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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
a5d76b54 KH |
2 | /* |
3 | * linux/mm/page_isolation.c | |
4 | */ | |
5 | ||
a5d76b54 KH |
6 | #include <linux/mm.h> |
7 | #include <linux/page-isolation.h> | |
8 | #include <linux/pageblock-flags.h> | |
ee6f509c | 9 | #include <linux/memory.h> |
c8721bbb | 10 | #include <linux/hugetlb.h> |
83358ece | 11 | #include <linux/page_owner.h> |
8b913238 | 12 | #include <linux/migrate.h> |
a5d76b54 KH |
13 | #include "internal.h" |
14 | ||
0f0848e5 JK |
15 | #define CREATE_TRACE_POINTS |
16 | #include <trace/events/page_isolation.h> | |
17 | ||
4da2ce25 | 18 | static int set_migratetype_isolate(struct page *page, int migratetype, |
c5b4e1b0 | 19 | bool skip_hwpoisoned_pages) |
ee6f509c MK |
20 | { |
21 | struct zone *zone; | |
22 | unsigned long flags, pfn; | |
23 | struct memory_isolate_notify arg; | |
24 | int notifier_ret; | |
25 | int ret = -EBUSY; | |
26 | ||
27 | zone = page_zone(page); | |
28 | ||
29 | spin_lock_irqsave(&zone->lock, flags); | |
30 | ||
31 | pfn = page_to_pfn(page); | |
32 | arg.start_pfn = pfn; | |
33 | arg.nr_pages = pageblock_nr_pages; | |
34 | arg.pages_found = 0; | |
35 | ||
36 | /* | |
37 | * It may be possible to isolate a pageblock even if the | |
38 | * migratetype is not MIGRATE_MOVABLE. The memory isolation | |
39 | * notifier chain is used by balloon drivers to return the | |
40 | * number of pages in a range that are held by the balloon | |
41 | * driver to shrink memory. If all the pages are accounted for | |
42 | * by balloons, are free, or on the LRU, isolation can continue. | |
43 | * Later, for example, when memory hotplug notifier runs, these | |
44 | * pages reported as "can be isolated" should be isolated(freed) | |
45 | * by the balloon driver through the memory notifier chain. | |
46 | */ | |
47 | notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg); | |
48 | notifier_ret = notifier_to_errno(notifier_ret); | |
49 | if (notifier_ret) | |
50 | goto out; | |
51 | /* | |
52 | * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. | |
53 | * We just check MOVABLE pages. | |
54 | */ | |
4da2ce25 | 55 | if (!has_unmovable_pages(zone, page, arg.pages_found, migratetype, |
b023f468 | 56 | skip_hwpoisoned_pages)) |
ee6f509c MK |
57 | ret = 0; |
58 | ||
59 | /* | |
ac34dcd2 | 60 | * immobile means "not-on-lru" pages. If immobile is larger than |
ee6f509c MK |
61 | * removable-by-driver pages reported by notifier, we'll fail. |
62 | */ | |
63 | ||
64 | out: | |
65 | if (!ret) { | |
2139cbe6 | 66 | unsigned long nr_pages; |
4da2ce25 | 67 | int mt = get_pageblock_migratetype(page); |
2139cbe6 | 68 | |
a458431e | 69 | set_pageblock_migratetype(page, MIGRATE_ISOLATE); |
ad53f92e | 70 | zone->nr_isolate_pageblock++; |
02aa0cdd VB |
71 | nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE, |
72 | NULL); | |
2139cbe6 | 73 | |
4da2ce25 | 74 | __mod_zone_freepage_state(zone, -nr_pages, mt); |
ee6f509c MK |
75 | } |
76 | ||
77 | spin_unlock_irqrestore(&zone->lock, flags); | |
78 | if (!ret) | |
ec25af84 | 79 | drain_all_pages(zone); |
ee6f509c MK |
80 | return ret; |
81 | } | |
82 | ||
c5b4e1b0 | 83 | static void unset_migratetype_isolate(struct page *page, unsigned migratetype) |
ee6f509c MK |
84 | { |
85 | struct zone *zone; | |
2139cbe6 | 86 | unsigned long flags, nr_pages; |
e3a2713c | 87 | bool isolated_page = false; |
3c605096 | 88 | unsigned int order; |
76741e77 | 89 | unsigned long pfn, buddy_pfn; |
3c605096 | 90 | struct page *buddy; |
2139cbe6 | 91 | |
ee6f509c MK |
92 | zone = page_zone(page); |
93 | spin_lock_irqsave(&zone->lock, flags); | |
bbf9ce97 | 94 | if (!is_migrate_isolate_page(page)) |
ee6f509c | 95 | goto out; |
3c605096 JK |
96 | |
97 | /* | |
98 | * Because freepage with more than pageblock_order on isolated | |
99 | * pageblock is restricted to merge due to freepage counting problem, | |
100 | * it is possible that there is free buddy page. | |
101 | * move_freepages_block() doesn't care of merge so we need other | |
102 | * approach in order to merge them. Isolation and free will make | |
103 | * these pages to be merged. | |
104 | */ | |
105 | if (PageBuddy(page)) { | |
106 | order = page_order(page); | |
107 | if (order >= pageblock_order) { | |
76741e77 VB |
108 | pfn = page_to_pfn(page); |
109 | buddy_pfn = __find_buddy_pfn(pfn, order); | |
110 | buddy = page + (buddy_pfn - pfn); | |
3c605096 | 111 | |
13ad59df | 112 | if (pfn_valid_within(buddy_pfn) && |
1ae7013d | 113 | !is_migrate_isolate_page(buddy)) { |
3c605096 | 114 | __isolate_free_page(page, order); |
e3a2713c | 115 | isolated_page = true; |
3c605096 JK |
116 | } |
117 | } | |
118 | } | |
119 | ||
120 | /* | |
121 | * If we isolate freepage with more than pageblock_order, there | |
122 | * should be no freepage in the range, so we could avoid costly | |
123 | * pageblock scanning for freepage moving. | |
124 | */ | |
125 | if (!isolated_page) { | |
02aa0cdd | 126 | nr_pages = move_freepages_block(zone, page, migratetype, NULL); |
3c605096 JK |
127 | __mod_zone_freepage_state(zone, nr_pages, migratetype); |
128 | } | |
a458431e | 129 | set_pageblock_migratetype(page, migratetype); |
ad53f92e | 130 | zone->nr_isolate_pageblock--; |
ee6f509c MK |
131 | out: |
132 | spin_unlock_irqrestore(&zone->lock, flags); | |
83358ece | 133 | if (isolated_page) { |
46f24fd8 | 134 | post_alloc_hook(page, order, __GFP_MOVABLE); |
e3a2713c | 135 | __free_pages(page, order); |
83358ece | 136 | } |
ee6f509c MK |
137 | } |
138 | ||
a5d76b54 KH |
139 | static inline struct page * |
140 | __first_valid_page(unsigned long pfn, unsigned long nr_pages) | |
141 | { | |
142 | int i; | |
2ce13640 MH |
143 | |
144 | for (i = 0; i < nr_pages; i++) { | |
145 | struct page *page; | |
146 | ||
147 | if (!pfn_valid_within(pfn + i)) | |
148 | continue; | |
149 | page = pfn_to_online_page(pfn + i); | |
150 | if (!page) | |
151 | continue; | |
152 | return page; | |
153 | } | |
154 | return NULL; | |
a5d76b54 KH |
155 | } |
156 | ||
157 | /* | |
158 | * start_isolate_page_range() -- make page-allocation-type of range of pages | |
159 | * to be MIGRATE_ISOLATE. | |
160 | * @start_pfn: The lower PFN of the range to be isolated. | |
161 | * @end_pfn: The upper PFN of the range to be isolated. | |
0815f3d8 | 162 | * @migratetype: migrate type to set in error recovery. |
a5d76b54 KH |
163 | * |
164 | * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in | |
165 | * the range will never be allocated. Any free pages and pages freed in the | |
166 | * future will not be allocated again. | |
167 | * | |
168 | * start_pfn/end_pfn must be aligned to pageblock_order. | |
169 | * Returns 0 on success and -EBUSY if any part of range cannot be isolated. | |
170 | */ | |
0815f3d8 | 171 | int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
b023f468 | 172 | unsigned migratetype, bool skip_hwpoisoned_pages) |
a5d76b54 KH |
173 | { |
174 | unsigned long pfn; | |
175 | unsigned long undo_pfn; | |
176 | struct page *page; | |
177 | ||
fec174d6 NH |
178 | BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); |
179 | BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages)); | |
a5d76b54 KH |
180 | |
181 | for (pfn = start_pfn; | |
182 | pfn < end_pfn; | |
183 | pfn += pageblock_nr_pages) { | |
184 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
b023f468 | 185 | if (page && |
4da2ce25 | 186 | set_migratetype_isolate(page, migratetype, skip_hwpoisoned_pages)) { |
a5d76b54 KH |
187 | undo_pfn = pfn; |
188 | goto undo; | |
189 | } | |
190 | } | |
191 | return 0; | |
192 | undo: | |
193 | for (pfn = start_pfn; | |
dbc0e4ce | 194 | pfn < undo_pfn; |
2ce13640 MH |
195 | pfn += pageblock_nr_pages) { |
196 | struct page *page = pfn_to_online_page(pfn); | |
197 | if (!page) | |
198 | continue; | |
199 | unset_migratetype_isolate(page, migratetype); | |
200 | } | |
a5d76b54 KH |
201 | |
202 | return -EBUSY; | |
203 | } | |
204 | ||
205 | /* | |
206 | * Make isolated pages available again. | |
207 | */ | |
0815f3d8 MN |
208 | int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
209 | unsigned migratetype) | |
a5d76b54 KH |
210 | { |
211 | unsigned long pfn; | |
212 | struct page *page; | |
6f8d2b8a WX |
213 | |
214 | BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); | |
215 | BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages)); | |
216 | ||
a5d76b54 KH |
217 | for (pfn = start_pfn; |
218 | pfn < end_pfn; | |
219 | pfn += pageblock_nr_pages) { | |
220 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
bbf9ce97 | 221 | if (!page || !is_migrate_isolate_page(page)) |
a5d76b54 | 222 | continue; |
0815f3d8 | 223 | unset_migratetype_isolate(page, migratetype); |
a5d76b54 KH |
224 | } |
225 | return 0; | |
226 | } | |
227 | /* | |
228 | * Test all pages in the range is free(means isolated) or not. | |
229 | * all pages in [start_pfn...end_pfn) must be in the same zone. | |
230 | * zone->lock must be held before call this. | |
231 | * | |
ec3b6882 | 232 | * Returns the last tested pfn. |
a5d76b54 | 233 | */ |
fea85cff | 234 | static unsigned long |
b023f468 WC |
235 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, |
236 | bool skip_hwpoisoned_pages) | |
a5d76b54 KH |
237 | { |
238 | struct page *page; | |
239 | ||
240 | while (pfn < end_pfn) { | |
241 | if (!pfn_valid_within(pfn)) { | |
242 | pfn++; | |
243 | continue; | |
244 | } | |
245 | page = pfn_to_page(pfn); | |
aa016d14 | 246 | if (PageBuddy(page)) |
435b405c | 247 | /* |
aa016d14 VB |
248 | * If the page is on a free list, it has to be on |
249 | * the correct MIGRATE_ISOLATE freelist. There is no | |
250 | * simple way to verify that as VM_BUG_ON(), though. | |
435b405c | 251 | */ |
a5d76b54 | 252 | pfn += 1 << page_order(page); |
aa016d14 VB |
253 | else if (skip_hwpoisoned_pages && PageHWPoison(page)) |
254 | /* A HWPoisoned page cannot be also PageBuddy */ | |
b023f468 | 255 | pfn++; |
a5d76b54 KH |
256 | else |
257 | break; | |
258 | } | |
fea85cff JK |
259 | |
260 | return pfn; | |
a5d76b54 KH |
261 | } |
262 | ||
b9eb6319 | 263 | /* Caller should ensure that requested range is in a single zone */ |
b023f468 WC |
264 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn, |
265 | bool skip_hwpoisoned_pages) | |
a5d76b54 | 266 | { |
6c1b7f68 | 267 | unsigned long pfn, flags; |
a5d76b54 | 268 | struct page *page; |
6c1b7f68 | 269 | struct zone *zone; |
a5d76b54 | 270 | |
a5d76b54 | 271 | /* |
85dbe706 TC |
272 | * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages |
273 | * are not aligned to pageblock_nr_pages. | |
274 | * Then we just check migratetype first. | |
a5d76b54 KH |
275 | */ |
276 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
277 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
bbf9ce97 | 278 | if (page && !is_migrate_isolate_page(page)) |
a5d76b54 KH |
279 | break; |
280 | } | |
a70dcb96 GS |
281 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
282 | if ((pfn < end_pfn) || !page) | |
a5d76b54 | 283 | return -EBUSY; |
85dbe706 | 284 | /* Check all pages are free or marked as ISOLATED */ |
a70dcb96 | 285 | zone = page_zone(page); |
6c1b7f68 | 286 | spin_lock_irqsave(&zone->lock, flags); |
fea85cff | 287 | pfn = __test_page_isolated_in_pageblock(start_pfn, end_pfn, |
b023f468 | 288 | skip_hwpoisoned_pages); |
6c1b7f68 | 289 | spin_unlock_irqrestore(&zone->lock, flags); |
fea85cff | 290 | |
0f0848e5 JK |
291 | trace_test_pages_isolated(start_pfn, end_pfn, pfn); |
292 | ||
fea85cff | 293 | return pfn < end_pfn ? -EBUSY : 0; |
a5d76b54 | 294 | } |
723a0644 MK |
295 | |
296 | struct page *alloc_migrate_target(struct page *page, unsigned long private, | |
297 | int **resultp) | |
298 | { | |
8b913238 | 299 | return new_page_nodemask(page, numa_node_id(), &node_states[N_MEMORY]); |
723a0644 | 300 | } |