Commit | Line | Data |
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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 | ||
d381c547 | 18 | static int set_migratetype_isolate(struct page *page, int migratetype, int isol_flags) |
ee6f509c | 19 | { |
4a55c047 | 20 | struct page *unmovable = NULL; |
ee6f509c | 21 | struct zone *zone; |
3f9903b9 | 22 | unsigned long flags; |
ee6f509c MK |
23 | int ret = -EBUSY; |
24 | ||
25 | zone = page_zone(page); | |
26 | ||
27 | spin_lock_irqsave(&zone->lock, flags); | |
28 | ||
2c7452a0 MK |
29 | /* |
30 | * We assume the caller intended to SET migrate type to isolate. | |
31 | * If it is already set, then someone else must have raced and | |
32 | * set it before us. Return -EBUSY | |
33 | */ | |
34 | if (is_migrate_isolate_page(page)) | |
35 | goto out; | |
36 | ||
ee6f509c MK |
37 | /* |
38 | * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. | |
39 | * We just check MOVABLE pages. | |
40 | */ | |
4a55c047 QC |
41 | unmovable = has_unmovable_pages(zone, page, migratetype, isol_flags); |
42 | if (!unmovable) { | |
2139cbe6 | 43 | unsigned long nr_pages; |
4da2ce25 | 44 | int mt = get_pageblock_migratetype(page); |
2139cbe6 | 45 | |
a458431e | 46 | set_pageblock_migratetype(page, MIGRATE_ISOLATE); |
ad53f92e | 47 | zone->nr_isolate_pageblock++; |
02aa0cdd VB |
48 | nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE, |
49 | NULL); | |
2139cbe6 | 50 | |
4da2ce25 | 51 | __mod_zone_freepage_state(zone, -nr_pages, mt); |
3f9903b9 | 52 | ret = 0; |
ee6f509c MK |
53 | } |
54 | ||
3f9903b9 | 55 | out: |
ee6f509c | 56 | spin_unlock_irqrestore(&zone->lock, flags); |
3d680bdf | 57 | if (!ret) { |
ec25af84 | 58 | drain_all_pages(zone); |
3d680bdf QC |
59 | } else { |
60 | WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE); | |
61 | ||
62 | if ((isol_flags & REPORT_FAILURE) && unmovable) | |
63 | /* | |
64 | * printk() with zone->lock held will likely trigger a | |
65 | * lockdep splat, so defer it here. | |
66 | */ | |
67 | dump_page(unmovable, "unmovable page"); | |
68 | } | |
4a55c047 | 69 | |
ee6f509c MK |
70 | return ret; |
71 | } | |
72 | ||
c5b4e1b0 | 73 | static void unset_migratetype_isolate(struct page *page, unsigned migratetype) |
ee6f509c MK |
74 | { |
75 | struct zone *zone; | |
2139cbe6 | 76 | unsigned long flags, nr_pages; |
e3a2713c | 77 | bool isolated_page = false; |
3c605096 | 78 | unsigned int order; |
76741e77 | 79 | unsigned long pfn, buddy_pfn; |
3c605096 | 80 | struct page *buddy; |
2139cbe6 | 81 | |
ee6f509c MK |
82 | zone = page_zone(page); |
83 | spin_lock_irqsave(&zone->lock, flags); | |
bbf9ce97 | 84 | if (!is_migrate_isolate_page(page)) |
ee6f509c | 85 | goto out; |
3c605096 JK |
86 | |
87 | /* | |
88 | * Because freepage with more than pageblock_order on isolated | |
89 | * pageblock is restricted to merge due to freepage counting problem, | |
90 | * it is possible that there is free buddy page. | |
91 | * move_freepages_block() doesn't care of merge so we need other | |
92 | * approach in order to merge them. Isolation and free will make | |
93 | * these pages to be merged. | |
94 | */ | |
95 | if (PageBuddy(page)) { | |
96 | order = page_order(page); | |
97 | if (order >= pageblock_order) { | |
76741e77 VB |
98 | pfn = page_to_pfn(page); |
99 | buddy_pfn = __find_buddy_pfn(pfn, order); | |
100 | buddy = page + (buddy_pfn - pfn); | |
3c605096 | 101 | |
13ad59df | 102 | if (pfn_valid_within(buddy_pfn) && |
1ae7013d | 103 | !is_migrate_isolate_page(buddy)) { |
3c605096 | 104 | __isolate_free_page(page, order); |
e3a2713c | 105 | isolated_page = true; |
3c605096 JK |
106 | } |
107 | } | |
108 | } | |
109 | ||
110 | /* | |
111 | * If we isolate freepage with more than pageblock_order, there | |
112 | * should be no freepage in the range, so we could avoid costly | |
113 | * pageblock scanning for freepage moving. | |
114 | */ | |
115 | if (!isolated_page) { | |
02aa0cdd | 116 | nr_pages = move_freepages_block(zone, page, migratetype, NULL); |
3c605096 JK |
117 | __mod_zone_freepage_state(zone, nr_pages, migratetype); |
118 | } | |
a458431e | 119 | set_pageblock_migratetype(page, migratetype); |
624f58d8 AD |
120 | if (isolated_page) |
121 | __putback_isolated_page(page, order, migratetype); | |
ad53f92e | 122 | zone->nr_isolate_pageblock--; |
ee6f509c MK |
123 | out: |
124 | spin_unlock_irqrestore(&zone->lock, flags); | |
125 | } | |
126 | ||
a5d76b54 KH |
127 | static inline struct page * |
128 | __first_valid_page(unsigned long pfn, unsigned long nr_pages) | |
129 | { | |
130 | int i; | |
2ce13640 MH |
131 | |
132 | for (i = 0; i < nr_pages; i++) { | |
133 | struct page *page; | |
134 | ||
2ce13640 MH |
135 | page = pfn_to_online_page(pfn + i); |
136 | if (!page) | |
137 | continue; | |
138 | return page; | |
139 | } | |
140 | return NULL; | |
a5d76b54 KH |
141 | } |
142 | ||
9b7ea46a QC |
143 | /** |
144 | * start_isolate_page_range() - make page-allocation-type of range of pages to | |
145 | * be MIGRATE_ISOLATE. | |
146 | * @start_pfn: The lower PFN of the range to be isolated. | |
147 | * @end_pfn: The upper PFN of the range to be isolated. | |
148 | * start_pfn/end_pfn must be aligned to pageblock_order. | |
149 | * @migratetype: Migrate type to set in error recovery. | |
150 | * @flags: The following flags are allowed (they can be combined in | |
151 | * a bit mask) | |
756d25be DH |
152 | * MEMORY_OFFLINE - isolate to offline (!allocate) memory |
153 | * e.g., skip over PageHWPoison() pages | |
aa218795 | 154 | * and PageOffline() pages. |
9b7ea46a QC |
155 | * REPORT_FAILURE - report details about the failure to |
156 | * isolate the range | |
a5d76b54 KH |
157 | * |
158 | * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in | |
159 | * the range will never be allocated. Any free pages and pages freed in the | |
9b7ea46a QC |
160 | * future will not be allocated again. If specified range includes migrate types |
161 | * other than MOVABLE or CMA, this will fail with -EBUSY. For isolating all | |
162 | * pages in the range finally, the caller have to free all pages in the range. | |
163 | * test_page_isolated() can be used for test it. | |
2c7452a0 MK |
164 | * |
165 | * There is no high level synchronization mechanism that prevents two threads | |
9b7ea46a | 166 | * from trying to isolate overlapping ranges. If this happens, one thread |
2c7452a0 MK |
167 | * will notice pageblocks in the overlapping range already set to isolate. |
168 | * This happens in set_migratetype_isolate, and set_migratetype_isolate | |
9b7ea46a QC |
169 | * returns an error. We then clean up by restoring the migration type on |
170 | * pageblocks we may have modified and return -EBUSY to caller. This | |
2c7452a0 | 171 | * prevents two threads from simultaneously working on overlapping ranges. |
9b7ea46a QC |
172 | * |
173 | * Return: the number of isolated pageblocks on success and -EBUSY if any part | |
174 | * of range cannot be isolated. | |
a5d76b54 | 175 | */ |
0815f3d8 | 176 | int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
d381c547 | 177 | unsigned migratetype, int flags) |
a5d76b54 KH |
178 | { |
179 | unsigned long pfn; | |
180 | unsigned long undo_pfn; | |
181 | struct page *page; | |
9b7ea46a | 182 | int nr_isolate_pageblock = 0; |
a5d76b54 | 183 | |
fec174d6 NH |
184 | BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); |
185 | BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages)); | |
a5d76b54 KH |
186 | |
187 | for (pfn = start_pfn; | |
188 | pfn < end_pfn; | |
189 | pfn += pageblock_nr_pages) { | |
190 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
9b7ea46a QC |
191 | if (page) { |
192 | if (set_migratetype_isolate(page, migratetype, flags)) { | |
193 | undo_pfn = pfn; | |
194 | goto undo; | |
195 | } | |
196 | nr_isolate_pageblock++; | |
a5d76b54 KH |
197 | } |
198 | } | |
9b7ea46a | 199 | return nr_isolate_pageblock; |
a5d76b54 KH |
200 | undo: |
201 | for (pfn = start_pfn; | |
dbc0e4ce | 202 | pfn < undo_pfn; |
2ce13640 MH |
203 | pfn += pageblock_nr_pages) { |
204 | struct page *page = pfn_to_online_page(pfn); | |
205 | if (!page) | |
206 | continue; | |
207 | unset_migratetype_isolate(page, migratetype); | |
208 | } | |
a5d76b54 KH |
209 | |
210 | return -EBUSY; | |
211 | } | |
212 | ||
213 | /* | |
214 | * Make isolated pages available again. | |
215 | */ | |
1fcf0a56 | 216 | void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
0815f3d8 | 217 | unsigned migratetype) |
a5d76b54 KH |
218 | { |
219 | unsigned long pfn; | |
220 | struct page *page; | |
6f8d2b8a WX |
221 | |
222 | BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages)); | |
223 | BUG_ON(!IS_ALIGNED(end_pfn, pageblock_nr_pages)); | |
224 | ||
a5d76b54 KH |
225 | for (pfn = start_pfn; |
226 | pfn < end_pfn; | |
227 | pfn += pageblock_nr_pages) { | |
228 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
bbf9ce97 | 229 | if (!page || !is_migrate_isolate_page(page)) |
a5d76b54 | 230 | continue; |
0815f3d8 | 231 | unset_migratetype_isolate(page, migratetype); |
a5d76b54 | 232 | } |
a5d76b54 KH |
233 | } |
234 | /* | |
235 | * Test all pages in the range is free(means isolated) or not. | |
236 | * all pages in [start_pfn...end_pfn) must be in the same zone. | |
237 | * zone->lock must be held before call this. | |
238 | * | |
ec3b6882 | 239 | * Returns the last tested pfn. |
a5d76b54 | 240 | */ |
fea85cff | 241 | static unsigned long |
b023f468 | 242 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, |
756d25be | 243 | int flags) |
a5d76b54 KH |
244 | { |
245 | struct page *page; | |
246 | ||
247 | while (pfn < end_pfn) { | |
248 | if (!pfn_valid_within(pfn)) { | |
249 | pfn++; | |
250 | continue; | |
251 | } | |
252 | page = pfn_to_page(pfn); | |
aa016d14 | 253 | if (PageBuddy(page)) |
435b405c | 254 | /* |
aa016d14 VB |
255 | * If the page is on a free list, it has to be on |
256 | * the correct MIGRATE_ISOLATE freelist. There is no | |
257 | * simple way to verify that as VM_BUG_ON(), though. | |
435b405c | 258 | */ |
a5d76b54 | 259 | pfn += 1 << page_order(page); |
756d25be | 260 | else if ((flags & MEMORY_OFFLINE) && PageHWPoison(page)) |
aa016d14 | 261 | /* A HWPoisoned page cannot be also PageBuddy */ |
b023f468 | 262 | pfn++; |
aa218795 DH |
263 | else if ((flags & MEMORY_OFFLINE) && PageOffline(page) && |
264 | !page_count(page)) | |
265 | /* | |
266 | * The responsible driver agreed to skip PageOffline() | |
267 | * pages when offlining memory by dropping its | |
268 | * reference in MEM_GOING_OFFLINE. | |
269 | */ | |
270 | pfn++; | |
a5d76b54 KH |
271 | else |
272 | break; | |
273 | } | |
fea85cff JK |
274 | |
275 | return pfn; | |
a5d76b54 KH |
276 | } |
277 | ||
b9eb6319 | 278 | /* Caller should ensure that requested range is in a single zone */ |
b023f468 | 279 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn, |
756d25be | 280 | int isol_flags) |
a5d76b54 | 281 | { |
6c1b7f68 | 282 | unsigned long pfn, flags; |
a5d76b54 | 283 | struct page *page; |
6c1b7f68 | 284 | struct zone *zone; |
a5d76b54 | 285 | |
a5d76b54 | 286 | /* |
85dbe706 TC |
287 | * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages |
288 | * are not aligned to pageblock_nr_pages. | |
289 | * Then we just check migratetype first. | |
a5d76b54 KH |
290 | */ |
291 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
292 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
bbf9ce97 | 293 | if (page && !is_migrate_isolate_page(page)) |
a5d76b54 KH |
294 | break; |
295 | } | |
a70dcb96 GS |
296 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
297 | if ((pfn < end_pfn) || !page) | |
a5d76b54 | 298 | return -EBUSY; |
85dbe706 | 299 | /* Check all pages are free or marked as ISOLATED */ |
a70dcb96 | 300 | zone = page_zone(page); |
6c1b7f68 | 301 | spin_lock_irqsave(&zone->lock, flags); |
756d25be | 302 | pfn = __test_page_isolated_in_pageblock(start_pfn, end_pfn, isol_flags); |
6c1b7f68 | 303 | spin_unlock_irqrestore(&zone->lock, flags); |
fea85cff | 304 | |
0f0848e5 JK |
305 | trace_test_pages_isolated(start_pfn, end_pfn, pfn); |
306 | ||
fea85cff | 307 | return pfn < end_pfn ? -EBUSY : 0; |
a5d76b54 | 308 | } |