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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)
71 drain_all_pages();
72 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);
106 set_page_refcounted(page);
107 isolated_page = page;
108 }
109 }
110 }
111
112 /*
113 * If we isolate freepage with more than pageblock_order, there
114 * should be no freepage in the range, so we could avoid costly
115 * pageblock scanning for freepage moving.
116 */
117 if (!isolated_page) {
118 nr_pages = move_freepages_block(zone, page, migratetype);
119 __mod_zone_freepage_state(zone, nr_pages, migratetype);
120 }
Bartlomiej Zolnierkiewicza4584312013-01-04 15:35:08 -0800121 set_pageblock_migratetype(page, migratetype);
Joonsoo Kimad53f922014-11-13 15:19:11 -0800122 zone->nr_isolate_pageblock--;
Minchan Kimee6f5092012-07-31 16:43:50 -0700123out:
124 spin_unlock_irqrestore(&zone->lock, flags);
Joonsoo Kim3c605092014-11-13 15:19:21 -0800125 if (isolated_page)
126 __free_pages(isolated_page, order);
Minchan Kimee6f5092012-07-31 16:43:50 -0700127}
128
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700129static inline struct page *
130__first_valid_page(unsigned long pfn, unsigned long nr_pages)
131{
132 int i;
133 for (i = 0; i < nr_pages; i++)
134 if (pfn_valid_within(pfn + i))
135 break;
136 if (unlikely(i == nr_pages))
137 return NULL;
138 return pfn_to_page(pfn + i);
139}
140
141/*
142 * start_isolate_page_range() -- make page-allocation-type of range of pages
143 * to be MIGRATE_ISOLATE.
144 * @start_pfn: The lower PFN of the range to be isolated.
145 * @end_pfn: The upper PFN of the range to be isolated.
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200146 * @migratetype: migrate type to set in error recovery.
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700147 *
148 * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
149 * the range will never be allocated. Any free pages and pages freed in the
150 * future will not be allocated again.
151 *
152 * start_pfn/end_pfn must be aligned to pageblock_order.
153 * Returns 0 on success and -EBUSY if any part of range cannot be isolated.
154 */
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200155int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
Wen Congyangb023f462012-12-11 16:00:45 -0800156 unsigned migratetype, bool skip_hwpoisoned_pages)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700157{
158 unsigned long pfn;
159 unsigned long undo_pfn;
160 struct page *page;
161
162 BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
163 BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
164
165 for (pfn = start_pfn;
166 pfn < end_pfn;
167 pfn += pageblock_nr_pages) {
168 page = __first_valid_page(pfn, pageblock_nr_pages);
Wen Congyangb023f462012-12-11 16:00:45 -0800169 if (page &&
170 set_migratetype_isolate(page, skip_hwpoisoned_pages)) {
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700171 undo_pfn = pfn;
172 goto undo;
173 }
174 }
175 return 0;
176undo:
177 for (pfn = start_pfn;
KAMEZAWA Hiroyukidbc0e4c2007-11-14 16:59:12 -0800178 pfn < undo_pfn;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700179 pfn += pageblock_nr_pages)
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200180 unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700181
182 return -EBUSY;
183}
184
185/*
186 * Make isolated pages available again.
187 */
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200188int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
189 unsigned migratetype)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700190{
191 unsigned long pfn;
192 struct page *page;
193 BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
194 BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
195 for (pfn = start_pfn;
196 pfn < end_pfn;
197 pfn += pageblock_nr_pages) {
198 page = __first_valid_page(pfn, pageblock_nr_pages);
KAMEZAWA Hiroyukidbc0e4c2007-11-14 16:59:12 -0800199 if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700200 continue;
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200201 unset_migratetype_isolate(page, migratetype);
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700202 }
203 return 0;
204}
205/*
206 * Test all pages in the range is free(means isolated) or not.
207 * all pages in [start_pfn...end_pfn) must be in the same zone.
208 * zone->lock must be held before call this.
209 *
Michal Nazarewicz0815f3d2012-04-03 15:06:15 +0200210 * Returns 1 if all pages in the range are isolated.
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700211 */
212static int
Wen Congyangb023f462012-12-11 16:00:45 -0800213__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
214 bool skip_hwpoisoned_pages)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700215{
216 struct page *page;
217
218 while (pfn < end_pfn) {
219 if (!pfn_valid_within(pfn)) {
220 pfn++;
221 continue;
222 }
223 page = pfn_to_page(pfn);
Minchan Kim41d575a2012-10-08 16:32:14 -0700224 if (PageBuddy(page)) {
Minchan Kim435b4052012-10-08 16:32:16 -0700225 /*
226 * If race between isolatation and allocation happens,
227 * some free pages could be in MIGRATE_MOVABLE list
228 * although pageblock's migratation type of the page
229 * is MIGRATE_ISOLATE. Catch it and move the page into
230 * MIGRATE_ISOLATE list.
231 */
232 if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) {
233 struct page *end_page;
234
235 end_page = page + (1 << page_order(page)) - 1;
236 move_freepages(page_zone(page), page, end_page,
237 MIGRATE_ISOLATE);
238 }
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700239 pfn += 1 << page_order(page);
Minchan Kim41d575a2012-10-08 16:32:14 -0700240 }
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700241 else if (page_count(page) == 0 &&
Minchan Kimb12c4ad2012-10-08 16:32:08 -0700242 get_freepage_migratetype(page) == MIGRATE_ISOLATE)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700243 pfn += 1;
Wen Congyangb023f462012-12-11 16:00:45 -0800244 else if (skip_hwpoisoned_pages && PageHWPoison(page)) {
245 /*
246 * The HWPoisoned page may be not in buddy
247 * system, and page_count() is not 0.
248 */
249 pfn++;
250 continue;
251 }
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700252 else
253 break;
254 }
255 if (pfn < end_pfn)
256 return 0;
257 return 1;
258}
259
Wen Congyangb023f462012-12-11 16:00:45 -0800260int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
261 bool skip_hwpoisoned_pages)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700262{
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700263 unsigned long pfn, flags;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700264 struct page *page;
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700265 struct zone *zone;
266 int ret;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700267
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700268 /*
Tang Chen85dbe702013-06-20 18:10:19 +0800269 * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages
270 * are not aligned to pageblock_nr_pages.
271 * Then we just check migratetype first.
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700272 */
273 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
274 page = __first_valid_page(pfn, pageblock_nr_pages);
KAMEZAWA Hiroyukidbc0e4c2007-11-14 16:59:12 -0800275 if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700276 break;
277 }
Gerald Schaefera70dcb92008-11-06 12:53:36 -0800278 page = __first_valid_page(start_pfn, end_pfn - start_pfn);
279 if ((pfn < end_pfn) || !page)
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700280 return -EBUSY;
Tang Chen85dbe702013-06-20 18:10:19 +0800281 /* Check all pages are free or marked as ISOLATED */
Gerald Schaefera70dcb92008-11-06 12:53:36 -0800282 zone = page_zone(page);
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700283 spin_lock_irqsave(&zone->lock, flags);
Wen Congyangb023f462012-12-11 16:00:45 -0800284 ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn,
285 skip_hwpoisoned_pages);
Gerald Schaefer6c1b7f62008-10-02 14:50:16 -0700286 spin_unlock_irqrestore(&zone->lock, flags);
287 return ret ? 0 : -EBUSY;
KAMEZAWA Hiroyukia5d76b52007-10-16 01:26:11 -0700288}
Minchan Kim723a0642012-10-08 16:32:52 -0700289
290struct page *alloc_migrate_target(struct page *page, unsigned long private,
291 int **resultp)
292{
293 gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE;
294
Naoya Horiguchic8721bb2013-09-11 14:22:09 -0700295 /*
296 * TODO: allocate a destination hugepage from a nearest neighbor node,
297 * accordance with memory policy of the user process if possible. For
298 * now as a simple work-around, we use the next node for destination.
299 */
300 if (PageHuge(page)) {
301 nodemask_t src = nodemask_of_node(page_to_nid(page));
302 nodemask_t dst;
303 nodes_complement(dst, src);
304 return alloc_huge_page_node(page_hstate(compound_head(page)),
305 next_node(page_to_nid(page), dst));
306 }
307
Minchan Kim723a0642012-10-08 16:32:52 -0700308 if (PageHighMem(page))
309 gfp_mask |= __GFP_HIGHMEM;
310
311 return alloc_page(gfp_mask);
312}