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KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -07001/*
2 * linux/mm/page_isolation.c
3 */
4
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -07005#include <linux/mm.h>
6#include <linux/page-isolation.h>
7#include <linux/pageblock-flags.h>
Minchan Kimee6f5092012-07-31 16:43:50 -07008#include <linux/memory.h>
Naoya Horiguchic8721bb2013-09-11 14:22:09 -07009#include <linux/hugetlb.h>
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -070010#include "internal.h"
11
Wen Congyangb023f462012-12-11 16:00:45 -080012int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages)
Minchan Kimee6f5092012-07-31 16:43:50 -070013{
14 struct zone *zone;
15 unsigned long flags, pfn;
16 struct memory_isolate_notify arg;
17 int notifier_ret;
18 int ret = -EBUSY;
19
20 zone = page_zone(page);
21
22 spin_lock_irqsave(&zone->lock, flags);
23
24 pfn = page_to_pfn(page);
25 arg.start_pfn = pfn;
26 arg.nr_pages = pageblock_nr_pages;
27 arg.pages_found = 0;
28
29 /*
30 * It may be possible to isolate a pageblock even if the
31 * migratetype is not MIGRATE_MOVABLE. The memory isolation
32 * notifier chain is used by balloon drivers to return the
33 * number of pages in a range that are held by the balloon
34 * driver to shrink memory. If all the pages are accounted for
35 * by balloons, are free, or on the LRU, isolation can continue.
36 * Later, for example, when memory hotplug notifier runs, these
37 * pages reported as "can be isolated" should be isolated(freed)
38 * by the balloon driver through the memory notifier chain.
39 */
40 notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg);
41 notifier_ret = notifier_to_errno(notifier_ret);
42 if (notifier_ret)
43 goto out;
44 /*
45 * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself.
46 * We just check MOVABLE pages.
47 */
Wen Congyangb023f462012-12-11 16:00:45 -080048 if (!has_unmovable_pages(zone, page, arg.pages_found,
49 skip_hwpoisoned_pages))
Minchan Kimee6f5092012-07-31 16:43:50 -070050 ret = 0;
51
52 /*
53 * immobile means "not-on-lru" paes. If immobile is larger than
54 * removable-by-driver pages reported by notifier, we'll fail.
55 */
56
57out:
58 if (!ret) {
Bartlomiej Zolnierkiewicz2139cbe2012-10-08 16:32:00 -070059 unsigned long nr_pages;
Bartlomiej Zolnierkiewiczd1ce7492012-10-08 16:32:02 -070060 int migratetype = get_pageblock_migratetype(page);
Bartlomiej Zolnierkiewicz2139cbe2012-10-08 16:32:00 -070061
Bartlomiej Zolnierkiewicza4584312013-01-04 15:35:08 -080062 set_pageblock_migratetype(page, MIGRATE_ISOLATE);
Joonsoo Kimad53f922014-11-13 15:19:11 -080063 zone->nr_isolate_pageblock++;
Bartlomiej Zolnierkiewicz2139cbe2012-10-08 16:32:00 -070064 nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE);
65
Bartlomiej Zolnierkiewiczd1ce7492012-10-08 16:32:02 -070066 __mod_zone_freepage_state(zone, -nr_pages, migratetype);
Minchan Kimee6f5092012-07-31 16:43:50 -070067 }
68
69 spin_unlock_irqrestore(&zone->lock, flags);
70 if (!ret)
Vlastimil Babkaec25af82014-12-10 15:43:04 -080071 drain_all_pages(zone);
Minchan Kimee6f5092012-07-31 16:43:50 -070072 return ret;
73}
74
75void unset_migratetype_isolate(struct page *page, unsigned migratetype)
76{
77 struct zone *zone;
Bartlomiej Zolnierkiewicz2139cbe2012-10-08 16:32:00 -070078 unsigned long flags, nr_pages;
Joonsoo Kim3c605092014-11-13 15:19:21 -080079 struct page *isolated_page = NULL;
80 unsigned int order;
81 unsigned long page_idx, buddy_idx;
82 struct page *buddy;
Bartlomiej Zolnierkiewicz2139cbe2012-10-08 16:32:00 -070083
Minchan Kimee6f5092012-07-31 16:43:50 -070084 zone = page_zone(page);
85 spin_lock_irqsave(&zone->lock, flags);
86 if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
87 goto out;
Joonsoo Kim3c605092014-11-13 15:19:21 -080088
89 /*
90 * Because freepage with more than pageblock_order on isolated
91 * pageblock is restricted to merge due to freepage counting problem,
92 * it is possible that there is free buddy page.
93 * move_freepages_block() doesn't care of merge so we need other
94 * approach in order to merge them. Isolation and free will make
95 * these pages to be merged.
96 */
97 if (PageBuddy(page)) {
98 order = page_order(page);
99 if (order >= pageblock_order) {
100 page_idx = page_to_pfn(page) & ((1 << MAX_ORDER) - 1);
101 buddy_idx = __find_buddy_index(page_idx, order);
102 buddy = page + (buddy_idx - page_idx);
103
104 if (!is_migrate_isolate_page(buddy)) {
105 __isolate_free_page(page, order);
Laura Abbottcfa86942015-03-25 15:55:26 -0700106 kernel_map_pages(page, (1 << order), 1);
Joonsoo Kim3c605092014-11-13 15:19:21 -0800107 set_page_refcounted(page);
108 isolated_page = page;
109 }
110 }
111 }
112
113 /*
114 * If we isolate freepage with more than pageblock_order, there
115 * should be no freepage in the range, so we could avoid costly
116 * pageblock scanning for freepage moving.
117 */
118 if (!isolated_page) {
119 nr_pages = move_freepages_block(zone, page, migratetype);
120 __mod_zone_freepage_state(zone, nr_pages, migratetype);
121 }
Bartlomiej Zolnierkiewicza4584312013-01-04 15:35:08 -0800122 set_pageblock_migratetype(page, migratetype);
Joonsoo Kimad53f922014-11-13 15:19:11 -0800123 zone->nr_isolate_pageblock--;
Minchan Kimee6f5092012-07-31 16:43:50 -0700124out:
125 spin_unlock_irqrestore(&zone->lock, flags);
Joonsoo Kim3c605092014-11-13 15:19:21 -0800126 if (isolated_page)
127 __free_pages(isolated_page, order);
Minchan Kimee6f5092012-07-31 16:43:50 -0700128}
129
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700130static inline struct page *
131__first_valid_page(unsigned long pfn, unsigned long nr_pages)
132{
133 int i;
134 for (i = 0; i < nr_pages; i++)
135 if (pfn_valid_within(pfn + i))
136 break;
137 if (unlikely(i == nr_pages))
138 return NULL;
139 return pfn_to_page(pfn + i);
140}
141
142/*
143 * start_isolate_page_range() -- make page-allocation-type of range of pages
144 * to be MIGRATE_ISOLATE.
145 * @start_pfn: The lower PFN of the range to be isolated.
146 * @end_pfn: The upper PFN of the range to be isolated.
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200147 * @migratetype: migrate type to set in error recovery.
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700148 *
149 * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
150 * the range will never be allocated. Any free pages and pages freed in the
151 * future will not be allocated again.
152 *
153 * start_pfn/end_pfn must be aligned to pageblock_order.
154 * Returns 0 on success and -EBUSY if any part of range cannot be isolated.
155 */
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200156int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
Wen Congyangb023f462012-12-11 16:00:45 -0800157 unsigned migratetype, bool skip_hwpoisoned_pages)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700158{
159 unsigned long pfn;
160 unsigned long undo_pfn;
161 struct page *page;
162
163 BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
164 BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
165
166 for (pfn = start_pfn;
167 pfn < end_pfn;
168 pfn += pageblock_nr_pages) {
169 page = __first_valid_page(pfn, pageblock_nr_pages);
Wen Congyangb023f462012-12-11 16:00:45 -0800170 if (page &&
171 set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700172 undo_pfn = pfn;
173 goto undo;
174 }
175 }
176 return 0;
177undo:
178 for (pfn = start_pfn;
KAMEZAWA Hiroyukidbc0e4c2007-11-14 16:59:12 -0800179 pfn < undo_pfn;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700180 pfn += pageblock_nr_pages)
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200181 unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700182
183 return -EBUSY;
184}
185
186/*
187 * Make isolated pages available again.
188 */
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200189int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
190 unsigned migratetype)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700191{
192 unsigned long pfn;
193 struct page *page;
194 BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
195 BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
196 for (pfn = start_pfn;
197 pfn < end_pfn;
198 pfn += pageblock_nr_pages) {
199 page = __first_valid_page(pfn, pageblock_nr_pages);
KAMEZAWA Hiroyukidbc0e4c2007-11-14 16:59:12 -0800200 if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700201 continue;
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200202 unset_migratetype_isolate(page, migratetype);
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700203 }
204 return 0;
205}
206/*
207 * Test all pages in the range is free(means isolated) or not.
208 * all pages in [start_pfn...end_pfn) must be in the same zone.
209 * zone->lock must be held before call this.
210 *
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200211 * Returns 1 if all pages in the range are isolated.
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700212 */
213static int
Wen Congyangb023f462012-12-11 16:00:45 -0800214__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
215 bool skip_hwpoisoned_pages)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700216{
217 struct page *page;
218
219 while (pfn < end_pfn) {
220 if (!pfn_valid_within(pfn)) {
221 pfn++;
222 continue;
223 }
224 page = pfn_to_page(pfn);
Minchan Kim41d575a2012-10-08 16:32:14 -0700225 if (PageBuddy(page)) {
Minchan Kim435b4052012-10-08 16:32:16 -0700226 /*
227 * If race between isolatation and allocation happens,
228 * some free pages could be in MIGRATE_MOVABLE list
229 * although pageblock's migratation type of the page
230 * is MIGRATE_ISOLATE. Catch it and move the page into
231 * MIGRATE_ISOLATE list.
232 */
233 if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) {
234 struct page *end_page;
235
236 end_page = page + (1 << page_order(page)) - 1;
237 move_freepages(page_zone(page), page, end_page,
238 MIGRATE_ISOLATE);
239 }
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700240 pfn += 1 << page_order(page);
Minchan Kim41d575a2012-10-08 16:32:14 -0700241 }
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700242 else if (page_count(page) == 0 &&
Minchan Kimb12c4ad2012-10-08 16:32:08 -0700243 get_freepage_migratetype(page) == MIGRATE_ISOLATE)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700244 pfn += 1;
Wen Congyangb023f462012-12-11 16:00:45 -0800245 else if (skip_hwpoisoned_pages && PageHWPoison(page)) {
246 /*
247 * The HWPoisoned page may be not in buddy
248 * system, and page_count() is not 0.
249 */
250 pfn++;
251 continue;
252 }
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700253 else
254 break;
255 }
256 if (pfn < end_pfn)
257 return 0;
258 return 1;
259}
260
Wen Congyangb023f462012-12-11 16:00:45 -0800261int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
262 bool skip_hwpoisoned_pages)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700263{
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700264 unsigned long pfn, flags;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700265 struct page *page;
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700266 struct zone *zone;
267 int ret;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700268
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700269 /*
Tang Chen85dbe702013-06-20 18:10:19 +0800270 * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages
271 * are not aligned to pageblock_nr_pages.
272 * Then we just check migratetype first.
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700273 */
274 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
275 page = __first_valid_page(pfn, pageblock_nr_pages);
KAMEZAWA Hiroyukidbc0e4c2007-11-14 16:59:12 -0800276 if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700277 break;
278 }
Gerald Schaefera70dcb92008-11-06 12:53:36 -0800279 page = __first_valid_page(start_pfn, end_pfn - start_pfn);
280 if ((pfn < end_pfn) || !page)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700281 return -EBUSY;
Tang Chen85dbe702013-06-20 18:10:19 +0800282 /* Check all pages are free or marked as ISOLATED */
Gerald Schaefera70dcb92008-11-06 12:53:36 -0800283 zone = page_zone(page);
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700284 spin_lock_irqsave(&zone->lock, flags);
Wen Congyangb023f462012-12-11 16:00:45 -0800285 ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
286 skip_hwpoisoned_pages);
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700287 spin_unlock_irqrestore(&zone->lock, flags);
288 return ret ? 0 : -EBUSY;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700289}
Minchan Kim723a0642012-10-08 16:32:52 -0700290
291struct page *alloc_migrate_target(struct page *page, unsigned long private,
292 int **resultp)
293{
294 gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
295
Naoya Horiguchic8721bb2013-09-11 14:22:09 -0700296 /*
297 * TODO: allocate a destination hugepage from a nearest neighbor node,
298 * accordance with memory policy of the user process if possible. For
299 * now as a simple work-around, we use the next node for destination.
300 */
301 if (PageHuge(page)) {
302 nodemask_t src = nodemask_of_node(page_to_nid(page));
303 nodemask_t dst;
304 nodes_complement(dst, src);
305 return alloc_huge_page_node(page_hstate(compound_head(page)),
306 next_node(page_to_nid(page), dst));
307 }
308
Minchan Kim723a0642012-10-08 16:32:52 -0700309 if (PageHighMem(page))
310 gfp_mask |= __GFP_HIGHMEM;
311
312 return alloc_page(gfp_mask);
313}