Commit | Line | Data |
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a5d76b54 KH |
1 | /* |
2 | * linux/mm/page_isolation.c | |
3 | */ | |
4 | ||
a5d76b54 KH |
5 | #include <linux/mm.h> |
6 | #include <linux/page-isolation.h> | |
7 | #include <linux/pageblock-flags.h> | |
ee6f509c | 8 | #include <linux/memory.h> |
c8721bbb | 9 | #include <linux/hugetlb.h> |
a5d76b54 KH |
10 | #include "internal.h" |
11 | ||
b023f468 | 12 | int set_migratetype_isolate(struct page *page, bool skip_hwpoisoned_pages) |
ee6f509c MK |
13 | { |
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 | */ | |
b023f468 WC |
48 | if (!has_unmovable_pages(zone, page, arg.pages_found, |
49 | skip_hwpoisoned_pages)) | |
ee6f509c MK |
50 | 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 | ||
57 | out: | |
58 | if (!ret) { | |
2139cbe6 | 59 | unsigned long nr_pages; |
d1ce749a | 60 | int migratetype = get_pageblock_migratetype(page); |
2139cbe6 | 61 | |
a458431e | 62 | set_pageblock_migratetype(page, MIGRATE_ISOLATE); |
ad53f92e | 63 | zone->nr_isolate_pageblock++; |
2139cbe6 BZ |
64 | nr_pages = move_freepages_block(zone, page, MIGRATE_ISOLATE); |
65 | ||
d1ce749a | 66 | __mod_zone_freepage_state(zone, -nr_pages, migratetype); |
ee6f509c MK |
67 | } |
68 | ||
69 | spin_unlock_irqrestore(&zone->lock, flags); | |
70 | if (!ret) | |
ec25af84 | 71 | drain_all_pages(zone); |
ee6f509c MK |
72 | return ret; |
73 | } | |
74 | ||
75 | void unset_migratetype_isolate(struct page *page, unsigned migratetype) | |
76 | { | |
77 | struct zone *zone; | |
2139cbe6 | 78 | unsigned long flags, nr_pages; |
3c605096 JK |
79 | struct page *isolated_page = NULL; |
80 | unsigned int order; | |
81 | unsigned long page_idx, buddy_idx; | |
82 | struct page *buddy; | |
2139cbe6 | 83 | |
ee6f509c MK |
84 | zone = page_zone(page); |
85 | spin_lock_irqsave(&zone->lock, flags); | |
86 | if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) | |
87 | goto out; | |
3c605096 JK |
88 | |
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); | |
cfa86943 | 106 | kernel_map_pages(page, (1 << order), 1); |
3c605096 JK |
107 | 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 | } | |
a458431e | 122 | set_pageblock_migratetype(page, migratetype); |
ad53f92e | 123 | zone->nr_isolate_pageblock--; |
ee6f509c MK |
124 | out: |
125 | spin_unlock_irqrestore(&zone->lock, flags); | |
3c605096 JK |
126 | if (isolated_page) |
127 | __free_pages(isolated_page, order); | |
ee6f509c MK |
128 | } |
129 | ||
a5d76b54 KH |
130 | static 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. | |
0815f3d8 | 147 | * @migratetype: migrate type to set in error recovery. |
a5d76b54 KH |
148 | * |
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 | */ | |
0815f3d8 | 156 | int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
b023f468 | 157 | unsigned migratetype, bool skip_hwpoisoned_pages) |
a5d76b54 KH |
158 | { |
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); | |
b023f468 WC |
170 | if (page && |
171 | set_migratetype_isolate(page, skip_hwpoisoned_pages)) { | |
a5d76b54 KH |
172 | undo_pfn = pfn; |
173 | goto undo; | |
174 | } | |
175 | } | |
176 | return 0; | |
177 | undo: | |
178 | for (pfn = start_pfn; | |
dbc0e4ce | 179 | pfn < undo_pfn; |
a5d76b54 | 180 | pfn += pageblock_nr_pages) |
0815f3d8 | 181 | unset_migratetype_isolate(pfn_to_page(pfn), migratetype); |
a5d76b54 KH |
182 | |
183 | return -EBUSY; | |
184 | } | |
185 | ||
186 | /* | |
187 | * Make isolated pages available again. | |
188 | */ | |
0815f3d8 MN |
189 | int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
190 | unsigned migratetype) | |
a5d76b54 KH |
191 | { |
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); | |
dbc0e4ce | 200 | if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 | 201 | continue; |
0815f3d8 | 202 | unset_migratetype_isolate(page, migratetype); |
a5d76b54 KH |
203 | } |
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 | * | |
0815f3d8 | 211 | * Returns 1 if all pages in the range are isolated. |
a5d76b54 KH |
212 | */ |
213 | static int | |
b023f468 WC |
214 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, |
215 | bool skip_hwpoisoned_pages) | |
a5d76b54 KH |
216 | { |
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); | |
41d575ad | 225 | if (PageBuddy(page)) { |
435b405c MK |
226 | /* |
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 | } | |
a5d76b54 | 240 | pfn += 1 << page_order(page); |
41d575ad | 241 | } |
a5d76b54 | 242 | else if (page_count(page) == 0 && |
b12c4ad1 | 243 | get_freepage_migratetype(page) == MIGRATE_ISOLATE) |
a5d76b54 | 244 | pfn += 1; |
b023f468 WC |
245 | 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 | } | |
a5d76b54 KH |
253 | else |
254 | break; | |
255 | } | |
256 | if (pfn < end_pfn) | |
257 | return 0; | |
258 | return 1; | |
259 | } | |
260 | ||
b023f468 WC |
261 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn, |
262 | bool skip_hwpoisoned_pages) | |
a5d76b54 | 263 | { |
6c1b7f68 | 264 | unsigned long pfn, flags; |
a5d76b54 | 265 | struct page *page; |
6c1b7f68 GS |
266 | struct zone *zone; |
267 | int ret; | |
a5d76b54 | 268 | |
a5d76b54 | 269 | /* |
85dbe706 TC |
270 | * 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. | |
a5d76b54 KH |
273 | */ |
274 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
275 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 276 | if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 KH |
277 | break; |
278 | } | |
a70dcb96 GS |
279 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
280 | if ((pfn < end_pfn) || !page) | |
a5d76b54 | 281 | return -EBUSY; |
85dbe706 | 282 | /* Check all pages are free or marked as ISOLATED */ |
a70dcb96 | 283 | zone = page_zone(page); |
6c1b7f68 | 284 | spin_lock_irqsave(&zone->lock, flags); |
b023f468 WC |
285 | ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn, |
286 | skip_hwpoisoned_pages); | |
6c1b7f68 GS |
287 | spin_unlock_irqrestore(&zone->lock, flags); |
288 | return ret ? 0 : -EBUSY; | |
a5d76b54 | 289 | } |
723a0644 MK |
290 | |
291 | struct page *alloc_migrate_target(struct page *page, unsigned long private, | |
292 | int **resultp) | |
293 | { | |
294 | gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE; | |
295 | ||
c8721bbb NH |
296 | /* |
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 | ||
723a0644 MK |
309 | if (PageHighMem(page)) |
310 | gfp_mask |= __GFP_HIGHMEM; | |
311 | ||
312 | return alloc_page(gfp_mask); | |
313 | } |