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> | |
8 | #include "internal.h" | |
9 | ||
10 | static inline struct page * | |
11 | __first_valid_page(unsigned long pfn, unsigned long nr_pages) | |
12 | { | |
13 | int i; | |
14 | for (i = 0; i < nr_pages; i++) | |
15 | if (pfn_valid_within(pfn + i)) | |
16 | break; | |
17 | if (unlikely(i == nr_pages)) | |
18 | return NULL; | |
19 | return pfn_to_page(pfn + i); | |
20 | } | |
21 | ||
22 | /* | |
23 | * start_isolate_page_range() -- make page-allocation-type of range of pages | |
24 | * to be MIGRATE_ISOLATE. | |
25 | * @start_pfn: The lower PFN of the range to be isolated. | |
26 | * @end_pfn: The upper PFN of the range to be isolated. | |
27 | * | |
28 | * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in | |
29 | * the range will never be allocated. Any free pages and pages freed in the | |
30 | * future will not be allocated again. | |
31 | * | |
32 | * start_pfn/end_pfn must be aligned to pageblock_order. | |
33 | * Returns 0 on success and -EBUSY if any part of range cannot be isolated. | |
34 | */ | |
35 | int | |
36 | start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn) | |
37 | { | |
38 | unsigned long pfn; | |
39 | unsigned long undo_pfn; | |
40 | struct page *page; | |
41 | ||
42 | BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); | |
43 | BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); | |
44 | ||
45 | for (pfn = start_pfn; | |
46 | pfn < end_pfn; | |
47 | pfn += pageblock_nr_pages) { | |
48 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
49 | if (page && set_migratetype_isolate(page)) { | |
50 | undo_pfn = pfn; | |
51 | goto undo; | |
52 | } | |
53 | } | |
54 | return 0; | |
55 | undo: | |
56 | for (pfn = start_pfn; | |
dbc0e4ce | 57 | pfn < undo_pfn; |
a5d76b54 KH |
58 | pfn += pageblock_nr_pages) |
59 | unset_migratetype_isolate(pfn_to_page(pfn)); | |
60 | ||
61 | return -EBUSY; | |
62 | } | |
63 | ||
64 | /* | |
65 | * Make isolated pages available again. | |
66 | */ | |
67 | int | |
68 | undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn) | |
69 | { | |
70 | unsigned long pfn; | |
71 | struct page *page; | |
72 | BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); | |
73 | BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); | |
74 | for (pfn = start_pfn; | |
75 | pfn < end_pfn; | |
76 | pfn += pageblock_nr_pages) { | |
77 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 78 | if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 KH |
79 | continue; |
80 | unset_migratetype_isolate(page); | |
81 | } | |
82 | return 0; | |
83 | } | |
84 | /* | |
85 | * Test all pages in the range is free(means isolated) or not. | |
86 | * all pages in [start_pfn...end_pfn) must be in the same zone. | |
87 | * zone->lock must be held before call this. | |
88 | * | |
89 | * Returns 0 if all pages in the range is isolated. | |
90 | */ | |
91 | static int | |
92 | __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn) | |
93 | { | |
94 | struct page *page; | |
95 | ||
96 | while (pfn < end_pfn) { | |
97 | if (!pfn_valid_within(pfn)) { | |
98 | pfn++; | |
99 | continue; | |
100 | } | |
101 | page = pfn_to_page(pfn); | |
102 | if (PageBuddy(page)) | |
103 | pfn += 1 << page_order(page); | |
104 | else if (page_count(page) == 0 && | |
105 | page_private(page) == MIGRATE_ISOLATE) | |
106 | pfn += 1; | |
107 | else | |
108 | break; | |
109 | } | |
110 | if (pfn < end_pfn) | |
111 | return 0; | |
112 | return 1; | |
113 | } | |
114 | ||
115 | int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) | |
116 | { | |
6c1b7f68 | 117 | unsigned long pfn, flags; |
a5d76b54 | 118 | struct page *page; |
6c1b7f68 GS |
119 | struct zone *zone; |
120 | int ret; | |
a5d76b54 KH |
121 | |
122 | pfn = start_pfn; | |
123 | /* | |
124 | * Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page | |
125 | * is not aligned to pageblock_nr_pages. | |
126 | * Then we just check pagetype fist. | |
127 | */ | |
128 | for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { | |
129 | page = __first_valid_page(pfn, pageblock_nr_pages); | |
dbc0e4ce | 130 | if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
a5d76b54 KH |
131 | break; |
132 | } | |
a70dcb96 GS |
133 | page = __first_valid_page(start_pfn, end_pfn - start_pfn); |
134 | if ((pfn < end_pfn) || !page) | |
a5d76b54 KH |
135 | return -EBUSY; |
136 | /* Check all pages are free or Marked as ISOLATED */ | |
a70dcb96 | 137 | zone = page_zone(page); |
6c1b7f68 GS |
138 | spin_lock_irqsave(&zone->lock, flags); |
139 | ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn); | |
140 | spin_unlock_irqrestore(&zone->lock, flags); | |
141 | return ret ? 0 : -EBUSY; | |
a5d76b54 | 142 | } |