]>
Commit | Line | Data |
---|---|---|
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 | ||
1ae7013d HZ |
104 | if (pfn_valid_within(page_to_pfn(buddy)) && |
105 | !is_migrate_isolate_page(buddy)) { | |
3c605096 | 106 | __isolate_free_page(page, order); |
cfa86943 | 107 | kernel_map_pages(page, (1 << order), 1); |
3c605096 JK |
108 | set_page_refcounted(page); |
109 | isolated_page = page; | |
110 | } | |
111 | } | |
112 | } | |
113 | ||
114 | /* | |
115 | * If we isolate freepage with more than pageblock_order, there | |
116 | * should be no freepage in the range, so we could avoid costly | |
117 | * pageblock scanning for freepage moving. | |
118 | */ | |
119 | if (!isolated_page) { | |
120 | nr_pages = move_freepages_block(zone, page, migratetype); | |
121 | __mod_zone_freepage_state(zone, nr_pages, migratetype); | |
122 | } | |
a458431e | 123 | set_pageblock_migratetype(page, migratetype); |
ad53f92e | 124 | zone->nr_isolate_pageblock--; |
ee6f509c MK |
125 | out: |
126 | spin_unlock_irqrestore(&zone->lock, flags); | |
3c605096 JK |
127 | if (isolated_page) |
128 | __free_pages(isolated_page, order); | |
ee6f509c MK |
129 | } |
130 | ||
a5d76b54 KH |
131 | static inline struct page * |
132 | __first_valid_page(unsigned long pfn, unsigned long nr_pages) | |
133 | { | |
134 | int i; | |
135 | for (i = 0; i < nr_pages; i++) | |
136 | if (pfn_valid_within(pfn + i)) | |
137 | break; | |
138 | if (unlikely(i == nr_pages)) | |
139 | return NULL; | |
140 | return pfn_to_page(pfn + i); | |
141 | } | |
142 | ||
143 | /* | |
144 | * start_isolate_page_range() -- make page-allocation-type of range of pages | |
145 | * to 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. | |
0815f3d8 | 148 | * @migratetype: migrate type to set in error recovery. |
a5d76b54 KH |
149 | * |
150 | * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in | |
151 | * the range will never be allocated. Any free pages and pages freed in the | |
152 | * future will not be allocated again. | |
153 | * | |
154 | * start_pfn/end_pfn must be aligned to pageblock_order. | |
155 | * Returns 0 on success and -EBUSY if any part of range cannot be isolated. | |
156 | */ | |
0815f3d8 | 157 | int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
b023f468 | 158 | unsigned migratetype, bool skip_hwpoisoned_pages) |
a5d76b54 KH |
159 | { |
160 | unsigned long pfn; | |
161 | unsigned long undo_pfn; | |
162 | struct page *page; | |
163 | ||
164 | BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); | |
165 | BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); | |
166 | ||
167 | for (pfn = start_pfn; | |
168 | pfn < end_pfn; | |
169 | pfn += pageblock_nr_pages) { | |
170 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
b023f468 WC |
171 | if (page && |
172 | set_migratetype_isolate(page, skip_hwpoisoned_pages)) { | |
a5d76b54 KH |
173 | undo_pfn = pfn; |
174 | goto undo; | |
175 | } | |
176 | } | |
177 | return 0; | |
178 | undo: | |
179 | for (pfn = start_pfn; | |
dbc0e4ce | 180 | pfn < undo_pfn; |
a5d76b54 | 181 | pfn += pageblock_nr_pages) |
0815f3d8 | 182 | unset_migratetype_isolate(pfn_to_page(pfn), migratetype); |
a5d76b54 KH |
183 | |
184 | return -EBUSY; | |
185 | } | |
186 | ||
187 | /* | |
188 | * Make isolated pages available again. | |
189 | */ | |
0815f3d8 MN |
190 | int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
191 | unsigned migratetype) | |
a5d76b54 KH |
192 | { |
193 | unsigned long pfn; | |
194 | struct page *page; | |
195 | BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); | |
196 | BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); | |
197 | for (pfn = start_pfn; | |
198 | pfn < end_pfn; | |
199 | pfn += pageblock_nr_pages) { | |
200 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 201 | if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 | 202 | continue; |
0815f3d8 | 203 | unset_migratetype_isolate(page, migratetype); |
a5d76b54 KH |
204 | } |
205 | return 0; | |
206 | } | |
207 | /* | |
208 | * Test all pages in the range is free(means isolated) or not. | |
209 | * all pages in [start_pfn...end_pfn) must be in the same zone. | |
210 | * zone->lock must be held before call this. | |
211 | * | |
0815f3d8 | 212 | * Returns 1 if all pages in the range are isolated. |
a5d76b54 KH |
213 | */ |
214 | static int | |
b023f468 WC |
215 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn, |
216 | bool skip_hwpoisoned_pages) | |
a5d76b54 KH |
217 | { |
218 | struct page *page; | |
219 | ||
220 | while (pfn < end_pfn) { | |
221 | if (!pfn_valid_within(pfn)) { | |
222 | pfn++; | |
223 | continue; | |
224 | } | |
225 | page = pfn_to_page(pfn); | |
41d575ad | 226 | if (PageBuddy(page)) { |
435b405c MK |
227 | /* |
228 | * If race between isolatation and allocation happens, | |
229 | * some free pages could be in MIGRATE_MOVABLE list | |
230 | * although pageblock's migratation type of the page | |
231 | * is MIGRATE_ISOLATE. Catch it and move the page into | |
232 | * MIGRATE_ISOLATE list. | |
233 | */ | |
234 | if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) { | |
235 | struct page *end_page; | |
236 | ||
237 | end_page = page + (1 << page_order(page)) - 1; | |
238 | move_freepages(page_zone(page), page, end_page, | |
239 | MIGRATE_ISOLATE); | |
240 | } | |
a5d76b54 | 241 | pfn += 1 << page_order(page); |
41d575ad | 242 | } |
a5d76b54 | 243 | else if (page_count(page) == 0 && |
b12c4ad1 | 244 | get_freepage_migratetype(page) == MIGRATE_ISOLATE) |
a5d76b54 | 245 | pfn += 1; |
b023f468 WC |
246 | else if (skip_hwpoisoned_pages && PageHWPoison(page)) { |
247 | /* | |
248 | * The HWPoisoned page may be not in buddy | |
249 | * system, and page_count() is not 0. | |
250 | */ | |
251 | pfn++; | |
252 | continue; | |
253 | } | |
a5d76b54 KH |
254 | else |
255 | break; | |
256 | } | |
257 | if (pfn < end_pfn) | |
258 | return 0; | |
259 | return 1; | |
260 | } | |
261 | ||
b023f468 WC |
262 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn, |
263 | bool skip_hwpoisoned_pages) | |
a5d76b54 | 264 | { |
6c1b7f68 | 265 | unsigned long pfn, flags; |
a5d76b54 | 266 | struct page *page; |
6c1b7f68 GS |
267 | struct zone *zone; |
268 | int ret; | |
a5d76b54 | 269 | |
a5d76b54 | 270 | /* |
85dbe706 TC |
271 | * Note: pageblock_nr_pages != MAX_ORDER. Then, chunks of free pages |
272 | * are not aligned to pageblock_nr_pages. | |
273 | * Then we just check migratetype first. | |
a5d76b54 KH |
274 | */ |
275 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
276 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 277 | if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 KH |
278 | break; |
279 | } | |
a70dcb96 GS |
280 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
281 | if ((pfn < end_pfn) || !page) | |
a5d76b54 | 282 | return -EBUSY; |
85dbe706 | 283 | /* Check all pages are free or marked as ISOLATED */ |
a70dcb96 | 284 | zone = page_zone(page); |
6c1b7f68 | 285 | spin_lock_irqsave(&zone->lock, flags); |
b023f468 WC |
286 | ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn, |
287 | skip_hwpoisoned_pages); | |
6c1b7f68 GS |
288 | spin_unlock_irqrestore(&zone->lock, flags); |
289 | return ret ? 0 : -EBUSY; | |
a5d76b54 | 290 | } |
723a0644 MK |
291 | |
292 | struct page *alloc_migrate_target(struct page *page, unsigned long private, | |
293 | int **resultp) | |
294 | { | |
295 | gfp_t gfp_mask = GFP_USER | __GFP_MOVABLE; | |
296 | ||
c8721bbb NH |
297 | /* |
298 | * TODO: allocate a destination hugepage from a nearest neighbor node, | |
299 | * accordance with memory policy of the user process if possible. For | |
300 | * now as a simple work-around, we use the next node for destination. | |
301 | */ | |
302 | if (PageHuge(page)) { | |
303 | nodemask_t src = nodemask_of_node(page_to_nid(page)); | |
304 | nodemask_t dst; | |
305 | nodes_complement(dst, src); | |
306 | return alloc_huge_page_node(page_hstate(compound_head(page)), | |
307 | next_node(page_to_nid(page), dst)); | |
308 | } | |
309 | ||
723a0644 MK |
310 | if (PageHighMem(page)) |
311 | gfp_mask |= __GFP_HIGHMEM; | |
312 | ||
313 | return alloc_page(gfp_mask); | |
314 | } |