblock_start_pfn(pfn); |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1195 | if (block_start_pfn < cc->zone->zone_start_pfn) |
| 1196 | block_start_pfn = cc->zone->zone_start_pfn; |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 1197 | block_end_pfn = pageblock_end_pfn(pfn); |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1198 | |
| 1199 | for (; pfn < end_pfn; pfn = block_end_pfn, |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1200 | block_start_pfn = block_end_pfn, |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1201 | block_end_pfn += pageblock_nr_pages) { |
| 1202 | |
| 1203 | block_end_pfn = min(block_end_pfn, end_pfn); |
| 1204 | |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1205 | if (!pageblock_pfn_to_page(block_start_pfn, |
| 1206 | block_end_pfn, cc->zone)) |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1207 | continue; |
| 1208 | |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1209 | ret = isolate_migratepages_block(cc, pfn, block_end_pfn, |
| 1210 | ISOLATE_UNEVICTABLE); |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1211 | |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1212 | if (ret) |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1213 | break; |
Joonsoo Kim | 6ea41c0 | 2014-10-29 14:50:20 -0700 | [diff] [blame] | 1214 | |
Zi Yan | 3893586 | 2020-11-13 22:51:40 -0800 | [diff] [blame] | 1215 | if (cc->nr_migratepages >= COMPACT_CLUSTER_MAX) |
Joonsoo Kim | 6ea41c0 | 2014-10-29 14:50:20 -0700 | [diff] [blame] | 1216 | break; |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1217 | } |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1218 | |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1219 | return ret; |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1220 | } |
| 1221 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1222 | #endif /* CONFIG_COMPACTION || CONFIG_CMA */ |
| 1223 | #ifdef CONFIG_COMPACTION |
Andrew Morton | 018e9a4 | 2015-04-15 16:15:20 -0700 | [diff] [blame] | 1224 | |
Vlastimil Babka | b682deb | 2017-05-08 15:54:43 -0700 | [diff] [blame] | 1225 | static bool suitable_migration_source(struct compact_control *cc, |
| 1226 | struct page *page) |
| 1227 | { |
Vlastimil Babka | 282722b | 2017-05-08 15:54:49 -0700 | [diff] [blame] | 1228 | int block_mt; |
| 1229 | |
Mel Gorman | 9bebefd | 2019-03-05 15:45:14 -0800 | [diff] [blame] | 1230 | if (pageblock_skip_persistent(page)) |
| 1231 | return false; |
| 1232 | |
Vlastimil Babka | 282722b | 2017-05-08 15:54:49 -0700 | [diff] [blame] | 1233 | if ((cc->mode != MIGRATE_ASYNC) || !cc->direct_compaction) |
Vlastimil Babka | b682deb | 2017-05-08 15:54:43 -0700 | [diff] [blame] | 1234 | return true; |
| 1235 | |
Vlastimil Babka | 282722b | 2017-05-08 15:54:49 -0700 | [diff] [blame] | 1236 | block_mt = get_pageblock_migratetype(page); |
| 1237 | |
| 1238 | if (cc->migratetype == MIGRATE_MOVABLE) |
| 1239 | return is_migrate_movable(block_mt); |
| 1240 | else |
| 1241 | return block_mt == cc->migratetype; |
Vlastimil Babka | b682deb | 2017-05-08 15:54:43 -0700 | [diff] [blame] | 1242 | } |
| 1243 | |
Andrew Morton | 018e9a4 | 2015-04-15 16:15:20 -0700 | [diff] [blame] | 1244 | /* Returns true if the page is within a block suitable for migration to */ |
Vlastimil Babka | 9f7e338 | 2016-10-07 17:00:37 -0700 | [diff] [blame] | 1245 | static bool suitable_migration_target(struct compact_control *cc, |
| 1246 | struct page *page) |
Andrew Morton | 018e9a4 | 2015-04-15 16:15:20 -0700 | [diff] [blame] | 1247 | { |
| 1248 | /* If the page is a large free page, then disallow migration */ |
| 1249 | if (PageBuddy(page)) { |
| 1250 | /* |
| 1251 | * We are checking page_order without zone->lock taken. But |
| 1252 | * the only small danger is that we skip a potentially suitable |
| 1253 | * pageblock, so it's not worth to check order for valid range. |
| 1254 | */ |
Matthew Wilcox (Oracle) | ab130f91 | 2020-10-15 20:10:15 -0700 | [diff] [blame] | 1255 | if (buddy_order_unsafe(page) >= pageblock_order) |
Andrew Morton | 018e9a4 | 2015-04-15 16:15:20 -0700 | [diff] [blame] | 1256 | return false; |
| 1257 | } |
| 1258 | |
Yisheng Xie | 1ef36db | 2017-05-03 14:53:54 -0700 | [diff] [blame] | 1259 | if (cc->ignore_block_suitable) |
| 1260 | return true; |
| 1261 | |
Andrew Morton | 018e9a4 | 2015-04-15 16:15:20 -0700 | [diff] [blame] | 1262 | /* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */ |
Vlastimil Babka | b682deb | 2017-05-08 15:54:43 -0700 | [diff] [blame] | 1263 | if (is_migrate_movable(get_pageblock_migratetype(page))) |
Andrew Morton | 018e9a4 | 2015-04-15 16:15:20 -0700 | [diff] [blame] | 1264 | return true; |
| 1265 | |
| 1266 | /* Otherwise skip the block */ |
| 1267 | return false; |
| 1268 | } |
| 1269 | |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1270 | static inline unsigned int |
| 1271 | freelist_scan_limit(struct compact_control *cc) |
| 1272 | { |
Qian Cai | dd7ef7b | 2019-05-13 17:17:38 -0700 | [diff] [blame] | 1273 | unsigned short shift = BITS_PER_LONG - 1; |
| 1274 | |
| 1275 | return (COMPACT_CLUSTER_MAX >> min(shift, cc->fast_search_fail)) + 1; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1276 | } |
| 1277 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1278 | /* |
Vlastimil Babka | f2849aa | 2015-09-08 15:02:36 -0700 | [diff] [blame] | 1279 | * Test whether the free scanner has reached the same or lower pageblock than |
| 1280 | * the migration scanner, and compaction should thus terminate. |
| 1281 | */ |
| 1282 | static inline bool compact_scanners_met(struct compact_control *cc) |
| 1283 | { |
| 1284 | return (cc->free_pfn >> pageblock_order) |
| 1285 | <= (cc->migrate_pfn >> pageblock_order); |
| 1286 | } |
| 1287 | |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1288 | /* |
| 1289 | * Used when scanning for a suitable migration target which scans freelists |
| 1290 | * in reverse. Reorders the list such as the unscanned pages are scanned |
| 1291 | * first on the next iteration of the free scanner |
| 1292 | */ |
| 1293 | static void |
| 1294 | move_freelist_head(struct list_head *freelist, struct page *freepage) |
| 1295 | { |
| 1296 | LIST_HEAD(sublist); |
| 1297 | |
| 1298 | if (!list_is_last(freelist, &freepage->lru)) { |
| 1299 | list_cut_before(&sublist, freelist, &freepage->lru); |
| 1300 | if (!list_empty(&sublist)) |
| 1301 | list_splice_tail(&sublist, freelist); |
| 1302 | } |
| 1303 | } |
| 1304 | |
| 1305 | /* |
| 1306 | * Similar to move_freelist_head except used by the migration scanner |
| 1307 | * when scanning forward. It's possible for these list operations to |
| 1308 | * move against each other if they search the free list exactly in |
| 1309 | * lockstep. |
| 1310 | */ |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1311 | static void |
| 1312 | move_freelist_tail(struct list_head *freelist, struct page *freepage) |
| 1313 | { |
| 1314 | LIST_HEAD(sublist); |
| 1315 | |
| 1316 | if (!list_is_first(freelist, &freepage->lru)) { |
| 1317 | list_cut_position(&sublist, freelist, &freepage->lru); |
| 1318 | if (!list_empty(&sublist)) |
| 1319 | list_splice_tail(&sublist, freelist); |
| 1320 | } |
| 1321 | } |
| 1322 | |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1323 | static void |
| 1324 | fast_isolate_around(struct compact_control *cc, unsigned long pfn, unsigned long nr_isolated) |
| 1325 | { |
| 1326 | unsigned long start_pfn, end_pfn; |
Vlastimil Babka | 6e2b704 | 2021-02-24 12:09:39 -0800 | [diff] [blame] | 1327 | struct page *page; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1328 | |
| 1329 | /* Do not search around if there are enough pages already */ |
| 1330 | if (cc->nr_freepages >= cc->nr_migratepages) |
| 1331 | return; |
| 1332 | |
| 1333 | /* Minimise scanning during async compaction */ |
| 1334 | if (cc->direct_compaction && cc->mode == MIGRATE_ASYNC) |
| 1335 | return; |
| 1336 | |
| 1337 | /* Pageblock boundaries */ |
Vlastimil Babka | 6e2b704 | 2021-02-24 12:09:39 -0800 | [diff] [blame] | 1338 | start_pfn = max(pageblock_start_pfn(pfn), cc->zone->zone_start_pfn); |
| 1339 | end_pfn = min(pageblock_end_pfn(pfn), zone_end_pfn(cc->zone)); |
| 1340 | |
| 1341 | page = pageblock_pfn_to_page(start_pfn, end_pfn, cc->zone); |
| 1342 | if (!page) |
| 1343 | return; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1344 | |
| 1345 | /* Scan before */ |
| 1346 | if (start_pfn != pfn) { |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1347 | isolate_freepages_block(cc, &start_pfn, pfn, &cc->freepages, 1, false); |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1348 | if (cc->nr_freepages >= cc->nr_migratepages) |
| 1349 | return; |
| 1350 | } |
| 1351 | |
| 1352 | /* Scan after */ |
| 1353 | start_pfn = pfn + nr_isolated; |
Mel Gorman | 60fce36 | 2019-05-17 14:31:41 -0700 | [diff] [blame] | 1354 | if (start_pfn < end_pfn) |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1355 | isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false); |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1356 | |
| 1357 | /* Skip this pageblock in the future as it's full or nearly full */ |
| 1358 | if (cc->nr_freepages < cc->nr_migratepages) |
| 1359 | set_pageblock_skip(page); |
| 1360 | } |
| 1361 | |
Mel Gorman | dbe2d4e | 2019-03-05 15:45:31 -0800 | [diff] [blame] | 1362 | /* Search orders in round-robin fashion */ |
| 1363 | static int next_search_order(struct compact_control *cc, int order) |
| 1364 | { |
| 1365 | order--; |
| 1366 | if (order < 0) |
| 1367 | order = cc->order - 1; |
| 1368 | |
| 1369 | /* Search wrapped around? */ |
| 1370 | if (order == cc->search_order) { |
| 1371 | cc->search_order--; |
| 1372 | if (cc->search_order < 0) |
| 1373 | cc->search_order = cc->order - 1; |
| 1374 | return -1; |
| 1375 | } |
| 1376 | |
| 1377 | return order; |
| 1378 | } |
| 1379 | |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1380 | static unsigned long |
| 1381 | fast_isolate_freepages(struct compact_control *cc) |
| 1382 | { |
| 1383 | unsigned int limit = min(1U, freelist_scan_limit(cc) >> 1); |
| 1384 | unsigned int nr_scanned = 0; |
Rokudo Yan | 74e2148 | 2021-02-04 18:32:20 -0800 | [diff] [blame] | 1385 | unsigned long low_pfn, min_pfn, highest = 0; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1386 | unsigned long nr_isolated = 0; |
| 1387 | unsigned long distance; |
| 1388 | struct page *page = NULL; |
| 1389 | bool scan_start = false; |
| 1390 | int order; |
| 1391 | |
| 1392 | /* Full compaction passes in a negative order */ |
| 1393 | if (cc->order <= 0) |
| 1394 | return cc->free_pfn; |
| 1395 | |
| 1396 | /* |
| 1397 | * If starting the scan, use a deeper search and use the highest |
| 1398 | * PFN found if a suitable one is not found. |
| 1399 | */ |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 1400 | if (cc->free_pfn >= cc->zone->compact_init_free_pfn) { |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1401 | limit = pageblock_nr_pages >> 1; |
| 1402 | scan_start = true; |
| 1403 | } |
| 1404 | |
| 1405 | /* |
| 1406 | * Preferred point is in the top quarter of the scan space but take |
| 1407 | * a pfn from the top half if the search is problematic. |
| 1408 | */ |
| 1409 | distance = (cc->free_pfn - cc->migrate_pfn); |
| 1410 | low_pfn = pageblock_start_pfn(cc->free_pfn - (distance >> 2)); |
| 1411 | min_pfn = pageblock_start_pfn(cc->free_pfn - (distance >> 1)); |
| 1412 | |
| 1413 | if (WARN_ON_ONCE(min_pfn > low_pfn)) |
| 1414 | low_pfn = min_pfn; |
| 1415 | |
Mel Gorman | dbe2d4e | 2019-03-05 15:45:31 -0800 | [diff] [blame] | 1416 | /* |
| 1417 | * Search starts from the last successful isolation order or the next |
| 1418 | * order to search after a previous failure |
| 1419 | */ |
| 1420 | cc->search_order = min_t(unsigned int, cc->order - 1, cc->search_order); |
| 1421 | |
| 1422 | for (order = cc->search_order; |
| 1423 | !page && order >= 0; |
| 1424 | order = next_search_order(cc, order)) { |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1425 | struct free_area *area = &cc->zone->free_area[order]; |
| 1426 | struct list_head *freelist; |
| 1427 | struct page *freepage; |
| 1428 | unsigned long flags; |
| 1429 | unsigned int order_scanned = 0; |
Rokudo Yan | 74e2148 | 2021-02-04 18:32:20 -0800 | [diff] [blame] | 1430 | unsigned long high_pfn = 0; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1431 | |
| 1432 | if (!area->nr_free) |
| 1433 | continue; |
| 1434 | |
| 1435 | spin_lock_irqsave(&cc->zone->lock, flags); |
| 1436 | freelist = &area->free_list[MIGRATE_MOVABLE]; |
| 1437 | list_for_each_entry_reverse(freepage, freelist, lru) { |
| 1438 | unsigned long pfn; |
| 1439 | |
| 1440 | order_scanned++; |
| 1441 | nr_scanned++; |
| 1442 | pfn = page_to_pfn(freepage); |
| 1443 | |
| 1444 | if (pfn >= highest) |
Vlastimil Babka | 6e2b704 | 2021-02-24 12:09:39 -0800 | [diff] [blame] | 1445 | highest = max(pageblock_start_pfn(pfn), |
| 1446 | cc->zone->zone_start_pfn); |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1447 | |
| 1448 | if (pfn >= low_pfn) { |
| 1449 | cc->fast_search_fail = 0; |
Mel Gorman | dbe2d4e | 2019-03-05 15:45:31 -0800 | [diff] [blame] | 1450 | cc->search_order = order; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1451 | page = freepage; |
| 1452 | break; |
| 1453 | } |
| 1454 | |
| 1455 | if (pfn >= min_pfn && pfn > high_pfn) { |
| 1456 | high_pfn = pfn; |
| 1457 | |
| 1458 | /* Shorten the scan if a candidate is found */ |
| 1459 | limit >>= 1; |
| 1460 | } |
| 1461 | |
| 1462 | if (order_scanned >= limit) |
| 1463 | break; |
| 1464 | } |
| 1465 | |
| 1466 | /* Use a minimum pfn if a preferred one was not found */ |
| 1467 | if (!page && high_pfn) { |
| 1468 | page = pfn_to_page(high_pfn); |
| 1469 | |
| 1470 | /* Update freepage for the list reorder below */ |
| 1471 | freepage = page; |
| 1472 | } |
| 1473 | |
| 1474 | /* Reorder to so a future search skips recent pages */ |
| 1475 | move_freelist_head(freelist, freepage); |
| 1476 | |
| 1477 | /* Isolate the page if available */ |
| 1478 | if (page) { |
| 1479 | if (__isolate_free_page(page, order)) { |
| 1480 | set_page_private(page, order); |
| 1481 | nr_isolated = 1 << order; |
| 1482 | cc->nr_freepages += nr_isolated; |
| 1483 | list_add_tail(&page->lru, &cc->freepages); |
| 1484 | count_compact_events(COMPACTISOLATED, nr_isolated); |
| 1485 | } else { |
| 1486 | /* If isolation fails, abort the search */ |
Qian Cai | 5b56d99 | 2019-04-04 11:54:41 +0100 | [diff] [blame] | 1487 | order = cc->search_order + 1; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1488 | page = NULL; |
| 1489 | } |
| 1490 | } |
| 1491 | |
| 1492 | spin_unlock_irqrestore(&cc->zone->lock, flags); |
| 1493 | |
| 1494 | /* |
| 1495 | * Smaller scan on next order so the total scan ig related |
| 1496 | * to freelist_scan_limit. |
| 1497 | */ |
| 1498 | if (order_scanned >= limit) |
| 1499 | limit = min(1U, limit >> 1); |
| 1500 | } |
| 1501 | |
| 1502 | if (!page) { |
| 1503 | cc->fast_search_fail++; |
| 1504 | if (scan_start) { |
| 1505 | /* |
| 1506 | * Use the highest PFN found above min. If one was |
Ethon Paul | f386775 | 2020-06-04 16:49:13 -0700 | [diff] [blame] | 1507 | * not found, be pessimistic for direct compaction |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1508 | * and use the min mark. |
| 1509 | */ |
| 1510 | if (highest) { |
| 1511 | page = pfn_to_page(highest); |
| 1512 | cc->free_pfn = highest; |
| 1513 | } else { |
Suzuki K Poulose | e577c8b | 2019-05-31 22:30:59 -0700 | [diff] [blame] | 1514 | if (cc->direct_compaction && pfn_valid(min_pfn)) { |
Baoquan He | 73a6e47 | 2020-06-03 15:57:55 -0700 | [diff] [blame] | 1515 | page = pageblock_pfn_to_page(min_pfn, |
Vlastimil Babka | 6e2b704 | 2021-02-24 12:09:39 -0800 | [diff] [blame] | 1516 | min(pageblock_end_pfn(min_pfn), |
| 1517 | zone_end_pfn(cc->zone)), |
Baoquan He | 73a6e47 | 2020-06-03 15:57:55 -0700 | [diff] [blame] | 1518 | cc->zone); |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1519 | cc->free_pfn = min_pfn; |
| 1520 | } |
| 1521 | } |
| 1522 | } |
| 1523 | } |
| 1524 | |
Mel Gorman | d097a6f | 2019-03-05 15:45:28 -0800 | [diff] [blame] | 1525 | if (highest && highest >= cc->zone->compact_cached_free_pfn) { |
| 1526 | highest -= pageblock_nr_pages; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1527 | cc->zone->compact_cached_free_pfn = highest; |
Mel Gorman | d097a6f | 2019-03-05 15:45:28 -0800 | [diff] [blame] | 1528 | } |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1529 | |
| 1530 | cc->total_free_scanned += nr_scanned; |
| 1531 | if (!page) |
| 1532 | return cc->free_pfn; |
| 1533 | |
| 1534 | low_pfn = page_to_pfn(page); |
| 1535 | fast_isolate_around(cc, low_pfn, nr_isolated); |
| 1536 | return low_pfn; |
| 1537 | } |
| 1538 | |
Vlastimil Babka | f2849aa | 2015-09-08 15:02:36 -0700 | [diff] [blame] | 1539 | /* |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1540 | * Based on information in the current compact_control, find blocks |
| 1541 | * suitable for isolating free pages from and then isolate them. |
| 1542 | */ |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1543 | static void isolate_freepages(struct compact_control *cc) |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1544 | { |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1545 | struct zone *zone = cc->zone; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1546 | struct page *page; |
Vlastimil Babka | c96b9e5 | 2014-06-04 16:07:26 -0700 | [diff] [blame] | 1547 | unsigned long block_start_pfn; /* start of current pageblock */ |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 1548 | unsigned long isolate_start_pfn; /* exact pfn we start at */ |
Vlastimil Babka | c96b9e5 | 2014-06-04 16:07:26 -0700 | [diff] [blame] | 1549 | unsigned long block_end_pfn; /* end of current pageblock */ |
| 1550 | unsigned long low_pfn; /* lowest pfn scanner is able to scan */ |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1551 | struct list_head *freelist = &cc->freepages; |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1552 | unsigned int stride; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1553 | |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1554 | /* Try a small search of the free lists for a candidate */ |
| 1555 | isolate_start_pfn = fast_isolate_freepages(cc); |
| 1556 | if (cc->nr_freepages) |
| 1557 | goto splitmap; |
| 1558 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1559 | /* |
| 1560 | * Initialise the free scanner. The starting point is where we last |
Vlastimil Babka | 49e068f | 2014-05-06 12:50:03 -0700 | [diff] [blame] | 1561 | * successfully isolated from, zone-cached value, or the end of the |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 1562 | * zone when isolating for the first time. For looping we also need |
| 1563 | * this pfn aligned down to the pageblock boundary, because we do |
Vlastimil Babka | c96b9e5 | 2014-06-04 16:07:26 -0700 | [diff] [blame] | 1564 | * block_start_pfn -= pageblock_nr_pages in the for loop. |
| 1565 | * For ending point, take care when isolating in last pageblock of a |
Randy Dunlap | a1c1dbe | 2020-08-11 18:32:49 -0700 | [diff] [blame] | 1566 | * zone which ends in the middle of a pageblock. |
Vlastimil Babka | 49e068f | 2014-05-06 12:50:03 -0700 | [diff] [blame] | 1567 | * The low boundary is the end of the pageblock the migration scanner |
| 1568 | * is using. |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1569 | */ |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 1570 | isolate_start_pfn = cc->free_pfn; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1571 | block_start_pfn = pageblock_start_pfn(isolate_start_pfn); |
Vlastimil Babka | c96b9e5 | 2014-06-04 16:07:26 -0700 | [diff] [blame] | 1572 | block_end_pfn = min(block_start_pfn + pageblock_nr_pages, |
| 1573 | zone_end_pfn(zone)); |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 1574 | low_pfn = pageblock_end_pfn(cc->migrate_pfn); |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1575 | stride = cc->mode == MIGRATE_ASYNC ? COMPACT_CLUSTER_MAX : 1; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1576 | |
| 1577 | /* |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1578 | * Isolate free pages until enough are available to migrate the |
| 1579 | * pages on cc->migratepages. We stop searching if the migrate |
| 1580 | * and free page scanners meet or enough free pages are isolated. |
| 1581 | */ |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1582 | for (; block_start_pfn >= low_pfn; |
Vlastimil Babka | c96b9e5 | 2014-06-04 16:07:26 -0700 | [diff] [blame] | 1583 | block_end_pfn = block_start_pfn, |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 1584 | block_start_pfn -= pageblock_nr_pages, |
| 1585 | isolate_start_pfn = block_start_pfn) { |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1586 | unsigned long nr_isolated; |
| 1587 | |
David Rientjes | f6ea3ad | 2013-09-30 13:45:03 -0700 | [diff] [blame] | 1588 | /* |
| 1589 | * This can iterate a massively long zone without finding any |
Mel Gorman | cb810ad | 2019-03-05 15:45:21 -0800 | [diff] [blame] | 1590 | * suitable migration targets, so periodically check resched. |
David Rientjes | f6ea3ad | 2013-09-30 13:45:03 -0700 | [diff] [blame] | 1591 | */ |
Mel Gorman | cb810ad | 2019-03-05 15:45:21 -0800 | [diff] [blame] | 1592 | if (!(block_start_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))) |
Mel Gorman | cf66f07 | 2019-03-05 15:45:24 -0800 | [diff] [blame] | 1593 | cond_resched(); |
David Rientjes | f6ea3ad | 2013-09-30 13:45:03 -0700 | [diff] [blame] | 1594 | |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 1595 | page = pageblock_pfn_to_page(block_start_pfn, block_end_pfn, |
| 1596 | zone); |
| 1597 | if (!page) |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1598 | continue; |
| 1599 | |
| 1600 | /* Check the block is suitable for migration */ |
Vlastimil Babka | 9f7e338 | 2016-10-07 17:00:37 -0700 | [diff] [blame] | 1601 | if (!suitable_migration_target(cc, page)) |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1602 | continue; |
Linus Torvalds | 68e3e92 | 2012-06-03 20:05:57 -0700 | [diff] [blame] | 1603 | |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 1604 | /* If isolation recently failed, do not retry */ |
| 1605 | if (!isolation_suitable(cc, page)) |
| 1606 | continue; |
| 1607 | |
Vlastimil Babka | e14c720 | 2014-10-09 15:27:20 -0700 | [diff] [blame] | 1608 | /* Found a block suitable for isolating free pages from. */ |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1609 | nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn, |
| 1610 | block_end_pfn, freelist, stride, false); |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1611 | |
Mel Gorman | d097a6f | 2019-03-05 15:45:28 -0800 | [diff] [blame] | 1612 | /* Update the skip hint if the full pageblock was scanned */ |
| 1613 | if (isolate_start_pfn == block_end_pfn) |
| 1614 | update_pageblock_skip(cc, page, block_start_pfn); |
| 1615 | |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 1616 | /* Are enough freepages isolated? */ |
| 1617 | if (cc->nr_freepages >= cc->nr_migratepages) { |
David Rientjes | a46cbf3 | 2016-07-14 12:06:50 -0700 | [diff] [blame] | 1618 | if (isolate_start_pfn >= block_end_pfn) { |
| 1619 | /* |
| 1620 | * Restart at previous pageblock if more |
| 1621 | * freepages can be isolated next time. |
| 1622 | */ |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1623 | isolate_start_pfn = |
| 1624 | block_start_pfn - pageblock_nr_pages; |
David Rientjes | a46cbf3 | 2016-07-14 12:06:50 -0700 | [diff] [blame] | 1625 | } |
Vlastimil Babka | be97657 | 2014-06-04 16:10:41 -0700 | [diff] [blame] | 1626 | break; |
David Rientjes | a46cbf3 | 2016-07-14 12:06:50 -0700 | [diff] [blame] | 1627 | } else if (isolate_start_pfn < block_end_pfn) { |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1628 | /* |
David Rientjes | a46cbf3 | 2016-07-14 12:06:50 -0700 | [diff] [blame] | 1629 | * If isolation failed early, do not continue |
| 1630 | * needlessly. |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1631 | */ |
David Rientjes | a46cbf3 | 2016-07-14 12:06:50 -0700 | [diff] [blame] | 1632 | break; |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1633 | } |
Mel Gorman | 4fca973 | 2019-03-05 15:45:34 -0800 | [diff] [blame] | 1634 | |
| 1635 | /* Adjust stride depending on isolation */ |
| 1636 | if (nr_isolated) { |
| 1637 | stride = 1; |
| 1638 | continue; |
| 1639 | } |
| 1640 | stride = min_t(unsigned int, COMPACT_CLUSTER_MAX, stride << 1); |
Michal Nazarewicz | 2fe86e0 | 2012-01-30 13:16:26 +0100 | [diff] [blame] | 1641 | } |
| 1642 | |
Vlastimil Babka | 7ed695e | 2014-01-21 15:51:09 -0800 | [diff] [blame] | 1643 | /* |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1644 | * Record where the free scanner will restart next time. Either we |
| 1645 | * broke from the loop and set isolate_start_pfn based on the last |
| 1646 | * call to isolate_freepages_block(), or we met the migration scanner |
| 1647 | * and the loop terminated due to isolate_start_pfn < low_pfn |
Vlastimil Babka | 7ed695e | 2014-01-21 15:51:09 -0800 | [diff] [blame] | 1648 | */ |
Vlastimil Babka | f5f61a3 | 2015-09-08 15:02:39 -0700 | [diff] [blame] | 1649 | cc->free_pfn = isolate_start_pfn; |
Mel Gorman | 5a81188 | 2019-03-05 15:45:01 -0800 | [diff] [blame] | 1650 | |
| 1651 | splitmap: |
| 1652 | /* __isolate_free_page() does not map the pages */ |
| 1653 | split_map_pages(freelist); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1654 | } |
| 1655 | |
| 1656 | /* |
| 1657 | * This is a migrate-callback that "allocates" freepages by taking pages |
| 1658 | * from the isolated freelists in the block we are migrating to. |
| 1659 | */ |
| 1660 | static struct page *compaction_alloc(struct page *migratepage, |
Michal Hocko | 666feb2 | 2018-04-10 16:30:03 -0700 | [diff] [blame] | 1661 | unsigned long data) |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1662 | { |
| 1663 | struct compact_control *cc = (struct compact_control *)data; |
| 1664 | struct page *freepage; |
| 1665 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1666 | if (list_empty(&cc->freepages)) { |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 1667 | isolate_freepages(cc); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 1668 | |
| 1669 | if (list_empty(&cc->freepages)) |
| 1670 | return NULL; |
| 1671 | } |
| 1672 | |
| 1673 | freepage = list_entry(cc->freepages.next, struct page, lru); |
| 1674 | list_del(&freepage->lru); |
| 1675 | cc->nr_freepages--; |
| 1676 | |
| 1677 | return freepage; |
| 1678 | } |
| 1679 | |
| 1680 | /* |
David Rientjes | d53aea3 | 2014-06-04 16:08:26 -0700 | [diff] [blame] | 1681 | * This is a migrate-callback that "frees" freepages back to the isolated |
| 1682 | * freelist. All pages on the freelist are from the same zone, so there is no |
| 1683 | * special handling needed for NUMA. |
| 1684 | */ |
| 1685 | static void compaction_free(struct page *page, unsigned long data) |
| 1686 | { |
| 1687 | struct compact_control *cc = (struct compact_control *)data; |
| 1688 | |
| 1689 | list_add(&page->lru, &cc->freepages); |
| 1690 | cc->nr_freepages++; |
| 1691 | } |
| 1692 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1693 | /* possible outcome of isolate_migratepages */ |
| 1694 | typedef enum { |
| 1695 | ISOLATE_ABORT, /* Abort compaction now */ |
| 1696 | ISOLATE_NONE, /* No pages isolated, continue scanning */ |
| 1697 | ISOLATE_SUCCESS, /* Pages isolated, migrate */ |
| 1698 | } isolate_migrate_t; |
| 1699 | |
| 1700 | /* |
Eric B Munson | 5bbe354 | 2015-04-15 16:13:20 -0700 | [diff] [blame] | 1701 | * Allow userspace to control policy on scanning the unevictable LRU for |
| 1702 | * compactable pages. |
| 1703 | */ |
Sebastian Andrzej Siewior | 6923aa0 | 2020-04-01 21:10:42 -0700 | [diff] [blame] | 1704 | #ifdef CONFIG_PREEMPT_RT |
| 1705 | int sysctl_compact_unevictable_allowed __read_mostly = 0; |
| 1706 | #else |
Eric B Munson | 5bbe354 | 2015-04-15 16:13:20 -0700 | [diff] [blame] | 1707 | int sysctl_compact_unevictable_allowed __read_mostly = 1; |
Sebastian Andrzej Siewior | 6923aa0 | 2020-04-01 21:10:42 -0700 | [diff] [blame] | 1708 | #endif |
Eric B Munson | 5bbe354 | 2015-04-15 16:13:20 -0700 | [diff] [blame] | 1709 | |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1710 | static inline void |
| 1711 | update_fast_start_pfn(struct compact_control *cc, unsigned long pfn) |
| 1712 | { |
| 1713 | if (cc->fast_start_pfn == ULONG_MAX) |
| 1714 | return; |
| 1715 | |
| 1716 | if (!cc->fast_start_pfn) |
| 1717 | cc->fast_start_pfn = pfn; |
| 1718 | |
| 1719 | cc->fast_start_pfn = min(cc->fast_start_pfn, pfn); |
| 1720 | } |
| 1721 | |
| 1722 | static inline unsigned long |
| 1723 | reinit_migrate_pfn(struct compact_control *cc) |
| 1724 | { |
| 1725 | if (!cc->fast_start_pfn || cc->fast_start_pfn == ULONG_MAX) |
| 1726 | return cc->migrate_pfn; |
| 1727 | |
| 1728 | cc->migrate_pfn = cc->fast_start_pfn; |
| 1729 | cc->fast_start_pfn = ULONG_MAX; |
| 1730 | |
| 1731 | return cc->migrate_pfn; |
| 1732 | } |
| 1733 | |
| 1734 | /* |
| 1735 | * Briefly search the free lists for a migration source that already has |
| 1736 | * some free pages to reduce the number of pages that need migration |
| 1737 | * before a pageblock is free. |
| 1738 | */ |
| 1739 | static unsigned long fast_find_migrateblock(struct compact_control *cc) |
| 1740 | { |
| 1741 | unsigned int limit = freelist_scan_limit(cc); |
| 1742 | unsigned int nr_scanned = 0; |
| 1743 | unsigned long distance; |
| 1744 | unsigned long pfn = cc->migrate_pfn; |
| 1745 | unsigned long high_pfn; |
| 1746 | int order; |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1747 | bool found_block = false; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1748 | |
| 1749 | /* Skip hints are relied on to avoid repeats on the fast search */ |
| 1750 | if (cc->ignore_skip_hint) |
| 1751 | return pfn; |
| 1752 | |
| 1753 | /* |
| 1754 | * If the migrate_pfn is not at the start of a zone or the start |
| 1755 | * of a pageblock then assume this is a continuation of a previous |
| 1756 | * scan restarted due to COMPACT_CLUSTER_MAX. |
| 1757 | */ |
| 1758 | if (pfn != cc->zone->zone_start_pfn && pfn != pageblock_start_pfn(pfn)) |
| 1759 | return pfn; |
| 1760 | |
| 1761 | /* |
| 1762 | * For smaller orders, just linearly scan as the number of pages |
| 1763 | * to migrate should be relatively small and does not necessarily |
| 1764 | * justify freeing up a large block for a small allocation. |
| 1765 | */ |
| 1766 | if (cc->order <= PAGE_ALLOC_COSTLY_ORDER) |
| 1767 | return pfn; |
| 1768 | |
| 1769 | /* |
| 1770 | * Only allow kcompactd and direct requests for movable pages to |
| 1771 | * quickly clear out a MOVABLE pageblock for allocation. This |
| 1772 | * reduces the risk that a large movable pageblock is freed for |
| 1773 | * an unmovable/reclaimable small allocation. |
| 1774 | */ |
| 1775 | if (cc->direct_compaction && cc->migratetype != MIGRATE_MOVABLE) |
| 1776 | return pfn; |
| 1777 | |
| 1778 | /* |
| 1779 | * When starting the migration scanner, pick any pageblock within the |
| 1780 | * first half of the search space. Otherwise try and pick a pageblock |
| 1781 | * within the first eighth to reduce the chances that a migration |
| 1782 | * target later becomes a source. |
| 1783 | */ |
| 1784 | distance = (cc->free_pfn - cc->migrate_pfn) >> 1; |
| 1785 | if (cc->migrate_pfn != cc->zone->zone_start_pfn) |
| 1786 | distance >>= 2; |
| 1787 | high_pfn = pageblock_start_pfn(cc->migrate_pfn + distance); |
| 1788 | |
| 1789 | for (order = cc->order - 1; |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1790 | order >= PAGE_ALLOC_COSTLY_ORDER && !found_block && nr_scanned < limit; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1791 | order--) { |
| 1792 | struct free_area *area = &cc->zone->free_area[order]; |
| 1793 | struct list_head *freelist; |
| 1794 | unsigned long flags; |
| 1795 | struct page *freepage; |
| 1796 | |
| 1797 | if (!area->nr_free) |
| 1798 | continue; |
| 1799 | |
| 1800 | spin_lock_irqsave(&cc->zone->lock, flags); |
| 1801 | freelist = &area->free_list[MIGRATE_MOVABLE]; |
| 1802 | list_for_each_entry(freepage, freelist, lru) { |
| 1803 | unsigned long free_pfn; |
| 1804 | |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1805 | if (nr_scanned++ >= limit) { |
| 1806 | move_freelist_tail(freelist, freepage); |
| 1807 | break; |
| 1808 | } |
| 1809 | |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1810 | free_pfn = page_to_pfn(freepage); |
| 1811 | if (free_pfn < high_pfn) { |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1812 | /* |
| 1813 | * Avoid if skipped recently. Ideally it would |
| 1814 | * move to the tail but even safe iteration of |
| 1815 | * the list assumes an entry is deleted, not |
| 1816 | * reordered. |
| 1817 | */ |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1818 | if (get_pageblock_skip(freepage)) |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1819 | continue; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1820 | |
| 1821 | /* Reorder to so a future search skips recent pages */ |
| 1822 | move_freelist_tail(freelist, freepage); |
| 1823 | |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 1824 | update_fast_start_pfn(cc, free_pfn); |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1825 | pfn = pageblock_start_pfn(free_pfn); |
| 1826 | cc->fast_search_fail = 0; |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1827 | found_block = true; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1828 | set_pageblock_skip(freepage); |
| 1829 | break; |
| 1830 | } |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1831 | } |
| 1832 | spin_unlock_irqrestore(&cc->zone->lock, flags); |
| 1833 | } |
| 1834 | |
| 1835 | cc->total_migrate_scanned += nr_scanned; |
| 1836 | |
| 1837 | /* |
| 1838 | * If fast scanning failed then use a cached entry for a page block |
| 1839 | * that had free pages as the basis for starting a linear scan. |
| 1840 | */ |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1841 | if (!found_block) { |
| 1842 | cc->fast_search_fail++; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1843 | pfn = reinit_migrate_pfn(cc); |
Wonhyuk Yang | 15d28d0 | 2021-02-24 12:09:36 -0800 | [diff] [blame] | 1844 | } |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1845 | return pfn; |
| 1846 | } |
| 1847 | |
Eric B Munson | 5bbe354 | 2015-04-15 16:13:20 -0700 | [diff] [blame] | 1848 | /* |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1849 | * Isolate all pages that can be migrated from the first suitable block, |
| 1850 | * starting at the block pointed to by the migrate scanner pfn within |
| 1851 | * compact_control. |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1852 | */ |
Pengfei Li | 32aaf05 | 2019-09-23 15:36:58 -0700 | [diff] [blame] | 1853 | static isolate_migrate_t isolate_migratepages(struct compact_control *cc) |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1854 | { |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1855 | unsigned long block_start_pfn; |
| 1856 | unsigned long block_end_pfn; |
| 1857 | unsigned long low_pfn; |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1858 | struct page *page; |
| 1859 | const isolate_mode_t isolate_mode = |
Eric B Munson | 5bbe354 | 2015-04-15 16:13:20 -0700 | [diff] [blame] | 1860 | (sysctl_compact_unevictable_allowed ? ISOLATE_UNEVICTABLE : 0) | |
Hugh Dickins | 1d2047f | 2016-07-28 15:48:41 -0700 | [diff] [blame] | 1861 | (cc->mode != MIGRATE_SYNC ? ISOLATE_ASYNC_MIGRATE : 0); |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1862 | bool fast_find_block; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1863 | |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1864 | /* |
| 1865 | * Start at where we last stopped, or beginning of the zone as |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1866 | * initialized by compact_zone(). The first failure will use |
| 1867 | * the lowest PFN as the starting point for linear scanning. |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1868 | */ |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1869 | low_pfn = fast_find_migrateblock(cc); |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 1870 | block_start_pfn = pageblock_start_pfn(low_pfn); |
Pengfei Li | 32aaf05 | 2019-09-23 15:36:58 -0700 | [diff] [blame] | 1871 | if (block_start_pfn < cc->zone->zone_start_pfn) |
| 1872 | block_start_pfn = cc->zone->zone_start_pfn; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1873 | |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1874 | /* |
| 1875 | * fast_find_migrateblock marks a pageblock skipped so to avoid |
| 1876 | * the isolation_suitable check below, check whether the fast |
| 1877 | * search was successful. |
| 1878 | */ |
| 1879 | fast_find_block = low_pfn != cc->migrate_pfn && !cc->fast_search_fail; |
| 1880 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1881 | /* Only scan within a pageblock boundary */ |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 1882 | block_end_pfn = pageblock_end_pfn(low_pfn); |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1883 | |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1884 | /* |
| 1885 | * Iterate over whole pageblocks until we find the first suitable. |
| 1886 | * Do not cross the free scanner. |
| 1887 | */ |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1888 | for (; block_end_pfn <= cc->free_pfn; |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 1889 | fast_find_block = false, |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1890 | cc->migrate_pfn = low_pfn = block_end_pfn, |
Joonsoo Kim | e1409c3 | 2016-03-15 14:57:48 -0700 | [diff] [blame] | 1891 | block_start_pfn = block_end_pfn, |
| 1892 | block_end_pfn += pageblock_nr_pages) { |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1893 | |
| 1894 | /* |
| 1895 | * This can potentially iterate a massively long zone with |
| 1896 | * many pageblocks unsuitable, so periodically check if we |
Mel Gorman | cb810ad | 2019-03-05 15:45:21 -0800 | [diff] [blame] | 1897 | * need to schedule. |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1898 | */ |
Mel Gorman | cb810ad | 2019-03-05 15:45:21 -0800 | [diff] [blame] | 1899 | if (!(low_pfn % (SWAP_CLUSTER_MAX * pageblock_nr_pages))) |
Mel Gorman | cf66f07 | 2019-03-05 15:45:24 -0800 | [diff] [blame] | 1900 | cond_resched(); |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1901 | |
Pengfei Li | 32aaf05 | 2019-09-23 15:36:58 -0700 | [diff] [blame] | 1902 | page = pageblock_pfn_to_page(block_start_pfn, |
| 1903 | block_end_pfn, cc->zone); |
Vlastimil Babka | 7d49d88 | 2014-10-09 15:27:11 -0700 | [diff] [blame] | 1904 | if (!page) |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1905 | continue; |
| 1906 | |
Mel Gorman | e380beb | 2019-03-05 15:44:58 -0800 | [diff] [blame] | 1907 | /* |
| 1908 | * If isolation recently failed, do not retry. Only check the |
| 1909 | * pageblock once. COMPACT_CLUSTER_MAX causes a pageblock |
| 1910 | * to be visited multiple times. Assume skip was checked |
| 1911 | * before making it "skip" so other compaction instances do |
| 1912 | * not scan the same block. |
| 1913 | */ |
| 1914 | if (IS_ALIGNED(low_pfn, pageblock_nr_pages) && |
| 1915 | !fast_find_block && !isolation_suitable(cc, page)) |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1916 | continue; |
| 1917 | |
| 1918 | /* |
Mel Gorman | 9bebefd | 2019-03-05 15:45:14 -0800 | [diff] [blame] | 1919 | * For async compaction, also only scan in MOVABLE blocks |
| 1920 | * without huge pages. Async compaction is optimistic to see |
| 1921 | * if the minimum amount of work satisfies the allocation. |
| 1922 | * The cached PFN is updated as it's possible that all |
| 1923 | * remaining blocks between source and target are unsuitable |
| 1924 | * and the compaction scanners fail to meet. |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1925 | */ |
Mel Gorman | 9bebefd | 2019-03-05 15:45:14 -0800 | [diff] [blame] | 1926 | if (!suitable_migration_source(cc, page)) { |
| 1927 | update_cached_migrate(cc, block_end_pfn); |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1928 | continue; |
Mel Gorman | 9bebefd | 2019-03-05 15:45:14 -0800 | [diff] [blame] | 1929 | } |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1930 | |
| 1931 | /* Perform the isolation */ |
Oscar Salvador | c2ad7a1 | 2021-05-04 18:35:17 -0700 | [diff] [blame] | 1932 | if (isolate_migratepages_block(cc, low_pfn, block_end_pfn, |
| 1933 | isolate_mode)) |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1934 | return ISOLATE_ABORT; |
| 1935 | |
| 1936 | /* |
| 1937 | * Either we isolated something and proceed with migration. Or |
| 1938 | * we failed and compact_zone should decide if we should |
| 1939 | * continue or not. |
| 1940 | */ |
| 1941 | break; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1942 | } |
| 1943 | |
Vlastimil Babka | edc2ca6 | 2014-10-09 15:27:09 -0700 | [diff] [blame] | 1944 | return cc->nr_migratepages ? ISOLATE_SUCCESS : ISOLATE_NONE; |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 1945 | } |
| 1946 | |
Yaowei Bai | 21c527a | 2015-11-05 18:47:20 -0800 | [diff] [blame] | 1947 | /* |
| 1948 | * order == -1 is expected when compacting via |
| 1949 | * /proc/sys/vm/compact_memory |
| 1950 | */ |
| 1951 | static inline bool is_via_compact_memory(int order) |
| 1952 | { |
| 1953 | return order == -1; |
| 1954 | } |
| 1955 | |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 1956 | static bool kswapd_is_running(pg_data_t *pgdat) |
| 1957 | { |
| 1958 | return pgdat->kswapd && (pgdat->kswapd->state == TASK_RUNNING); |
| 1959 | } |
| 1960 | |
| 1961 | /* |
| 1962 | * A zone's fragmentation score is the external fragmentation wrt to the |
Charan Teja Reddy | 40d7e20 | 2021-02-24 12:09:32 -0800 | [diff] [blame] | 1963 | * COMPACTION_HPAGE_ORDER. It returns a value in the range [0, 100]. |
| 1964 | */ |
| 1965 | static unsigned int fragmentation_score_zone(struct zone *zone) |
| 1966 | { |
| 1967 | return extfrag_for_order(zone, COMPACTION_HPAGE_ORDER); |
| 1968 | } |
| 1969 | |
| 1970 | /* |
| 1971 | * A weighted zone's fragmentation score is the external fragmentation |
| 1972 | * wrt to the COMPACTION_HPAGE_ORDER scaled by the zone's size. It |
| 1973 | * returns a value in the range [0, 100]. |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 1974 | * |
| 1975 | * The scaling factor ensures that proactive compaction focuses on larger |
| 1976 | * zones like ZONE_NORMAL, rather than smaller, specialized zones like |
| 1977 | * ZONE_DMA32. For smaller zones, the score value remains close to zero, |
| 1978 | * and thus never exceeds the high threshold for proactive compaction. |
| 1979 | */ |
Charan Teja Reddy | 40d7e20 | 2021-02-24 12:09:32 -0800 | [diff] [blame] | 1980 | static unsigned int fragmentation_score_zone_weighted(struct zone *zone) |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 1981 | { |
| 1982 | unsigned long score; |
| 1983 | |
Charan Teja Reddy | 40d7e20 | 2021-02-24 12:09:32 -0800 | [diff] [blame] | 1984 | score = zone->present_pages * fragmentation_score_zone(zone); |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 1985 | return div64_ul(score, zone->zone_pgdat->node_present_pages + 1); |
| 1986 | } |
| 1987 | |
| 1988 | /* |
| 1989 | * The per-node proactive (background) compaction process is started by its |
| 1990 | * corresponding kcompactd thread when the node's fragmentation score |
| 1991 | * exceeds the high threshold. The compaction process remains active till |
| 1992 | * the node's score falls below the low threshold, or one of the back-off |
| 1993 | * conditions is met. |
| 1994 | */ |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 1995 | static unsigned int fragmentation_score_node(pg_data_t *pgdat) |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 1996 | { |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 1997 | unsigned int score = 0; |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 1998 | int zoneid; |
| 1999 | |
| 2000 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { |
| 2001 | struct zone *zone; |
| 2002 | |
| 2003 | zone = &pgdat->node_zones[zoneid]; |
Charan Teja Reddy | 40d7e20 | 2021-02-24 12:09:32 -0800 | [diff] [blame] | 2004 | score += fragmentation_score_zone_weighted(zone); |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2005 | } |
| 2006 | |
| 2007 | return score; |
| 2008 | } |
| 2009 | |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 2010 | static unsigned int fragmentation_score_wmark(pg_data_t *pgdat, bool low) |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2011 | { |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 2012 | unsigned int wmark_low; |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2013 | |
| 2014 | /* |
Ingo Molnar | f0953a1 | 2021-05-06 18:06:47 -0700 | [diff] [blame] | 2015 | * Cap the low watermark to avoid excessive compaction |
| 2016 | * activity in case a user sets the proactiveness tunable |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2017 | * close to 100 (maximum). |
| 2018 | */ |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 2019 | wmark_low = max(100U - sysctl_compaction_proactiveness, 5U); |
| 2020 | return low ? wmark_low : min(wmark_low + 10, 100U); |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2021 | } |
| 2022 | |
| 2023 | static bool should_proactive_compact_node(pg_data_t *pgdat) |
| 2024 | { |
| 2025 | int wmark_high; |
| 2026 | |
| 2027 | if (!sysctl_compaction_proactiveness || kswapd_is_running(pgdat)) |
| 2028 | return false; |
| 2029 | |
| 2030 | wmark_high = fragmentation_score_wmark(pgdat, false); |
| 2031 | return fragmentation_score_node(pgdat) > wmark_high; |
| 2032 | } |
| 2033 | |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2034 | static enum compact_result __compact_finished(struct compact_control *cc) |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2035 | { |
Mel Gorman | 8fb74b9 | 2013-01-11 14:32:16 -0800 | [diff] [blame] | 2036 | unsigned int order; |
Vlastimil Babka | d39773a | 2017-05-08 15:54:46 -0700 | [diff] [blame] | 2037 | const int migratetype = cc->migratetype; |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 2038 | int ret; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2039 | |
Mel Gorman | 753341a | 2012-10-08 16:32:40 -0700 | [diff] [blame] | 2040 | /* Compaction run completes if the migrate and free scanner meet */ |
Vlastimil Babka | f2849aa | 2015-09-08 15:02:36 -0700 | [diff] [blame] | 2041 | if (compact_scanners_met(cc)) { |
Vlastimil Babka | 55b7c4c | 2014-01-21 15:51:11 -0800 | [diff] [blame] | 2042 | /* Let the next compaction start anew. */ |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2043 | reset_cached_positions(cc->zone); |
Vlastimil Babka | 55b7c4c | 2014-01-21 15:51:11 -0800 | [diff] [blame] | 2044 | |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 2045 | /* |
| 2046 | * Mark that the PG_migrate_skip information should be cleared |
Vlastimil Babka | accf624 | 2016-03-17 14:18:15 -0700 | [diff] [blame] | 2047 | * by kswapd when it goes to sleep. kcompactd does not set the |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 2048 | * flag itself as the decision to be clear should be directly |
| 2049 | * based on an allocation request. |
| 2050 | */ |
Vlastimil Babka | accf624 | 2016-03-17 14:18:15 -0700 | [diff] [blame] | 2051 | if (cc->direct_compaction) |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2052 | cc->zone->compact_blockskip_flush = true; |
Mel Gorman | 6299702 | 2012-10-08 16:32:47 -0700 | [diff] [blame] | 2053 | |
Michal Hocko | c8f7de0 | 2016-05-20 16:56:47 -0700 | [diff] [blame] | 2054 | if (cc->whole_zone) |
| 2055 | return COMPACT_COMPLETE; |
| 2056 | else |
| 2057 | return COMPACT_PARTIAL_SKIPPED; |
Mel Gorman | bb13ffe | 2012-10-08 16:32:41 -0700 | [diff] [blame] | 2058 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2059 | |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2060 | if (cc->proactive_compaction) { |
| 2061 | int score, wmark_low; |
| 2062 | pg_data_t *pgdat; |
| 2063 | |
| 2064 | pgdat = cc->zone->zone_pgdat; |
| 2065 | if (kswapd_is_running(pgdat)) |
| 2066 | return COMPACT_PARTIAL_SKIPPED; |
| 2067 | |
| 2068 | score = fragmentation_score_zone(cc->zone); |
| 2069 | wmark_low = fragmentation_score_wmark(pgdat, true); |
| 2070 | |
| 2071 | if (score > wmark_low) |
| 2072 | ret = COMPACT_CONTINUE; |
| 2073 | else |
| 2074 | ret = COMPACT_SUCCESS; |
| 2075 | |
| 2076 | goto out; |
| 2077 | } |
| 2078 | |
Yaowei Bai | 21c527a | 2015-11-05 18:47:20 -0800 | [diff] [blame] | 2079 | if (is_via_compact_memory(cc->order)) |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2080 | return COMPACT_CONTINUE; |
| 2081 | |
Mel Gorman | efe771c | 2019-03-05 15:44:46 -0800 | [diff] [blame] | 2082 | /* |
| 2083 | * Always finish scanning a pageblock to reduce the possibility of |
| 2084 | * fallbacks in the future. This is particularly important when |
| 2085 | * migration source is unmovable/reclaimable but it's not worth |
| 2086 | * special casing. |
| 2087 | */ |
| 2088 | if (!IS_ALIGNED(cc->migrate_pfn, pageblock_nr_pages)) |
| 2089 | return COMPACT_CONTINUE; |
Vlastimil Babka | baf6a9a | 2017-05-08 15:54:52 -0700 | [diff] [blame] | 2090 | |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2091 | /* Direct compactor: Is a suitable page free? */ |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 2092 | ret = COMPACT_NO_SUITABLE_PAGE; |
Mel Gorman | 8fb74b9 | 2013-01-11 14:32:16 -0800 | [diff] [blame] | 2093 | for (order = cc->order; order < MAX_ORDER; order++) { |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2094 | struct free_area *area = &cc->zone->free_area[order]; |
Joonsoo Kim | 2149cda | 2015-04-14 15:45:21 -0700 | [diff] [blame] | 2095 | bool can_steal; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2096 | |
Mel Gorman | 8fb74b9 | 2013-01-11 14:32:16 -0800 | [diff] [blame] | 2097 | /* Job done if page is free of the right migratetype */ |
Dan Williams | b03641a | 2019-05-14 15:41:32 -0700 | [diff] [blame] | 2098 | if (!free_area_empty(area, migratetype)) |
Vlastimil Babka | cf37831 | 2016-10-07 16:57:41 -0700 | [diff] [blame] | 2099 | return COMPACT_SUCCESS; |
Mel Gorman | 8fb74b9 | 2013-01-11 14:32:16 -0800 | [diff] [blame] | 2100 | |
Joonsoo Kim | 2149cda | 2015-04-14 15:45:21 -0700 | [diff] [blame] | 2101 | #ifdef CONFIG_CMA |
| 2102 | /* MIGRATE_MOVABLE can fallback on MIGRATE_CMA */ |
| 2103 | if (migratetype == MIGRATE_MOVABLE && |
Dan Williams | b03641a | 2019-05-14 15:41:32 -0700 | [diff] [blame] | 2104 | !free_area_empty(area, MIGRATE_CMA)) |
Vlastimil Babka | cf37831 | 2016-10-07 16:57:41 -0700 | [diff] [blame] | 2105 | return COMPACT_SUCCESS; |
Joonsoo Kim | 2149cda | 2015-04-14 15:45:21 -0700 | [diff] [blame] | 2106 | #endif |
| 2107 | /* |
| 2108 | * Job done if allocation would steal freepages from |
| 2109 | * other migratetype buddy lists. |
| 2110 | */ |
| 2111 | if (find_suitable_fallback(area, order, migratetype, |
Vlastimil Babka | baf6a9a | 2017-05-08 15:54:52 -0700 | [diff] [blame] | 2112 | true, &can_steal) != -1) { |
| 2113 | |
| 2114 | /* movable pages are OK in any pageblock */ |
| 2115 | if (migratetype == MIGRATE_MOVABLE) |
| 2116 | return COMPACT_SUCCESS; |
| 2117 | |
| 2118 | /* |
| 2119 | * We are stealing for a non-movable allocation. Make |
| 2120 | * sure we finish compacting the current pageblock |
| 2121 | * first so it is as free as possible and we won't |
| 2122 | * have to steal another one soon. This only applies |
| 2123 | * to sync compaction, as async compaction operates |
| 2124 | * on pageblocks of the same migratetype. |
| 2125 | */ |
| 2126 | if (cc->mode == MIGRATE_ASYNC || |
| 2127 | IS_ALIGNED(cc->migrate_pfn, |
| 2128 | pageblock_nr_pages)) { |
| 2129 | return COMPACT_SUCCESS; |
| 2130 | } |
| 2131 | |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 2132 | ret = COMPACT_CONTINUE; |
| 2133 | break; |
Vlastimil Babka | baf6a9a | 2017-05-08 15:54:52 -0700 | [diff] [blame] | 2134 | } |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2135 | } |
| 2136 | |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2137 | out: |
Mel Gorman | cb2dcaf | 2019-03-05 15:45:11 -0800 | [diff] [blame] | 2138 | if (cc->contended || fatal_signal_pending(current)) |
| 2139 | ret = COMPACT_CONTENDED; |
| 2140 | |
| 2141 | return ret; |
Joonsoo Kim | 837d026 | 2015-02-11 15:27:06 -0800 | [diff] [blame] | 2142 | } |
| 2143 | |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2144 | static enum compact_result compact_finished(struct compact_control *cc) |
Joonsoo Kim | 837d026 | 2015-02-11 15:27:06 -0800 | [diff] [blame] | 2145 | { |
| 2146 | int ret; |
| 2147 | |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2148 | ret = __compact_finished(cc); |
| 2149 | trace_mm_compaction_finished(cc->zone, cc->order, ret); |
Joonsoo Kim | 837d026 | 2015-02-11 15:27:06 -0800 | [diff] [blame] | 2150 | if (ret == COMPACT_NO_SUITABLE_PAGE) |
| 2151 | ret = COMPACT_CONTINUE; |
| 2152 | |
| 2153 | return ret; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2154 | } |
| 2155 | |
Michal Hocko | ea7ab98 | 2016-05-20 16:56:38 -0700 | [diff] [blame] | 2156 | static enum compact_result __compaction_suitable(struct zone *zone, int order, |
Mel Gorman | c603844 | 2016-05-19 17:13:38 -0700 | [diff] [blame] | 2157 | unsigned int alloc_flags, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2158 | int highest_zoneidx, |
Michal Hocko | 86a294a | 2016-05-20 16:57:12 -0700 | [diff] [blame] | 2159 | unsigned long wmark_target) |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2160 | { |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2161 | unsigned long watermark; |
| 2162 | |
Yaowei Bai | 21c527a | 2015-11-05 18:47:20 -0800 | [diff] [blame] | 2163 | if (is_via_compact_memory(order)) |
Michal Hocko | 3957c77 | 2011-06-15 15:08:25 -0700 | [diff] [blame] | 2164 | return COMPACT_CONTINUE; |
| 2165 | |
Mel Gorman | a921444 | 2018-12-28 00:35:44 -0800 | [diff] [blame] | 2166 | watermark = wmark_pages(zone, alloc_flags & ALLOC_WMARK_MASK); |
Vlastimil Babka | ebff398 | 2014-12-10 15:43:22 -0800 | [diff] [blame] | 2167 | /* |
| 2168 | * If watermarks for high-order allocation are already met, there |
| 2169 | * should be no need for compaction at all. |
| 2170 | */ |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2171 | if (zone_watermark_ok(zone, order, watermark, highest_zoneidx, |
Vlastimil Babka | ebff398 | 2014-12-10 15:43:22 -0800 | [diff] [blame] | 2172 | alloc_flags)) |
Vlastimil Babka | cf37831 | 2016-10-07 16:57:41 -0700 | [diff] [blame] | 2173 | return COMPACT_SUCCESS; |
Vlastimil Babka | ebff398 | 2014-12-10 15:43:22 -0800 | [diff] [blame] | 2174 | |
Michal Hocko | 3957c77 | 2011-06-15 15:08:25 -0700 | [diff] [blame] | 2175 | /* |
Vlastimil Babka | 9861a62 | 2016-10-07 16:57:53 -0700 | [diff] [blame] | 2176 | * Watermarks for order-0 must be met for compaction to be able to |
Vlastimil Babka | 984fdba | 2016-10-07 16:57:57 -0700 | [diff] [blame] | 2177 | * isolate free pages for migration targets. This means that the |
| 2178 | * watermark and alloc_flags have to match, or be more pessimistic than |
| 2179 | * the check in __isolate_free_page(). We don't use the direct |
| 2180 | * compactor's alloc_flags, as they are not relevant for freepage |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2181 | * isolation. We however do use the direct compactor's highest_zoneidx |
| 2182 | * to skip over zones where lowmem reserves would prevent allocation |
| 2183 | * even if compaction succeeds. |
Vlastimil Babka | 8348faf | 2016-10-07 16:58:00 -0700 | [diff] [blame] | 2184 | * For costly orders, we require low watermark instead of min for |
| 2185 | * compaction to proceed to increase its chances. |
Joonsoo Kim | d883c6c | 2018-05-23 10:18:21 +0900 | [diff] [blame] | 2186 | * ALLOC_CMA is used, as pages in CMA pageblocks are considered |
| 2187 | * suitable migration targets |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2188 | */ |
Vlastimil Babka | 8348faf | 2016-10-07 16:58:00 -0700 | [diff] [blame] | 2189 | watermark = (order > PAGE_ALLOC_COSTLY_ORDER) ? |
| 2190 | low_wmark_pages(zone) : min_wmark_pages(zone); |
| 2191 | watermark += compact_gap(order); |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2192 | if (!__zone_watermark_ok(zone, 0, watermark, highest_zoneidx, |
Joonsoo Kim | d883c6c | 2018-05-23 10:18:21 +0900 | [diff] [blame] | 2193 | ALLOC_CMA, wmark_target)) |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2194 | return COMPACT_SKIPPED; |
| 2195 | |
Vlastimil Babka | cc5c9f0 | 2016-10-07 17:00:43 -0700 | [diff] [blame] | 2196 | return COMPACT_CONTINUE; |
| 2197 | } |
| 2198 | |
Hui Su | 2b1a20c | 2020-12-14 19:12:42 -0800 | [diff] [blame] | 2199 | /* |
| 2200 | * compaction_suitable: Is this suitable to run compaction on this zone now? |
| 2201 | * Returns |
| 2202 | * COMPACT_SKIPPED - If there are too few free pages for compaction |
| 2203 | * COMPACT_SUCCESS - If the allocation would succeed without compaction |
| 2204 | * COMPACT_CONTINUE - If compaction should run now |
| 2205 | */ |
Vlastimil Babka | cc5c9f0 | 2016-10-07 17:00:43 -0700 | [diff] [blame] | 2206 | enum compact_result compaction_suitable(struct zone *zone, int order, |
| 2207 | unsigned int alloc_flags, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2208 | int highest_zoneidx) |
Vlastimil Babka | cc5c9f0 | 2016-10-07 17:00:43 -0700 | [diff] [blame] | 2209 | { |
| 2210 | enum compact_result ret; |
| 2211 | int fragindex; |
| 2212 | |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2213 | ret = __compaction_suitable(zone, order, alloc_flags, highest_zoneidx, |
Vlastimil Babka | cc5c9f0 | 2016-10-07 17:00:43 -0700 | [diff] [blame] | 2214 | zone_page_state(zone, NR_FREE_PAGES)); |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2215 | /* |
| 2216 | * fragmentation index determines if allocation failures are due to |
| 2217 | * low memory or external fragmentation |
| 2218 | * |
Vlastimil Babka | ebff398 | 2014-12-10 15:43:22 -0800 | [diff] [blame] | 2219 | * index of -1000 would imply allocations might succeed depending on |
| 2220 | * watermarks, but we already failed the high-order watermark check |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2221 | * index towards 0 implies failure is due to lack of memory |
| 2222 | * index towards 1000 implies failure is due to fragmentation |
| 2223 | * |
Vlastimil Babka | 2031142 | 2016-10-07 17:00:46 -0700 | [diff] [blame] | 2224 | * Only compact if a failure would be due to fragmentation. Also |
| 2225 | * ignore fragindex for non-costly orders where the alternative to |
| 2226 | * a successful reclaim/compaction is OOM. Fragindex and the |
| 2227 | * vm.extfrag_threshold sysctl is meant as a heuristic to prevent |
| 2228 | * excessive compaction for costly orders, but it should not be at the |
| 2229 | * expense of system stability. |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2230 | */ |
Vlastimil Babka | 2031142 | 2016-10-07 17:00:46 -0700 | [diff] [blame] | 2231 | if (ret == COMPACT_CONTINUE && (order > PAGE_ALLOC_COSTLY_ORDER)) { |
Vlastimil Babka | cc5c9f0 | 2016-10-07 17:00:43 -0700 | [diff] [blame] | 2232 | fragindex = fragmentation_index(zone, order); |
| 2233 | if (fragindex >= 0 && fragindex <= sysctl_extfrag_threshold) |
| 2234 | ret = COMPACT_NOT_SUITABLE_ZONE; |
| 2235 | } |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2236 | |
Joonsoo Kim | 837d026 | 2015-02-11 15:27:06 -0800 | [diff] [blame] | 2237 | trace_mm_compaction_suitable(zone, order, ret); |
| 2238 | if (ret == COMPACT_NOT_SUITABLE_ZONE) |
| 2239 | ret = COMPACT_SKIPPED; |
| 2240 | |
| 2241 | return ret; |
| 2242 | } |
| 2243 | |
Michal Hocko | 86a294a | 2016-05-20 16:57:12 -0700 | [diff] [blame] | 2244 | bool compaction_zonelist_suitable(struct alloc_context *ac, int order, |
| 2245 | int alloc_flags) |
| 2246 | { |
| 2247 | struct zone *zone; |
| 2248 | struct zoneref *z; |
| 2249 | |
| 2250 | /* |
| 2251 | * Make sure at least one zone would pass __compaction_suitable if we continue |
| 2252 | * retrying the reclaim. |
| 2253 | */ |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2254 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, |
| 2255 | ac->highest_zoneidx, ac->nodemask) { |
Michal Hocko | 86a294a | 2016-05-20 16:57:12 -0700 | [diff] [blame] | 2256 | unsigned long available; |
| 2257 | enum compact_result compact_result; |
| 2258 | |
| 2259 | /* |
| 2260 | * Do not consider all the reclaimable memory because we do not |
| 2261 | * want to trash just for a single high order allocation which |
| 2262 | * is even not guaranteed to appear even if __compaction_suitable |
| 2263 | * is happy about the watermark check. |
| 2264 | */ |
Mel Gorman | 5a1c84b | 2016-07-28 15:47:31 -0700 | [diff] [blame] | 2265 | available = zone_reclaimable_pages(zone) / order; |
Michal Hocko | 86a294a | 2016-05-20 16:57:12 -0700 | [diff] [blame] | 2266 | available += zone_page_state_snapshot(zone, NR_FREE_PAGES); |
| 2267 | compact_result = __compaction_suitable(zone, order, alloc_flags, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2268 | ac->highest_zoneidx, available); |
Vlastimil Babka | cc5c9f0 | 2016-10-07 17:00:43 -0700 | [diff] [blame] | 2269 | if (compact_result != COMPACT_SKIPPED) |
Michal Hocko | 86a294a | 2016-05-20 16:57:12 -0700 | [diff] [blame] | 2270 | return true; |
| 2271 | } |
| 2272 | |
| 2273 | return false; |
| 2274 | } |
| 2275 | |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2276 | static enum compact_result |
| 2277 | compact_zone(struct compact_control *cc, struct capture_control *capc) |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2278 | { |
Michal Hocko | ea7ab98 | 2016-05-20 16:56:38 -0700 | [diff] [blame] | 2279 | enum compact_result ret; |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2280 | unsigned long start_pfn = cc->zone->zone_start_pfn; |
| 2281 | unsigned long end_pfn = zone_end_pfn(cc->zone); |
Mel Gorman | 566e54e | 2019-03-05 15:44:32 -0800 | [diff] [blame] | 2282 | unsigned long last_migrated_pfn; |
David Rientjes | e0b9dae | 2014-06-04 16:08:28 -0700 | [diff] [blame] | 2283 | const bool sync = cc->mode != MIGRATE_ASYNC; |
Mel Gorman | 8854c55 | 2019-03-05 15:45:18 -0800 | [diff] [blame] | 2284 | bool update_cached; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2285 | |
Yafang Shao | a94b525 | 2019-09-23 15:36:54 -0700 | [diff] [blame] | 2286 | /* |
| 2287 | * These counters track activities during zone compaction. Initialize |
| 2288 | * them before compacting a new zone. |
| 2289 | */ |
| 2290 | cc->total_migrate_scanned = 0; |
| 2291 | cc->total_free_scanned = 0; |
| 2292 | cc->nr_migratepages = 0; |
| 2293 | cc->nr_freepages = 0; |
| 2294 | INIT_LIST_HEAD(&cc->freepages); |
| 2295 | INIT_LIST_HEAD(&cc->migratepages); |
| 2296 | |
Wei Yang | 01c0bfe | 2020-06-03 15:59:08 -0700 | [diff] [blame] | 2297 | cc->migratetype = gfp_migratetype(cc->gfp_mask); |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2298 | ret = compaction_suitable(cc->zone, cc->order, cc->alloc_flags, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2299 | cc->highest_zoneidx); |
Michal Hocko | c46649d | 2016-05-20 16:56:41 -0700 | [diff] [blame] | 2300 | /* Compaction is likely to fail */ |
Vlastimil Babka | cf37831 | 2016-10-07 16:57:41 -0700 | [diff] [blame] | 2301 | if (ret == COMPACT_SUCCESS || ret == COMPACT_SKIPPED) |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2302 | return ret; |
Michal Hocko | c46649d | 2016-05-20 16:56:41 -0700 | [diff] [blame] | 2303 | |
| 2304 | /* huh, compaction_suitable is returning something unexpected */ |
| 2305 | VM_BUG_ON(ret != COMPACT_CONTINUE); |
Mel Gorman | 3e7d344 | 2011-01-13 15:45:56 -0800 | [diff] [blame] | 2306 | |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 2307 | /* |
Vlastimil Babka | d3132e4 | 2014-01-21 15:51:08 -0800 | [diff] [blame] | 2308 | * Clear pageblock skip if there were failures recently and compaction |
Vlastimil Babka | accf624 | 2016-03-17 14:18:15 -0700 | [diff] [blame] | 2309 | * is about to be retried after being deferred. |
Vlastimil Babka | d3132e4 | 2014-01-21 15:51:08 -0800 | [diff] [blame] | 2310 | */ |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2311 | if (compaction_restarting(cc->zone, cc->order)) |
| 2312 | __reset_isolation_suitable(cc->zone); |
Vlastimil Babka | d3132e4 | 2014-01-21 15:51:08 -0800 | [diff] [blame] | 2313 | |
| 2314 | /* |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 2315 | * Setup to move all movable pages to the end of the zone. Used cached |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2316 | * information on where the scanners should start (unless we explicitly |
| 2317 | * want to compact the whole zone), but check that it is initialised |
| 2318 | * by ensuring the values are within zone boundaries. |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 2319 | */ |
Mel Gorman | 70b4459 | 2019-03-05 15:44:54 -0800 | [diff] [blame] | 2320 | cc->fast_start_pfn = 0; |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2321 | if (cc->whole_zone) { |
Mel Gorman | c89511a | 2012-10-08 16:32:45 -0700 | [diff] [blame] | 2322 | cc->migrate_pfn = start_pfn; |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2323 | cc->free_pfn = pageblock_start_pfn(end_pfn - 1); |
| 2324 | } else { |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2325 | cc->migrate_pfn = cc->zone->compact_cached_migrate_pfn[sync]; |
| 2326 | cc->free_pfn = cc->zone->compact_cached_free_pfn; |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2327 | if (cc->free_pfn < start_pfn || cc->free_pfn >= end_pfn) { |
| 2328 | cc->free_pfn = pageblock_start_pfn(end_pfn - 1); |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2329 | cc->zone->compact_cached_free_pfn = cc->free_pfn; |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2330 | } |
| 2331 | if (cc->migrate_pfn < start_pfn || cc->migrate_pfn >= end_pfn) { |
| 2332 | cc->migrate_pfn = start_pfn; |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2333 | cc->zone->compact_cached_migrate_pfn[0] = cc->migrate_pfn; |
| 2334 | cc->zone->compact_cached_migrate_pfn[1] = cc->migrate_pfn; |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2335 | } |
Michal Hocko | c8f7de0 | 2016-05-20 16:56:47 -0700 | [diff] [blame] | 2336 | |
Mel Gorman | e332f74 | 2019-03-05 15:45:38 -0800 | [diff] [blame] | 2337 | if (cc->migrate_pfn <= cc->zone->compact_init_migrate_pfn) |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2338 | cc->whole_zone = true; |
| 2339 | } |
Michal Hocko | c8f7de0 | 2016-05-20 16:56:47 -0700 | [diff] [blame] | 2340 | |
Mel Gorman | 566e54e | 2019-03-05 15:44:32 -0800 | [diff] [blame] | 2341 | last_migrated_pfn = 0; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2342 | |
Mel Gorman | 8854c55 | 2019-03-05 15:45:18 -0800 | [diff] [blame] | 2343 | /* |
| 2344 | * Migrate has separate cached PFNs for ASYNC and SYNC* migration on |
| 2345 | * the basis that some migrations will fail in ASYNC mode. However, |
| 2346 | * if the cached PFNs match and pageblocks are skipped due to having |
| 2347 | * no isolation candidates, then the sync state does not matter. |
| 2348 | * Until a pageblock with isolation candidates is found, keep the |
| 2349 | * cached PFNs in sync to avoid revisiting the same blocks. |
| 2350 | */ |
| 2351 | update_cached = !sync && |
| 2352 | cc->zone->compact_cached_migrate_pfn[0] == cc->zone->compact_cached_migrate_pfn[1]; |
| 2353 | |
Joonsoo Kim | 16c4a09 | 2015-02-11 15:27:01 -0800 | [diff] [blame] | 2354 | trace_mm_compaction_begin(start_pfn, cc->migrate_pfn, |
| 2355 | cc->free_pfn, end_pfn, sync); |
Mel Gorman | 0eb927c | 2014-01-21 15:51:05 -0800 | [diff] [blame] | 2356 | |
Minchan Kim | 361a2a2 | 2021-05-04 18:36:57 -0700 | [diff] [blame] | 2357 | /* lru_add_drain_all could be expensive with involving other CPUs */ |
| 2358 | lru_add_drain(); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2359 | |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2360 | while ((ret = compact_finished(cc)) == COMPACT_CONTINUE) { |
Minchan Kim | 9d502c1 | 2011-03-22 16:30:39 -0700 | [diff] [blame] | 2361 | int err; |
Yanfei Xu | 19d3cf9 | 2020-12-14 19:12:39 -0800 | [diff] [blame] | 2362 | unsigned long iteration_start_pfn = cc->migrate_pfn; |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2363 | |
Mel Gorman | 804d312 | 2019-03-05 15:45:07 -0800 | [diff] [blame] | 2364 | /* |
| 2365 | * Avoid multiple rescans which can happen if a page cannot be |
| 2366 | * isolated (dirty/writeback in async mode) or if the migrated |
| 2367 | * pages are being allocated before the pageblock is cleared. |
| 2368 | * The first rescan will capture the entire pageblock for |
| 2369 | * migration. If it fails, it'll be marked skip and scanning |
| 2370 | * will proceed as normal. |
| 2371 | */ |
| 2372 | cc->rescan = false; |
| 2373 | if (pageblock_start_pfn(last_migrated_pfn) == |
Yanfei Xu | 19d3cf9 | 2020-12-14 19:12:39 -0800 | [diff] [blame] | 2374 | pageblock_start_pfn(iteration_start_pfn)) { |
Mel Gorman | 804d312 | 2019-03-05 15:45:07 -0800 | [diff] [blame] | 2375 | cc->rescan = true; |
| 2376 | } |
| 2377 | |
Pengfei Li | 32aaf05 | 2019-09-23 15:36:58 -0700 | [diff] [blame] | 2378 | switch (isolate_migratepages(cc)) { |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 2379 | case ISOLATE_ABORT: |
Vlastimil Babka | 2d1e104 | 2015-11-05 18:48:02 -0800 | [diff] [blame] | 2380 | ret = COMPACT_CONTENDED; |
Rafael Aquini | 5733c7d | 2012-12-11 16:02:47 -0800 | [diff] [blame] | 2381 | putback_movable_pages(&cc->migratepages); |
Shaohua Li | e64c523 | 2012-10-08 16:32:27 -0700 | [diff] [blame] | 2382 | cc->nr_migratepages = 0; |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 2383 | goto out; |
| 2384 | case ISOLATE_NONE: |
Mel Gorman | 8854c55 | 2019-03-05 15:45:18 -0800 | [diff] [blame] | 2385 | if (update_cached) { |
| 2386 | cc->zone->compact_cached_migrate_pfn[1] = |
| 2387 | cc->zone->compact_cached_migrate_pfn[0]; |
| 2388 | } |
| 2389 | |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2390 | /* |
| 2391 | * We haven't isolated and migrated anything, but |
| 2392 | * there might still be unflushed migrations from |
| 2393 | * previous cc->order aligned block. |
| 2394 | */ |
| 2395 | goto check_drain; |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 2396 | case ISOLATE_SUCCESS: |
Mel Gorman | 8854c55 | 2019-03-05 15:45:18 -0800 | [diff] [blame] | 2397 | update_cached = false; |
Yanfei Xu | 19d3cf9 | 2020-12-14 19:12:39 -0800 | [diff] [blame] | 2398 | last_migrated_pfn = iteration_start_pfn; |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 2399 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2400 | |
David Rientjes | d53aea3 | 2014-06-04 16:08:26 -0700 | [diff] [blame] | 2401 | err = migrate_pages(&cc->migratepages, compaction_alloc, |
David Rientjes | e0b9dae | 2014-06-04 16:08:28 -0700 | [diff] [blame] | 2402 | compaction_free, (unsigned long)cc, cc->mode, |
Mel Gorman | 7b2a2d4 | 2012-10-19 14:07:31 +0100 | [diff] [blame] | 2403 | MR_COMPACTION); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2404 | |
Vlastimil Babka | f8c9301 | 2014-06-04 16:08:32 -0700 | [diff] [blame] | 2405 | trace_mm_compaction_migratepages(cc->nr_migratepages, err, |
| 2406 | &cc->migratepages); |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2407 | |
Vlastimil Babka | f8c9301 | 2014-06-04 16:08:32 -0700 | [diff] [blame] | 2408 | /* All pages were either migrated or will be released */ |
| 2409 | cc->nr_migratepages = 0; |
Minchan Kim | 9d502c1 | 2011-03-22 16:30:39 -0700 | [diff] [blame] | 2410 | if (err) { |
Rafael Aquini | 5733c7d | 2012-12-11 16:02:47 -0800 | [diff] [blame] | 2411 | putback_movable_pages(&cc->migratepages); |
Vlastimil Babka | 7ed695e | 2014-01-21 15:51:09 -0800 | [diff] [blame] | 2412 | /* |
| 2413 | * migrate_pages() may return -ENOMEM when scanners meet |
| 2414 | * and we want compact_finished() to detect it |
| 2415 | */ |
Vlastimil Babka | f2849aa | 2015-09-08 15:02:36 -0700 | [diff] [blame] | 2416 | if (err == -ENOMEM && !compact_scanners_met(cc)) { |
Vlastimil Babka | 2d1e104 | 2015-11-05 18:48:02 -0800 | [diff] [blame] | 2417 | ret = COMPACT_CONTENDED; |
David Rientjes | 4bf2bba | 2012-07-11 14:02:13 -0700 | [diff] [blame] | 2418 | goto out; |
| 2419 | } |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 2420 | /* |
| 2421 | * We failed to migrate at least one page in the current |
| 2422 | * order-aligned block, so skip the rest of it. |
| 2423 | */ |
| 2424 | if (cc->direct_compaction && |
| 2425 | (cc->mode == MIGRATE_ASYNC)) { |
| 2426 | cc->migrate_pfn = block_end_pfn( |
| 2427 | cc->migrate_pfn - 1, cc->order); |
| 2428 | /* Draining pcplists is useless in this case */ |
Mel Gorman | 566e54e | 2019-03-05 15:44:32 -0800 | [diff] [blame] | 2429 | last_migrated_pfn = 0; |
Vlastimil Babka | fdd048e | 2016-05-19 17:11:55 -0700 | [diff] [blame] | 2430 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2431 | } |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2432 | |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2433 | check_drain: |
| 2434 | /* |
| 2435 | * Has the migration scanner moved away from the previous |
| 2436 | * cc->order aligned block where we migrated from? If yes, |
| 2437 | * flush the pages that were freed, so that they can merge and |
| 2438 | * compact_finished() can detect immediately if allocation |
| 2439 | * would succeed. |
| 2440 | */ |
Mel Gorman | 566e54e | 2019-03-05 15:44:32 -0800 | [diff] [blame] | 2441 | if (cc->order > 0 && last_migrated_pfn) { |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2442 | unsigned long current_block_start = |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 2443 | block_start_pfn(cc->migrate_pfn, cc->order); |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2444 | |
Mel Gorman | 566e54e | 2019-03-05 15:44:32 -0800 | [diff] [blame] | 2445 | if (last_migrated_pfn < current_block_start) { |
Ingo Molnar | b01b214 | 2020-05-27 22:11:15 +0200 | [diff] [blame] | 2446 | lru_add_drain_cpu_zone(cc->zone); |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2447 | /* No more flushing until we migrate again */ |
Mel Gorman | 566e54e | 2019-03-05 15:44:32 -0800 | [diff] [blame] | 2448 | last_migrated_pfn = 0; |
Vlastimil Babka | fdaf7f5 | 2014-12-10 15:43:34 -0800 | [diff] [blame] | 2449 | } |
| 2450 | } |
| 2451 | |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2452 | /* Stop if a page has been captured */ |
| 2453 | if (capc && capc->page) { |
| 2454 | ret = COMPACT_SUCCESS; |
| 2455 | break; |
| 2456 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2457 | } |
| 2458 | |
Mel Gorman | f9e35b3 | 2011-06-15 15:08:52 -0700 | [diff] [blame] | 2459 | out: |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 2460 | /* |
| 2461 | * Release free pages and update where the free scanner should restart, |
| 2462 | * so we don't leave any returned pages behind in the next attempt. |
| 2463 | */ |
| 2464 | if (cc->nr_freepages > 0) { |
| 2465 | unsigned long free_pfn = release_freepages(&cc->freepages); |
| 2466 | |
| 2467 | cc->nr_freepages = 0; |
| 2468 | VM_BUG_ON(free_pfn == 0); |
| 2469 | /* The cached pfn is always the first in a pageblock */ |
Vlastimil Babka | 06b6640 | 2016-05-19 17:11:48 -0700 | [diff] [blame] | 2470 | free_pfn = pageblock_start_pfn(free_pfn); |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 2471 | /* |
| 2472 | * Only go back, not forward. The cached pfn might have been |
| 2473 | * already reset to zone end in compact_finished() |
| 2474 | */ |
Mel Gorman | 40cacbc | 2019-03-05 15:44:36 -0800 | [diff] [blame] | 2475 | if (free_pfn > cc->zone->compact_cached_free_pfn) |
| 2476 | cc->zone->compact_cached_free_pfn = free_pfn; |
Vlastimil Babka | 6bace09 | 2014-12-10 15:43:31 -0800 | [diff] [blame] | 2477 | } |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2478 | |
David Rientjes | 7f354a5 | 2017-02-22 15:44:50 -0800 | [diff] [blame] | 2479 | count_compact_events(COMPACTMIGRATE_SCANNED, cc->total_migrate_scanned); |
| 2480 | count_compact_events(COMPACTFREE_SCANNED, cc->total_free_scanned); |
| 2481 | |
Joonsoo Kim | 16c4a09 | 2015-02-11 15:27:01 -0800 | [diff] [blame] | 2482 | trace_mm_compaction_end(start_pfn, cc->migrate_pfn, |
| 2483 | cc->free_pfn, end_pfn, sync, ret); |
Mel Gorman | 0eb927c | 2014-01-21 15:51:05 -0800 | [diff] [blame] | 2484 | |
Mel Gorman | 748446b | 2010-05-24 14:32:27 -0700 | [diff] [blame] | 2485 | return ret; |
| 2486 | } |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2487 | |
Michal Hocko | ea7ab98 | 2016-05-20 16:56:38 -0700 | [diff] [blame] | 2488 | static enum compact_result compact_zone_order(struct zone *zone, int order, |
Vlastimil Babka | c3486f5 | 2016-07-28 15:49:30 -0700 | [diff] [blame] | 2489 | gfp_t gfp_mask, enum compact_priority prio, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2490 | unsigned int alloc_flags, int highest_zoneidx, |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2491 | struct page **capture) |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2492 | { |
Michal Hocko | ea7ab98 | 2016-05-20 16:56:38 -0700 | [diff] [blame] | 2493 | enum compact_result ret; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2494 | struct compact_control cc = { |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2495 | .order = order, |
Mel Gorman | dbe2d4e | 2019-03-05 15:45:31 -0800 | [diff] [blame] | 2496 | .search_order = order, |
David Rientjes | 6d7ce55 | 2014-10-09 15:27:27 -0700 | [diff] [blame] | 2497 | .gfp_mask = gfp_mask, |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2498 | .zone = zone, |
Vlastimil Babka | a5508cd | 2016-07-28 15:49:28 -0700 | [diff] [blame] | 2499 | .mode = (prio == COMPACT_PRIO_ASYNC) ? |
| 2500 | MIGRATE_ASYNC : MIGRATE_SYNC_LIGHT, |
Vlastimil Babka | ebff398 | 2014-12-10 15:43:22 -0800 | [diff] [blame] | 2501 | .alloc_flags = alloc_flags, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2502 | .highest_zoneidx = highest_zoneidx, |
Vlastimil Babka | accf624 | 2016-03-17 14:18:15 -0700 | [diff] [blame] | 2503 | .direct_compaction = true, |
Vlastimil Babka | a8e025e | 2016-10-07 16:57:47 -0700 | [diff] [blame] | 2504 | .whole_zone = (prio == MIN_COMPACT_PRIORITY), |
Vlastimil Babka | 9f7e338 | 2016-10-07 17:00:37 -0700 | [diff] [blame] | 2505 | .ignore_skip_hint = (prio == MIN_COMPACT_PRIORITY), |
| 2506 | .ignore_block_suitable = (prio == MIN_COMPACT_PRIORITY) |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2507 | }; |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2508 | struct capture_control capc = { |
| 2509 | .cc = &cc, |
| 2510 | .page = NULL, |
| 2511 | }; |
| 2512 | |
Vlastimil Babka | b9e20f0 | 2020-06-25 20:29:24 -0700 | [diff] [blame] | 2513 | /* |
| 2514 | * Make sure the structs are really initialized before we expose the |
| 2515 | * capture control, in case we are interrupted and the interrupt handler |
| 2516 | * frees a page. |
| 2517 | */ |
| 2518 | barrier(); |
| 2519 | WRITE_ONCE(current->capture_control, &capc); |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2520 | |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2521 | ret = compact_zone(&cc, &capc); |
Shaohua Li | e64c523 | 2012-10-08 16:32:27 -0700 | [diff] [blame] | 2522 | |
| 2523 | VM_BUG_ON(!list_empty(&cc.freepages)); |
| 2524 | VM_BUG_ON(!list_empty(&cc.migratepages)); |
| 2525 | |
Vlastimil Babka | b9e20f0 | 2020-06-25 20:29:24 -0700 | [diff] [blame] | 2526 | /* |
| 2527 | * Make sure we hide capture control first before we read the captured |
| 2528 | * page pointer, otherwise an interrupt could free and capture a page |
| 2529 | * and we would leak it. |
| 2530 | */ |
| 2531 | WRITE_ONCE(current->capture_control, NULL); |
| 2532 | *capture = READ_ONCE(capc.page); |
Charan Teja Reddy | 06dac2f | 2021-05-04 18:36:51 -0700 | [diff] [blame] | 2533 | /* |
| 2534 | * Technically, it is also possible that compaction is skipped but |
| 2535 | * the page is still captured out of luck(IRQ came and freed the page). |
| 2536 | * Returning COMPACT_SUCCESS in such cases helps in properly accounting |
| 2537 | * the COMPACT[STALL|FAIL] when compaction is skipped. |
| 2538 | */ |
| 2539 | if (*capture) |
| 2540 | ret = COMPACT_SUCCESS; |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2541 | |
Shaohua Li | e64c523 | 2012-10-08 16:32:27 -0700 | [diff] [blame] | 2542 | return ret; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2543 | } |
| 2544 | |
Mel Gorman | 5e77190 | 2010-05-24 14:32:31 -0700 | [diff] [blame] | 2545 | int sysctl_extfrag_threshold = 500; |
| 2546 | |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2547 | /** |
| 2548 | * try_to_compact_pages - Direct compact to satisfy a high-order allocation |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2549 | * @gfp_mask: The GFP mask of the current allocation |
Vlastimil Babka | 1a6d53a | 2015-02-11 15:25:44 -0800 | [diff] [blame] | 2550 | * @order: The order of the current allocation |
| 2551 | * @alloc_flags: The allocation flags of the current allocation |
| 2552 | * @ac: The context of current allocation |
Yang Shi | 112d2d2 | 2018-01-31 16:20:23 -0800 | [diff] [blame] | 2553 | * @prio: Determines how hard direct compaction should try to succeed |
Vlastimil Babka | 6467552 | 2020-04-01 21:10:35 -0700 | [diff] [blame] | 2554 | * @capture: Pointer to free page created by compaction will be stored here |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2555 | * |
| 2556 | * This is the main entry point for direct page compaction. |
| 2557 | */ |
Michal Hocko | ea7ab98 | 2016-05-20 16:56:38 -0700 | [diff] [blame] | 2558 | enum compact_result try_to_compact_pages(gfp_t gfp_mask, unsigned int order, |
Mel Gorman | c603844 | 2016-05-19 17:13:38 -0700 | [diff] [blame] | 2559 | unsigned int alloc_flags, const struct alloc_context *ac, |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2560 | enum compact_priority prio, struct page **capture) |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2561 | { |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2562 | int may_perform_io = gfp_mask & __GFP_IO; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2563 | struct zoneref *z; |
| 2564 | struct zone *zone; |
Michal Hocko | 1d4746d | 2016-05-20 16:56:44 -0700 | [diff] [blame] | 2565 | enum compact_result rc = COMPACT_SKIPPED; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2566 | |
Michal Hocko | 73e64c51 | 2016-12-14 15:04:07 -0800 | [diff] [blame] | 2567 | /* |
| 2568 | * Check if the GFP flags allow compaction - GFP_NOIO is really |
| 2569 | * tricky context because the migration might require IO |
| 2570 | */ |
| 2571 | if (!may_perform_io) |
Vlastimil Babka | 53853e2 | 2014-10-09 15:27:02 -0700 | [diff] [blame] | 2572 | return COMPACT_SKIPPED; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2573 | |
Vlastimil Babka | a5508cd | 2016-07-28 15:49:28 -0700 | [diff] [blame] | 2574 | trace_mm_compaction_try_to_compact_pages(order, gfp_mask, prio); |
Joonsoo Kim | 837d026 | 2015-02-11 15:27:06 -0800 | [diff] [blame] | 2575 | |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2576 | /* Compact each zone in the list */ |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2577 | for_each_zone_zonelist_nodemask(zone, z, ac->zonelist, |
| 2578 | ac->highest_zoneidx, ac->nodemask) { |
Michal Hocko | ea7ab98 | 2016-05-20 16:56:38 -0700 | [diff] [blame] | 2579 | enum compact_result status; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2580 | |
Vlastimil Babka | a8e025e | 2016-10-07 16:57:47 -0700 | [diff] [blame] | 2581 | if (prio > MIN_COMPACT_PRIORITY |
| 2582 | && compaction_deferred(zone, order)) { |
Michal Hocko | 1d4746d | 2016-05-20 16:56:44 -0700 | [diff] [blame] | 2583 | rc = max_t(enum compact_result, COMPACT_DEFERRED, rc); |
Vlastimil Babka | 53853e2 | 2014-10-09 15:27:02 -0700 | [diff] [blame] | 2584 | continue; |
Michal Hocko | 1d4746d | 2016-05-20 16:56:44 -0700 | [diff] [blame] | 2585 | } |
Vlastimil Babka | 53853e2 | 2014-10-09 15:27:02 -0700 | [diff] [blame] | 2586 | |
Vlastimil Babka | a5508cd | 2016-07-28 15:49:28 -0700 | [diff] [blame] | 2587 | status = compact_zone_order(zone, order, gfp_mask, prio, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2588 | alloc_flags, ac->highest_zoneidx, capture); |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2589 | rc = max(status, rc); |
| 2590 | |
Vlastimil Babka | 7ceb009 | 2016-10-07 16:57:44 -0700 | [diff] [blame] | 2591 | /* The allocation should succeed, stop compacting */ |
| 2592 | if (status == COMPACT_SUCCESS) { |
Vlastimil Babka | 53853e2 | 2014-10-09 15:27:02 -0700 | [diff] [blame] | 2593 | /* |
| 2594 | * We think the allocation will succeed in this zone, |
| 2595 | * but it is not certain, hence the false. The caller |
| 2596 | * will repeat this with true if allocation indeed |
| 2597 | * succeeds in this zone. |
| 2598 | */ |
| 2599 | compaction_defer_reset(zone, order, false); |
Vlastimil Babka | 1f9efde | 2014-10-09 15:27:14 -0700 | [diff] [blame] | 2600 | |
Vlastimil Babka | c3486f5 | 2016-07-28 15:49:30 -0700 | [diff] [blame] | 2601 | break; |
Vlastimil Babka | 1f9efde | 2014-10-09 15:27:14 -0700 | [diff] [blame] | 2602 | } |
| 2603 | |
Vlastimil Babka | a5508cd | 2016-07-28 15:49:28 -0700 | [diff] [blame] | 2604 | if (prio != COMPACT_PRIO_ASYNC && (status == COMPACT_COMPLETE || |
Vlastimil Babka | c3486f5 | 2016-07-28 15:49:30 -0700 | [diff] [blame] | 2605 | status == COMPACT_PARTIAL_SKIPPED)) |
Vlastimil Babka | 53853e2 | 2014-10-09 15:27:02 -0700 | [diff] [blame] | 2606 | /* |
| 2607 | * We think that allocation won't succeed in this zone |
| 2608 | * so we defer compaction there. If it ends up |
| 2609 | * succeeding after all, it will be reset. |
| 2610 | */ |
| 2611 | defer_compaction(zone, order); |
Vlastimil Babka | 1f9efde | 2014-10-09 15:27:14 -0700 | [diff] [blame] | 2612 | |
| 2613 | /* |
| 2614 | * We might have stopped compacting due to need_resched() in |
| 2615 | * async compaction, or due to a fatal signal detected. In that |
Vlastimil Babka | c3486f5 | 2016-07-28 15:49:30 -0700 | [diff] [blame] | 2616 | * case do not try further zones |
Vlastimil Babka | 1f9efde | 2014-10-09 15:27:14 -0700 | [diff] [blame] | 2617 | */ |
Vlastimil Babka | c3486f5 | 2016-07-28 15:49:30 -0700 | [diff] [blame] | 2618 | if ((prio == COMPACT_PRIO_ASYNC && need_resched()) |
| 2619 | || fatal_signal_pending(current)) |
| 2620 | break; |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2621 | } |
| 2622 | |
| 2623 | return rc; |
| 2624 | } |
| 2625 | |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2626 | /* |
| 2627 | * Compact all zones within a node till each zone's fragmentation score |
| 2628 | * reaches within proactive compaction thresholds (as determined by the |
| 2629 | * proactiveness tunable). |
| 2630 | * |
| 2631 | * It is possible that the function returns before reaching score targets |
| 2632 | * due to various back-off conditions, such as, contention on per-node or |
| 2633 | * per-zone locks. |
| 2634 | */ |
| 2635 | static void proactive_compact_node(pg_data_t *pgdat) |
| 2636 | { |
| 2637 | int zoneid; |
| 2638 | struct zone *zone; |
| 2639 | struct compact_control cc = { |
| 2640 | .order = -1, |
| 2641 | .mode = MIGRATE_SYNC_LIGHT, |
| 2642 | .ignore_skip_hint = true, |
| 2643 | .whole_zone = true, |
| 2644 | .gfp_mask = GFP_KERNEL, |
| 2645 | .proactive_compaction = true, |
| 2646 | }; |
| 2647 | |
| 2648 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { |
| 2649 | zone = &pgdat->node_zones[zoneid]; |
| 2650 | if (!populated_zone(zone)) |
| 2651 | continue; |
| 2652 | |
| 2653 | cc.zone = zone; |
| 2654 | |
| 2655 | compact_zone(&cc, NULL); |
| 2656 | |
| 2657 | VM_BUG_ON(!list_empty(&cc.freepages)); |
| 2658 | VM_BUG_ON(!list_empty(&cc.migratepages)); |
| 2659 | } |
| 2660 | } |
Mel Gorman | 56de726 | 2010-05-24 14:32:30 -0700 | [diff] [blame] | 2661 | |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2662 | /* Compact all zones within a node */ |
Andrew Morton | 7103f16 | 2013-02-22 16:32:33 -0800 | [diff] [blame] | 2663 | static void compact_node(int nid) |
Rik van Riel | 7be62de | 2012-03-21 16:33:52 -0700 | [diff] [blame] | 2664 | { |
Vlastimil Babka | 791cae9 | 2016-10-07 16:57:38 -0700 | [diff] [blame] | 2665 | pg_data_t *pgdat = NODE_DATA(nid); |
| 2666 | int zoneid; |
| 2667 | struct zone *zone; |
Rik van Riel | 7be62de | 2012-03-21 16:33:52 -0700 | [diff] [blame] | 2668 | struct compact_control cc = { |
| 2669 | .order = -1, |
David Rientjes | e0b9dae | 2014-06-04 16:08:28 -0700 | [diff] [blame] | 2670 | .mode = MIGRATE_SYNC, |
David Rientjes | 91ca918 | 2014-04-03 14:47:23 -0700 | [diff] [blame] | 2671 | .ignore_skip_hint = true, |
Vlastimil Babka | 06ed299 | 2016-10-07 16:57:35 -0700 | [diff] [blame] | 2672 | .whole_zone = true, |
Michal Hocko | 73e64c51 | 2016-12-14 15:04:07 -0800 | [diff] [blame] | 2673 | .gfp_mask = GFP_KERNEL, |
Rik van Riel | 7be62de | 2012-03-21 16:33:52 -0700 | [diff] [blame] | 2674 | }; |
| 2675 | |
Vlastimil Babka | 791cae9 | 2016-10-07 16:57:38 -0700 | [diff] [blame] | 2676 | |
| 2677 | for (zoneid = 0; zoneid < MAX_NR_ZONES; zoneid++) { |
| 2678 | |
| 2679 | zone = &pgdat->node_zones[zoneid]; |
| 2680 | if (!populated_zone(zone)) |
| 2681 | continue; |
| 2682 | |
Vlastimil Babka | 791cae9 | 2016-10-07 16:57:38 -0700 | [diff] [blame] | 2683 | cc.zone = zone; |
Vlastimil Babka | 791cae9 | 2016-10-07 16:57:38 -0700 | [diff] [blame] | 2684 | |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2685 | compact_zone(&cc, NULL); |
Vlastimil Babka | 791cae9 | 2016-10-07 16:57:38 -0700 | [diff] [blame] | 2686 | |
| 2687 | VM_BUG_ON(!list_empty(&cc.freepages)); |
| 2688 | VM_BUG_ON(!list_empty(&cc.migratepages)); |
| 2689 | } |
Rik van Riel | 7be62de | 2012-03-21 16:33:52 -0700 | [diff] [blame] | 2690 | } |
| 2691 | |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2692 | /* Compact all nodes in the system */ |
Jason Liu | 7964c06 | 2013-01-11 14:31:47 -0800 | [diff] [blame] | 2693 | static void compact_nodes(void) |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2694 | { |
| 2695 | int nid; |
| 2696 | |
Hugh Dickins | 8575ec2 | 2012-03-21 16:33:53 -0700 | [diff] [blame] | 2697 | /* Flush pending updates to the LRU lists */ |
| 2698 | lru_add_drain_all(); |
| 2699 | |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2700 | for_each_online_node(nid) |
| 2701 | compact_node(nid); |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2702 | } |
| 2703 | |
Yaowei Bai | fec4eb2 | 2016-01-14 15:20:09 -0800 | [diff] [blame] | 2704 | /* |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2705 | * Tunable for proactive compaction. It determines how |
| 2706 | * aggressively the kernel should compact memory in the |
| 2707 | * background. It takes values in the range [0, 100]. |
| 2708 | */ |
Nitin Gupta | d34c0a7 | 2020-08-11 18:31:07 -0700 | [diff] [blame] | 2709 | unsigned int __read_mostly sysctl_compaction_proactiveness = 20; |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2710 | |
| 2711 | /* |
Yaowei Bai | fec4eb2 | 2016-01-14 15:20:09 -0800 | [diff] [blame] | 2712 | * This is the entry point for compacting all nodes via |
| 2713 | * /proc/sys/vm/compact_memory |
| 2714 | */ |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2715 | int sysctl_compaction_handler(struct ctl_table *table, int write, |
Christoph Hellwig | 3292739 | 2020-04-24 08:43:38 +0200 | [diff] [blame] | 2716 | void *buffer, size_t *length, loff_t *ppos) |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2717 | { |
| 2718 | if (write) |
Jason Liu | 7964c06 | 2013-01-11 14:31:47 -0800 | [diff] [blame] | 2719 | compact_nodes(); |
Mel Gorman | 76ab0f5 | 2010-05-24 14:32:28 -0700 | [diff] [blame] | 2720 | |
| 2721 | return 0; |
| 2722 | } |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 2723 | |
| 2724 | #if defined(CONFIG_SYSFS) && defined(CONFIG_NUMA) |
Rashika Kheria | 74e77fb | 2014-04-03 14:48:01 -0700 | [diff] [blame] | 2725 | static ssize_t sysfs_compact_node(struct device *dev, |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 2726 | struct device_attribute *attr, |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 2727 | const char *buf, size_t count) |
| 2728 | { |
Hugh Dickins | 8575ec2 | 2012-03-21 16:33:53 -0700 | [diff] [blame] | 2729 | int nid = dev->id; |
| 2730 | |
| 2731 | if (nid >= 0 && nid < nr_node_ids && node_online(nid)) { |
| 2732 | /* Flush pending updates to the LRU lists */ |
| 2733 | lru_add_drain_all(); |
| 2734 | |
| 2735 | compact_node(nid); |
| 2736 | } |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 2737 | |
| 2738 | return count; |
| 2739 | } |
Joe Perches | 0825a6f | 2018-06-14 15:27:58 -0700 | [diff] [blame] | 2740 | static DEVICE_ATTR(compact, 0200, NULL, sysfs_compact_node); |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 2741 | |
| 2742 | int compaction_register_node(struct node *node) |
| 2743 | { |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 2744 | return device_create_file(&node->dev, &dev_attr_compact); |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 2745 | } |
| 2746 | |
| 2747 | void compaction_unregister_node(struct node *node) |
| 2748 | { |
Kay Sievers | 10fbcf4 | 2011-12-21 14:48:43 -0800 | [diff] [blame] | 2749 | return device_remove_file(&node->dev, &dev_attr_compact); |
Mel Gorman | ed4a6d7 | 2010-05-24 14:32:29 -0700 | [diff] [blame] | 2750 | } |
| 2751 | #endif /* CONFIG_SYSFS && CONFIG_NUMA */ |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 2752 | |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2753 | static inline bool kcompactd_work_requested(pg_data_t *pgdat) |
| 2754 | { |
Vlastimil Babka | 172400c | 2016-05-05 16:22:32 -0700 | [diff] [blame] | 2755 | return pgdat->kcompactd_max_order > 0 || kthread_should_stop(); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2756 | } |
| 2757 | |
| 2758 | static bool kcompactd_node_suitable(pg_data_t *pgdat) |
| 2759 | { |
| 2760 | int zoneid; |
| 2761 | struct zone *zone; |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2762 | enum zone_type highest_zoneidx = pgdat->kcompactd_highest_zoneidx; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2763 | |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2764 | for (zoneid = 0; zoneid <= highest_zoneidx; zoneid++) { |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2765 | zone = &pgdat->node_zones[zoneid]; |
| 2766 | |
| 2767 | if (!populated_zone(zone)) |
| 2768 | continue; |
| 2769 | |
| 2770 | if (compaction_suitable(zone, pgdat->kcompactd_max_order, 0, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2771 | highest_zoneidx) == COMPACT_CONTINUE) |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2772 | return true; |
| 2773 | } |
| 2774 | |
| 2775 | return false; |
| 2776 | } |
| 2777 | |
| 2778 | static void kcompactd_do_work(pg_data_t *pgdat) |
| 2779 | { |
| 2780 | /* |
| 2781 | * With no special task, compact all zones so that a page of requested |
| 2782 | * order is allocatable. |
| 2783 | */ |
| 2784 | int zoneid; |
| 2785 | struct zone *zone; |
| 2786 | struct compact_control cc = { |
| 2787 | .order = pgdat->kcompactd_max_order, |
Mel Gorman | dbe2d4e | 2019-03-05 15:45:31 -0800 | [diff] [blame] | 2788 | .search_order = pgdat->kcompactd_max_order, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2789 | .highest_zoneidx = pgdat->kcompactd_highest_zoneidx, |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2790 | .mode = MIGRATE_SYNC_LIGHT, |
David Rientjes | a0647dc | 2017-11-17 15:26:27 -0800 | [diff] [blame] | 2791 | .ignore_skip_hint = false, |
Michal Hocko | 73e64c51 | 2016-12-14 15:04:07 -0800 | [diff] [blame] | 2792 | .gfp_mask = GFP_KERNEL, |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2793 | }; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2794 | trace_mm_compaction_kcompactd_wake(pgdat->node_id, cc.order, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2795 | cc.highest_zoneidx); |
David Rientjes | 7f354a5 | 2017-02-22 15:44:50 -0800 | [diff] [blame] | 2796 | count_compact_event(KCOMPACTD_WAKE); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2797 | |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2798 | for (zoneid = 0; zoneid <= cc.highest_zoneidx; zoneid++) { |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2799 | int status; |
| 2800 | |
| 2801 | zone = &pgdat->node_zones[zoneid]; |
| 2802 | if (!populated_zone(zone)) |
| 2803 | continue; |
| 2804 | |
| 2805 | if (compaction_deferred(zone, cc.order)) |
| 2806 | continue; |
| 2807 | |
| 2808 | if (compaction_suitable(zone, cc.order, 0, zoneid) != |
| 2809 | COMPACT_CONTINUE) |
| 2810 | continue; |
| 2811 | |
Vlastimil Babka | 172400c | 2016-05-05 16:22:32 -0700 | [diff] [blame] | 2812 | if (kthread_should_stop()) |
| 2813 | return; |
Yafang Shao | a94b525 | 2019-09-23 15:36:54 -0700 | [diff] [blame] | 2814 | |
| 2815 | cc.zone = zone; |
Mel Gorman | 5e1f0f0 | 2019-03-05 15:45:41 -0800 | [diff] [blame] | 2816 | status = compact_zone(&cc, NULL); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2817 | |
Vlastimil Babka | 7ceb009 | 2016-10-07 16:57:44 -0700 | [diff] [blame] | 2818 | if (status == COMPACT_SUCCESS) { |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2819 | compaction_defer_reset(zone, cc.order, false); |
Michal Hocko | c8f7de0 | 2016-05-20 16:56:47 -0700 | [diff] [blame] | 2820 | } else if (status == COMPACT_PARTIAL_SKIPPED || status == COMPACT_COMPLETE) { |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2821 | /* |
David Rientjes | bc3106b | 2018-04-05 16:24:02 -0700 | [diff] [blame] | 2822 | * Buddy pages may become stranded on pcps that could |
| 2823 | * otherwise coalesce on the zone's free area for |
| 2824 | * order >= cc.order. This is ratelimited by the |
| 2825 | * upcoming deferral. |
| 2826 | */ |
| 2827 | drain_all_pages(zone); |
| 2828 | |
| 2829 | /* |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2830 | * We use sync migration mode here, so we defer like |
| 2831 | * sync direct compaction does. |
| 2832 | */ |
| 2833 | defer_compaction(zone, cc.order); |
| 2834 | } |
| 2835 | |
David Rientjes | 7f354a5 | 2017-02-22 15:44:50 -0800 | [diff] [blame] | 2836 | count_compact_events(KCOMPACTD_MIGRATE_SCANNED, |
| 2837 | cc.total_migrate_scanned); |
| 2838 | count_compact_events(KCOMPACTD_FREE_SCANNED, |
| 2839 | cc.total_free_scanned); |
| 2840 | |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2841 | VM_BUG_ON(!list_empty(&cc.freepages)); |
| 2842 | VM_BUG_ON(!list_empty(&cc.migratepages)); |
| 2843 | } |
| 2844 | |
| 2845 | /* |
| 2846 | * Regardless of success, we are done until woken up next. But remember |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2847 | * the requested order/highest_zoneidx in case it was higher/tighter |
| 2848 | * than our current ones |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2849 | */ |
| 2850 | if (pgdat->kcompactd_max_order <= cc.order) |
| 2851 | pgdat->kcompactd_max_order = 0; |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2852 | if (pgdat->kcompactd_highest_zoneidx >= cc.highest_zoneidx) |
| 2853 | pgdat->kcompactd_highest_zoneidx = pgdat->nr_zones - 1; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2854 | } |
| 2855 | |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2856 | void wakeup_kcompactd(pg_data_t *pgdat, int order, int highest_zoneidx) |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2857 | { |
| 2858 | if (!order) |
| 2859 | return; |
| 2860 | |
| 2861 | if (pgdat->kcompactd_max_order < order) |
| 2862 | pgdat->kcompactd_max_order = order; |
| 2863 | |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2864 | if (pgdat->kcompactd_highest_zoneidx > highest_zoneidx) |
| 2865 | pgdat->kcompactd_highest_zoneidx = highest_zoneidx; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2866 | |
Davidlohr Bueso | 6818600 | 2017-10-03 16:15:03 -0700 | [diff] [blame] | 2867 | /* |
| 2868 | * Pairs with implicit barrier in wait_event_freezable() |
| 2869 | * such that wakeups are not missed. |
| 2870 | */ |
| 2871 | if (!wq_has_sleeper(&pgdat->kcompactd_wait)) |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2872 | return; |
| 2873 | |
| 2874 | if (!kcompactd_node_suitable(pgdat)) |
| 2875 | return; |
| 2876 | |
| 2877 | trace_mm_compaction_wakeup_kcompactd(pgdat->node_id, order, |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2878 | highest_zoneidx); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2879 | wake_up_interruptible(&pgdat->kcompactd_wait); |
| 2880 | } |
| 2881 | |
| 2882 | /* |
| 2883 | * The background compaction daemon, started as a kernel thread |
| 2884 | * from the init process. |
| 2885 | */ |
| 2886 | static int kcompactd(void *p) |
| 2887 | { |
Zhiyuan Dai | 68d68ff | 2021-05-04 18:40:12 -0700 | [diff] [blame] | 2888 | pg_data_t *pgdat = (pg_data_t *)p; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2889 | struct task_struct *tsk = current; |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2890 | unsigned int proactive_defer = 0; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2891 | |
| 2892 | const struct cpumask *cpumask = cpumask_of_node(pgdat->node_id); |
| 2893 | |
| 2894 | if (!cpumask_empty(cpumask)) |
| 2895 | set_cpus_allowed_ptr(tsk, cpumask); |
| 2896 | |
| 2897 | set_freezable(); |
| 2898 | |
| 2899 | pgdat->kcompactd_max_order = 0; |
Joonsoo Kim | 97a225e | 2020-06-03 15:59:01 -0700 | [diff] [blame] | 2900 | pgdat->kcompactd_highest_zoneidx = pgdat->nr_zones - 1; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2901 | |
| 2902 | while (!kthread_should_stop()) { |
Johannes Weiner | eb41468 | 2018-10-26 15:06:27 -0700 | [diff] [blame] | 2903 | unsigned long pflags; |
| 2904 | |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2905 | trace_mm_compaction_kcompactd_sleep(pgdat->node_id); |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2906 | if (wait_event_freezable_timeout(pgdat->kcompactd_wait, |
| 2907 | kcompactd_work_requested(pgdat), |
| 2908 | msecs_to_jiffies(HPAGE_FRAG_CHECK_INTERVAL_MSEC))) { |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2909 | |
Nitin Gupta | facdaa9 | 2020-08-11 18:31:00 -0700 | [diff] [blame] | 2910 | psi_memstall_enter(&pflags); |
| 2911 | kcompactd_do_work(pgdat); |
| 2912 | psi_memstall_leave(&pflags); |
| 2913 | continue; |
| 2914 | } |
| 2915 | |
| 2916 | /* kcompactd wait timeout */ |
| 2917 | if (should_proactive_compact_node(pgdat)) { |
| 2918 | unsigned int prev_score, score; |
| 2919 | |
| 2920 | if (proactive_defer) { |
| 2921 | proactive_defer--; |
| 2922 | continue; |
| 2923 | } |
| 2924 | prev_score = fragmentation_score_node(pgdat); |
| 2925 | proactive_compact_node(pgdat); |
| 2926 | score = fragmentation_score_node(pgdat); |
| 2927 | /* |
| 2928 | * Defer proactive compaction if the fragmentation |
| 2929 | * score did not go down i.e. no progress made. |
| 2930 | */ |
| 2931 | proactive_defer = score < prev_score ? |
| 2932 | 0 : 1 << COMPACT_MAX_DEFER_SHIFT; |
| 2933 | } |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2934 | } |
| 2935 | |
| 2936 | return 0; |
| 2937 | } |
| 2938 | |
| 2939 | /* |
| 2940 | * This kcompactd start function will be called by init and node-hot-add. |
| 2941 | * On node-hot-add, kcompactd will moved to proper cpus if cpus are hot-added. |
| 2942 | */ |
| 2943 | int kcompactd_run(int nid) |
| 2944 | { |
| 2945 | pg_data_t *pgdat = NODE_DATA(nid); |
| 2946 | int ret = 0; |
| 2947 | |
| 2948 | if (pgdat->kcompactd) |
| 2949 | return 0; |
| 2950 | |
| 2951 | pgdat->kcompactd = kthread_run(kcompactd, pgdat, "kcompactd%d", nid); |
| 2952 | if (IS_ERR(pgdat->kcompactd)) { |
| 2953 | pr_err("Failed to start kcompactd on node %d\n", nid); |
| 2954 | ret = PTR_ERR(pgdat->kcompactd); |
| 2955 | pgdat->kcompactd = NULL; |
| 2956 | } |
| 2957 | return ret; |
| 2958 | } |
| 2959 | |
| 2960 | /* |
| 2961 | * Called by memory hotplug when all memory in a node is offlined. Caller must |
| 2962 | * hold mem_hotplug_begin/end(). |
| 2963 | */ |
| 2964 | void kcompactd_stop(int nid) |
| 2965 | { |
| 2966 | struct task_struct *kcompactd = NODE_DATA(nid)->kcompactd; |
| 2967 | |
| 2968 | if (kcompactd) { |
| 2969 | kthread_stop(kcompactd); |
| 2970 | NODE_DATA(nid)->kcompactd = NULL; |
| 2971 | } |
| 2972 | } |
| 2973 | |
| 2974 | /* |
| 2975 | * It's optimal to keep kcompactd on the same CPUs as their memory, but |
| 2976 | * not required for correctness. So if the last cpu in a node goes |
| 2977 | * away, we get changed to run anywhere: as the first one comes back, |
| 2978 | * restore their cpu bindings. |
| 2979 | */ |
Anna-Maria Gleixner | e46b1db | 2016-11-27 00:13:42 +0100 | [diff] [blame] | 2980 | static int kcompactd_cpu_online(unsigned int cpu) |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2981 | { |
| 2982 | int nid; |
| 2983 | |
Anna-Maria Gleixner | e46b1db | 2016-11-27 00:13:42 +0100 | [diff] [blame] | 2984 | for_each_node_state(nid, N_MEMORY) { |
| 2985 | pg_data_t *pgdat = NODE_DATA(nid); |
| 2986 | const struct cpumask *mask; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2987 | |
Anna-Maria Gleixner | e46b1db | 2016-11-27 00:13:42 +0100 | [diff] [blame] | 2988 | mask = cpumask_of_node(pgdat->node_id); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2989 | |
Anna-Maria Gleixner | e46b1db | 2016-11-27 00:13:42 +0100 | [diff] [blame] | 2990 | if (cpumask_any_and(cpu_online_mask, mask) < nr_cpu_ids) |
| 2991 | /* One of our CPUs online: restore mask */ |
| 2992 | set_cpus_allowed_ptr(pgdat->kcompactd, mask); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2993 | } |
Anna-Maria Gleixner | e46b1db | 2016-11-27 00:13:42 +0100 | [diff] [blame] | 2994 | return 0; |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 2995 | } |
| 2996 | |
| 2997 | static int __init kcompactd_init(void) |
| 2998 | { |
| 2999 | int nid; |
Anna-Maria Gleixner | e46b1db | 2016-11-27 00:13:42 +0100 | [diff] [blame] | 3000 | int ret; |
| 3001 | |
| 3002 | ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, |
| 3003 | "mm/compaction:online", |
| 3004 | kcompactd_cpu_online, NULL); |
| 3005 | if (ret < 0) { |
| 3006 | pr_err("kcompactd: failed to register hotplug callbacks.\n"); |
| 3007 | return ret; |
| 3008 | } |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 3009 | |
| 3010 | for_each_node_state(nid, N_MEMORY) |
| 3011 | kcompactd_run(nid); |
Vlastimil Babka | 698b1b3 | 2016-03-17 14:18:08 -0700 | [diff] [blame] | 3012 | return 0; |
| 3013 | } |
| 3014 | subsys_initcall(kcompactd_init) |
| 3015 | |
Michal Nazarewicz | ff9543f | 2011-12-29 13:09:50 +0100 | [diff] [blame] | 3016 | #endif /* CONFIG_COMPACTION */ |