Commit | Line | Data |
---|---|---|
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 | ||
2c7452a0 MK |
31 | /* |
32 | * We assume the caller intended to SET migrate type to isolate. | |
33 | * If it is already set, then someone else must have raced and | |
34 | * set it before us. Return -EBUSY | |
35 | */ | |
36 | if (is_migrate_isolate_page(page)) | |
37 | goto out; | |
38 | ||
ee6f509c MK |
39 | pfn = page_to_pfn(page); |
40 | arg.start_pfn = pfn; | |
41 | arg.nr_pages = pageblock_nr_pages; | |
42 | arg.pages_found = 0; | |
43 | ||
44 | /* | |
45 | * It may be possible to isolate a pageblock even if the | |
46 | * migratetype is not MIGRATE_MOVABLE. The memory isolation | |
47 | * notifier chain is used by balloon drivers to return the | |
48 | * number of pages in a range that are held by the balloon | |
49 | * driver to shrink memory. If all the pages are accounted for | |
50 | * by balloons, are free, or on the LRU, isolation can continue. | |
51 | * Later, for example, when memory hotplug notifier runs, these | |
52 | * pages reported as "can be isolated" should be isolated(freed) | |
53 | * by the balloon driver through the memory notifier chain. | |
54 | */ | |
55 | notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg); | |
56 | notifier_ret = notifier_to_errno(notifier_ret); | |
57 | if (notifier_ret) | |
58 | goto out; | |
59 | /* | |
60 | * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. | |
61 | * We just check MOVABLE pages. | |
62 | */ | |
4da2ce25 | 63 | if (!has_unmovable_pages(zone, page, arg.pages_found, migratetype, |
b023f468 | 64 | skip_hwpoisoned_pages)) |
ee6f509c MK |
65 | ret = 0; |
66 | ||
67 | /* | |
ac34dcd2 | 68 | * immobile means "not-on-lru" pages. If immobile is larger than |
ee6f509c MK |
69 | * removable-by-driver pages reported by notifier, we'll fail. |
70 | */ | |
71 | ||
72 | out: | |
73 | if (!ret) { | |
2139cbe6 | 74 | unsigned long nr_pages; |
4da2ce25 | 75 | int mt = get_pageblock_migratetype(page); |
2139cbe6 | 76 | |
a458431e | 77 | set_pageblock_migratetype(page, MIGRATE_ISOLATE); |
ad53f92e | 78 | zone->nr_isolate_pageblock++; |
02aa0cdd VB |
79 | nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE, |
80 | NULL); | |
2139cbe6 | 81 | |
4da2ce25 | 82 | __mod_zone_freepage_state(zone, -nr_pages, mt); |
ee6f509c MK |
83 | } |
84 | ||
85 | spin_unlock_irqrestore(&zone->lock, flags); | |
86 | if (!ret) | |
ec25af84 | 87 | drain_all_pages(zone); |
ee6f509c MK |
88 | return ret; |
89 | } | |
90 | ||
c5b4e1b0 | 91 | static void unset_migratetype_isolate(struct page *page, unsigned migratetype) |
ee6f509c MK |
92 | { |
93 | struct zone *zone; | |
2139cbe6 | 94 | unsigned long flags, nr_pages; |
e3a2713c | 95 | bool isolated_page = false; |
3c605096 | 96 | unsigned int order; |
76741e77 | 97 | unsigned long pfn, buddy_pfn; |
3c605096 | 98 | struct page *buddy; |
2139cbe6 | 99 | |
ee6f509c MK |
100 | zone = page_zone(page); |
101 | spin_lock_irqsave(&zone->lock, flags); | |
bbf9ce97 | 102 | if (!is_migrate_isolate_page(page)) |
ee6f509c | 103 | goto out; |
3c605096 JK |
104 | |
105 | /* | |
106 | * Because freepage with more than pageblock_order on isolated | |
107 | * pageblock is restricted to merge due to freepage counting problem, | |
108 | * it is possible that there is free buddy page. | |
109 | * move_freepages_block() doesn't care of merge so we need other | |
110 | * approach in order to merge them. Isolation and free will make | |
111 | * these pages to be merged. | |
112 | */ | |
113 | if (PageBuddy(page)) { | |
114 | order = page_order(page); | |
115 | if (order >= pageblock_order) { | |
76741e77 VB |
116 | pfn = page_to_pfn(page); |
117 | buddy_pfn = __find_buddy_pfn(pfn, order); | |
118 | buddy = page + (buddy_pfn - pfn); | |
3c605096 | 119 | |
13ad59df | 120 | if (pfn_valid_within(buddy_pfn) && |
1ae7013d | 121 | !is_migrate_isolate_page(buddy)) { |
3c605096 | 122 | __isolate_free_page(page, order); |
e3a2713c | 123 | isolated_page = true; |
3c605096 JK |
124 | } |
125 | } | |
126 | } | |
127 | ||
128 | /* | |
129 | * If we isolate freepage with more than pageblock_order, there | |
130 | * should be no freepage in the range, so we could avoid costly | |
131 | * pageblock scanning for freepage moving. | |
132 | */ | |
133 | if (!isolated_page) { | |
02aa0cdd | 134 | nr_pages = move_freepages_block(zone, page, migratetype, NULL); |
3c605096 JK |
135 | __mod_zone_freepage_state(zone, nr_pages, migratetype); |
136 | } | |
a458431e | 137 | set_pageblock_migratetype(page, migratetype); |
ad53f92e | 138 | zone->nr_isolate_pageblock--; |
ee6f509c MK |
139 | out: |
140 | spin_unlock_irqrestore(&zone->lock, flags); | |
83358ece | 141 | if (isolated_page) { |
46f24fd8 | 142 | post_alloc_hook(page, order, __GFP_MOVABLE); |
e3a2713c | 143 | __free_pages(page, order); |
83358ece | 144 | } |
ee6f509c MK |
145 | } |
146 | ||
a5d76b54 KH |
147 | static inline struct page * |
148 | __first_valid_page(unsigned long pfn, unsigned long nr_pages) | |
149 | { | |
150 | int i; | |
2ce13640 MH |
151 | |
152 | for (i = 0; i < nr_pages; i++) { | |
153 | struct page *page; | |
154 | ||
155 | if (!pfn_valid_within(pfn + i)) | |
156 | continue; | |
157 | page = pfn_to_online_page(pfn + i); | |
158 | if (!page) | |
159 | continue; | |
160 | return page; | |
161 | } | |
162 | return NULL; | |
a5d76b54 KH |
163 | } |
164 | ||
165 | /* | |
166 | * start_isolate_page_range() -- make page-allocation-type of range of pages | |
167 | * to be MIGRATE_ISOLATE. | |
168 | * @start_pfn: The lower PFN of the range to be isolated. | |
169 | * @end_pfn: The upper PFN of the range to be isolated. | |
0815f3d8 | 170 | * @migratetype: migrate type to set in error recovery. |
a5d76b54 KH |
171 | * |
172 | * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in | |
173 | * the range will never be allocated. Any free pages and pages freed in the | |
174 | * future will not be allocated again. | |
175 | * | |
176 | * start_pfn/end_pfn must be aligned to pageblock_order. | |
2c7452a0 MK |
177 | * Return 0 on success and -EBUSY if any part of range cannot be isolated. |
178 | * | |
179 | * There is no high level synchronization mechanism that prevents two threads | |
180 | * from trying to isolate overlapping ranges. If this happens, one thread | |
181 | * will notice pageblocks in the overlapping range already set to isolate. | |
182 | * This happens in set_migratetype_isolate, and set_migratetype_isolate | |
183 | * returns an error. We then clean up by restoring the migration type on | |
184 | * pageblocks we may have modified and return -EBUSY to caller. This | |
185 | * prevents two threads from simultaneously working on overlapping ranges. | |
a5d76b54 | 186 | */ |
0815f3d8 | 187 | int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
b023f468 | 188 | unsigned migratetype, bool skip_hwpoisoned_pages) |
a5d76b54 KH |
189 | { |
190 | unsigned long pfn; | |
191 | unsigned long undo_pfn; | |
192 | struct page *page; | |
193 | ||
fec174d6 NH |
194 | BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); |
195 | BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages)); | |
a5d76b54 KH |
196 | |
197 | for (pfn = start_pfn; | |
198 | pfn < end_pfn; | |
199 | pfn += pageblock_nr_pages) { | |
200 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
b023f468 | 201 | if (page && |
4da2ce25 | 202 | set_migratetype_isolate(page, migratetype, skip_hwpoisoned_pages)) { |
a5d76b54 KH |
203 | undo_pfn = pfn; |
204 | goto undo; | |
205 | } | |
206 | } | |
207 | return 0; | |
208 | undo: | |
209 | for (pfn = start_pfn; | |
dbc0e4ce | 210 | pfn < undo_pfn; |
2ce13640 MH |
211 | pfn += pageblock_nr_pages) { |
212 | struct page *page = pfn_to_online_page(pfn); | |
213 | if (!page) | |
214 | continue; | |
215 | unset_migratetype_isolate(page, migratetype); | |
216 | } | |
a5d76b54 KH |
217 | |
218 | return -EBUSY; | |
219 | } | |
220 | ||
221 | /* | |
222 | * Make isolated pages available again. | |
223 | */ | |
0815f3d8 MN |
224 | int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
225 | unsigned migratetype) | |
a5d76b54 KH |
226 | { |
227 | unsigned long pfn; | |
228 | struct page *page; | |
6f8d2b8a WX |
229 | |
230 | BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); | |
231 | BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages)); | |
232 | ||
a5d76b54 KH |
233 | for (pfn = start_pfn; |
234 | pfn < end_pfn; | |
235 | pfn += pageblock_nr_pages) { | |
236 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
bbf9ce97 | 237 | if (!page || !is_migrate_isolate_page(page)) |
a5d76b54 | 238 | continue; |
0815f3d8 | 239 | unset_migratetype_isolate(page, migratetype); |
a5d76b54 KH |
240 | } |
241 | return 0; | |
242 | } | |
243 | /* | |
244 | * Test all pages in the range is free(means isolated) or not. | |
245 | * all pages in [start_pfn...end_pfn) must be in the same zone. | |
246 | * zone->lock must be held before call this. | |
247 | * | |
ec3b6882 | 248 | * Returns the last tested pfn. |
a5d76b54 | 249 | */ |
fea85cff | 250 | static unsigned long |
b023f468 WC |
251 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, |
252 | bool skip_hwpoisoned_pages) | |
a5d76b54 KH |
253 | { |
254 | struct page *page; | |
255 | ||
256 | while (pfn < end_pfn) { | |
257 | if (!pfn_valid_within(pfn)) { | |
258 | pfn++; | |
259 | continue; | |
260 | } | |
261 | page = pfn_to_page(pfn); | |
aa016d14 | 262 | if (PageBuddy(page)) |
435b405c | 263 | /* |
aa016d14 VB |
264 | * If the page is on a free list, it has to be on |
265 | * the correct MIGRATE_ISOLATE freelist. There is no | |
266 | * simple way to verify that as VM_BUG_ON(), though. | |
435b405c | 267 | */ |
a5d76b54 | 268 | pfn += 1 << page_order(page); |
aa016d14 VB |
269 | else if (skip_hwpoisoned_pages && PageHWPoison(page)) |
270 | /* A HWPoisoned page cannot be also PageBuddy */ | |
b023f468 | 271 | pfn++; |
a5d76b54 KH |
272 | else |
273 | break; | |
274 | } | |
fea85cff JK |
275 | |
276 | return pfn; | |
a5d76b54 KH |
277 | } |
278 | ||
b9eb6319 | 279 | /* Caller should ensure that requested range is in a single zone */ |
b023f468 WC |
280 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn, |
281 | bool skip_hwpoisoned_pages) | |
a5d76b54 | 282 | { |
6c1b7f68 | 283 | unsigned long pfn, flags; |
a5d76b54 | 284 | struct page *page; |
6c1b7f68 | 285 | struct zone *zone; |
a5d76b54 | 286 | |
a5d76b54 | 287 | /* |
85dbe706 TC |
288 | * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages |
289 | * are not aligned to pageblock_nr_pages. | |
290 | * Then we just check migratetype first. | |
a5d76b54 KH |
291 | */ |
292 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
293 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
bbf9ce97 | 294 | if (page && !is_migrate_isolate_page(page)) |
a5d76b54 KH |
295 | break; |
296 | } | |
a70dcb96 GS |
297 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
298 | if ((pfn < end_pfn) || !page) | |
a5d76b54 | 299 | return -EBUSY; |
85dbe706 | 300 | /* Check all pages are free or marked as ISOLATED */ |
a70dcb96 | 301 | zone = page_zone(page); |
6c1b7f68 | 302 | spin_lock_irqsave(&zone->lock, flags); |
fea85cff | 303 | pfn = __test_page_isolated_in_pageblock(start_pfn, end_pfn, |
b023f468 | 304 | skip_hwpoisoned_pages); |
6c1b7f68 | 305 | spin_unlock_irqrestore(&zone->lock, flags); |
fea85cff | 306 | |
0f0848e5 JK |
307 | trace_test_pages_isolated(start_pfn, end_pfn, pfn); |
308 | ||
fea85cff | 309 | return pfn < end_pfn ? -EBUSY : 0; |
a5d76b54 | 310 | } |
723a0644 | 311 | |
666feb21 | 312 | struct page *alloc_migrate_target(struct page *page, unsigned long private) |
723a0644 | 313 | { |
8b913238 | 314 | return new_page_nodemask(page, numa_node_id(), &node_states[N_MEMORY]); |
723a0644 | 315 | } |