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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> |
a5d76b54 KH |
9 | #include "internal.h" |
10 | ||
ee6f509c MK |
11 | int set_migratetype_isolate(struct page *page) |
12 | { | |
13 | struct zone *zone; | |
14 | unsigned long flags, pfn; | |
15 | struct memory_isolate_notify arg; | |
16 | int notifier_ret; | |
17 | int ret = -EBUSY; | |
18 | ||
19 | zone = page_zone(page); | |
20 | ||
21 | spin_lock_irqsave(&zone->lock, flags); | |
22 | ||
23 | pfn = page_to_pfn(page); | |
24 | arg.start_pfn = pfn; | |
25 | arg.nr_pages = pageblock_nr_pages; | |
26 | arg.pages_found = 0; | |
27 | ||
28 | /* | |
29 | * It may be possible to isolate a pageblock even if the | |
30 | * migratetype is not MIGRATE_MOVABLE. The memory isolation | |
31 | * notifier chain is used by balloon drivers to return the | |
32 | * number of pages in a range that are held by the balloon | |
33 | * driver to shrink memory. If all the pages are accounted for | |
34 | * by balloons, are free, or on the LRU, isolation can continue. | |
35 | * Later, for example, when memory hotplug notifier runs, these | |
36 | * pages reported as "can be isolated" should be isolated(freed) | |
37 | * by the balloon driver through the memory notifier chain. | |
38 | */ | |
39 | notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg); | |
40 | notifier_ret = notifier_to_errno(notifier_ret); | |
41 | if (notifier_ret) | |
42 | goto out; | |
43 | /* | |
44 | * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. | |
45 | * We just check MOVABLE pages. | |
46 | */ | |
47 | if (!has_unmovable_pages(zone, page, arg.pages_found)) | |
48 | ret = 0; | |
49 | ||
50 | /* | |
51 | * immobile means "not-on-lru" paes. If immobile is larger than | |
52 | * removable-by-driver pages reported by notifier, we'll fail. | |
53 | */ | |
54 | ||
55 | out: | |
56 | if (!ret) { | |
57 | set_pageblock_migratetype(page, MIGRATE_ISOLATE); | |
58 | move_freepages_block(zone, page, MIGRATE_ISOLATE); | |
59 | } | |
60 | ||
61 | spin_unlock_irqrestore(&zone->lock, flags); | |
62 | if (!ret) | |
63 | drain_all_pages(); | |
64 | return ret; | |
65 | } | |
66 | ||
67 | void unset_migratetype_isolate(struct page *page, unsigned migratetype) | |
68 | { | |
69 | struct zone *zone; | |
70 | unsigned long flags; | |
71 | zone = page_zone(page); | |
72 | spin_lock_irqsave(&zone->lock, flags); | |
73 | if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) | |
74 | goto out; | |
75 | set_pageblock_migratetype(page, migratetype); | |
76 | move_freepages_block(zone, page, migratetype); | |
77 | out: | |
78 | spin_unlock_irqrestore(&zone->lock, flags); | |
79 | } | |
80 | ||
a5d76b54 KH |
81 | static inline struct page * |
82 | __first_valid_page(unsigned long pfn, unsigned long nr_pages) | |
83 | { | |
84 | int i; | |
85 | for (i = 0; i < nr_pages; i++) | |
86 | if (pfn_valid_within(pfn + i)) | |
87 | break; | |
88 | if (unlikely(i == nr_pages)) | |
89 | return NULL; | |
90 | return pfn_to_page(pfn + i); | |
91 | } | |
92 | ||
93 | /* | |
94 | * start_isolate_page_range() -- make page-allocation-type of range of pages | |
95 | * to be MIGRATE_ISOLATE. | |
96 | * @start_pfn: The lower PFN of the range to be isolated. | |
97 | * @end_pfn: The upper PFN of the range to be isolated. | |
0815f3d8 | 98 | * @migratetype: migrate type to set in error recovery. |
a5d76b54 KH |
99 | * |
100 | * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in | |
101 | * the range will never be allocated. Any free pages and pages freed in the | |
102 | * future will not be allocated again. | |
103 | * | |
104 | * start_pfn/end_pfn must be aligned to pageblock_order. | |
105 | * Returns 0 on success and -EBUSY if any part of range cannot be isolated. | |
106 | */ | |
0815f3d8 MN |
107 | int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
108 | unsigned migratetype) | |
a5d76b54 KH |
109 | { |
110 | unsigned long pfn; | |
111 | unsigned long undo_pfn; | |
112 | struct page *page; | |
113 | ||
114 | BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); | |
115 | BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); | |
116 | ||
117 | for (pfn = start_pfn; | |
118 | pfn < end_pfn; | |
119 | pfn += pageblock_nr_pages) { | |
120 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
121 | if (page && set_migratetype_isolate(page)) { | |
122 | undo_pfn = pfn; | |
123 | goto undo; | |
124 | } | |
125 | } | |
126 | return 0; | |
127 | undo: | |
128 | for (pfn = start_pfn; | |
dbc0e4ce | 129 | pfn < undo_pfn; |
a5d76b54 | 130 | pfn += pageblock_nr_pages) |
0815f3d8 | 131 | unset_migratetype_isolate(pfn_to_page(pfn), migratetype); |
a5d76b54 KH |
132 | |
133 | return -EBUSY; | |
134 | } | |
135 | ||
136 | /* | |
137 | * Make isolated pages available again. | |
138 | */ | |
0815f3d8 MN |
139 | int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, |
140 | unsigned migratetype) | |
a5d76b54 KH |
141 | { |
142 | unsigned long pfn; | |
143 | struct page *page; | |
144 | BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); | |
145 | BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); | |
146 | for (pfn = start_pfn; | |
147 | pfn < end_pfn; | |
148 | pfn += pageblock_nr_pages) { | |
149 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 150 | if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 | 151 | continue; |
0815f3d8 | 152 | unset_migratetype_isolate(page, migratetype); |
a5d76b54 KH |
153 | } |
154 | return 0; | |
155 | } | |
156 | /* | |
157 | * Test all pages in the range is free(means isolated) or not. | |
158 | * all pages in [start_pfn...end_pfn) must be in the same zone. | |
159 | * zone->lock must be held before call this. | |
160 | * | |
0815f3d8 | 161 | * Returns 1 if all pages in the range are isolated. |
a5d76b54 KH |
162 | */ |
163 | static int | |
164 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn) | |
165 | { | |
166 | struct page *page; | |
167 | ||
168 | while (pfn < end_pfn) { | |
169 | if (!pfn_valid_within(pfn)) { | |
170 | pfn++; | |
171 | continue; | |
172 | } | |
173 | page = pfn_to_page(pfn); | |
174 | if (PageBuddy(page)) | |
175 | pfn += 1 << page_order(page); | |
176 | else if (page_count(page) == 0 && | |
177 | page_private(page) == MIGRATE_ISOLATE) | |
178 | pfn += 1; | |
179 | else | |
180 | break; | |
181 | } | |
182 | if (pfn < end_pfn) | |
183 | return 0; | |
184 | return 1; | |
185 | } | |
186 | ||
187 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) | |
188 | { | |
6c1b7f68 | 189 | unsigned long pfn, flags; |
a5d76b54 | 190 | struct page *page; |
6c1b7f68 GS |
191 | struct zone *zone; |
192 | int ret; | |
a5d76b54 | 193 | |
a5d76b54 KH |
194 | /* |
195 | * Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page | |
196 | * is not aligned to pageblock_nr_pages. | |
197 | * Then we just check pagetype fist. | |
198 | */ | |
199 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
200 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 201 | if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 KH |
202 | break; |
203 | } | |
a70dcb96 GS |
204 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
205 | if ((pfn < end_pfn) || !page) | |
a5d76b54 KH |
206 | return -EBUSY; |
207 | /* Check all pages are free or Marked as ISOLATED */ | |
a70dcb96 | 208 | zone = page_zone(page); |
6c1b7f68 GS |
209 | spin_lock_irqsave(&zone->lock, flags); |
210 | ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn); | |
211 | spin_unlock_irqrestore(&zone->lock, flags); | |
212 | return ret ? 0 : -EBUSY; | |
a5d76b54 | 213 | } |