2 * linux/mm/page_isolation.c
6 #include <linux/page-isolation.h>
7 #include <linux/pageblock-flags.h>
10 static inline struct page *
11 __first_valid_page(unsigned long pfn, unsigned long nr_pages)
14 for (i = 0; i < nr_pages; i++)
15 if (pfn_valid_within(pfn + i))
17 if (unlikely(i == nr_pages))
19 return pfn_to_page(pfn + i);
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.
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.
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.
36 start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
39 unsigned long undo_pfn;
42 BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
43 BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
47 pfn += pageblock_nr_pages) {
48 page = __first_valid_page(pfn, pageblock_nr_pages);
49 if (page && set_migratetype_isolate(page)) {
58 pfn += pageblock_nr_pages)
59 unset_migratetype_isolate(pfn_to_page(pfn));
65 * Make isolated pages available again.
68 undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
72 BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
73 BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
76 pfn += pageblock_nr_pages) {
77 page = __first_valid_page(pfn, pageblock_nr_pages);
78 if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
80 unset_migratetype_isolate(page);
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.
89 * Returns 0 if all pages in the range is isolated.
92 __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn)
96 while (pfn < end_pfn) {
97 if (!pfn_valid_within(pfn)) {
101 page = pfn_to_page(pfn);
103 pfn += 1 << page_order(page);
104 else if (page_count(page) == 0 &&
105 page_private(page) == MIGRATE_ISOLATE)
115 int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
117 unsigned long pfn, flags;
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.
128 for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
129 page = __first_valid_page(pfn, pageblock_nr_pages);
130 if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
133 page = __first_valid_page(start_pfn, end_pfn - start_pfn);
134 if ((pfn < end_pfn) || !page)
136 /* Check all pages are free or Marked as ISOLATED */
137 zone = page_zone(page);
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;