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mm/page_isolation.c
6.24 KB
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/* * linux/mm/page_isolation.c */ |
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#include <linux/mm.h> #include <linux/page-isolation.h> #include <linux/pageblock-flags.h> |
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#include <linux/memory.h> |
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#include "internal.h" |
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/* called while holding zone->lock */ static void set_pageblock_isolate(struct page *page) { if (get_pageblock_migratetype(page) == MIGRATE_ISOLATE) return; set_pageblock_migratetype(page, MIGRATE_ISOLATE); page_zone(page)->nr_pageblock_isolate++; } /* called while holding zone->lock */ static void restore_pageblock_isolate(struct page *page, int migratetype) { struct zone *zone = page_zone(page); if (WARN_ON(get_pageblock_migratetype(page) != MIGRATE_ISOLATE)) return; BUG_ON(zone->nr_pageblock_isolate <= 0); set_pageblock_migratetype(page, migratetype); zone->nr_pageblock_isolate--; } |
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int set_migratetype_isolate(struct page *page) { struct zone *zone; unsigned long flags, pfn; struct memory_isolate_notify arg; int notifier_ret; int ret = -EBUSY; zone = page_zone(page); spin_lock_irqsave(&zone->lock, flags); pfn = page_to_pfn(page); arg.start_pfn = pfn; arg.nr_pages = pageblock_nr_pages; arg.pages_found = 0; /* * It may be possible to isolate a pageblock even if the * migratetype is not MIGRATE_MOVABLE. The memory isolation * notifier chain is used by balloon drivers to return the * number of pages in a range that are held by the balloon * driver to shrink memory. If all the pages are accounted for * by balloons, are free, or on the LRU, isolation can continue. * Later, for example, when memory hotplug notifier runs, these * pages reported as "can be isolated" should be isolated(freed) * by the balloon driver through the memory notifier chain. */ notifier_ret = memory_isolate_notify(MEM_ISOLATE_COUNT, &arg); notifier_ret = notifier_to_errno(notifier_ret); if (notifier_ret) goto out; /* * FIXME: Now, memory hotplug doesn't call shrink_slab() by itself. * We just check MOVABLE pages. */ if (!has_unmovable_pages(zone, page, arg.pages_found)) ret = 0; /* * immobile means "not-on-lru" paes. If immobile is larger than * removable-by-driver pages reported by notifier, we'll fail. */ out: if (!ret) { |
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set_pageblock_isolate(page); |
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move_freepages_block(zone, page, MIGRATE_ISOLATE); } spin_unlock_irqrestore(&zone->lock, flags); if (!ret) drain_all_pages(); return ret; } void unset_migratetype_isolate(struct page *page, unsigned migratetype) { struct zone *zone; unsigned long flags; zone = page_zone(page); spin_lock_irqsave(&zone->lock, flags); if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) goto out; |
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move_freepages_block(zone, page, migratetype); |
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restore_pageblock_isolate(page, migratetype); |
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out: spin_unlock_irqrestore(&zone->lock, flags); } |
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static inline struct page * __first_valid_page(unsigned long pfn, unsigned long nr_pages) { int i; for (i = 0; i < nr_pages; i++) if (pfn_valid_within(pfn + i)) break; if (unlikely(i == nr_pages)) return NULL; return pfn_to_page(pfn + i); } /* * start_isolate_page_range() -- make page-allocation-type of range of pages * to be MIGRATE_ISOLATE. * @start_pfn: The lower PFN of the range to be isolated. * @end_pfn: The upper PFN of the range to be isolated. |
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* @migratetype: migrate type to set in error recovery. |
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* * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in * the range will never be allocated. Any free pages and pages freed in the * future will not be allocated again. * * start_pfn/end_pfn must be aligned to pageblock_order. * Returns 0 on success and -EBUSY if any part of range cannot be isolated. */ |
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int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, unsigned migratetype) |
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{ unsigned long pfn; unsigned long undo_pfn; struct page *page; BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { page = __first_valid_page(pfn, pageblock_nr_pages); if (page && set_migratetype_isolate(page)) { undo_pfn = pfn; goto undo; } } return 0; undo: for (pfn = start_pfn; |
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pfn < undo_pfn; |
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pfn += pageblock_nr_pages) |
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unset_migratetype_isolate(pfn_to_page(pfn), migratetype); |
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return -EBUSY; } /* * Make isolated pages available again. */ |
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int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn, unsigned migratetype) |
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{ unsigned long pfn; struct page *page; BUG_ON((start_pfn) & (pageblock_nr_pages - 1)); BUG_ON((end_pfn) & (pageblock_nr_pages - 1)); for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { page = __first_valid_page(pfn, pageblock_nr_pages); |
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if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
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continue; |
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unset_migratetype_isolate(page, migratetype); |
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} return 0; } /* * Test all pages in the range is free(means isolated) or not. * all pages in [start_pfn...end_pfn) must be in the same zone. * zone->lock must be held before call this. * |
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* Returns 1 if all pages in the range are isolated. |
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*/ static int __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn) { struct page *page; while (pfn < end_pfn) { if (!pfn_valid_within(pfn)) { pfn++; continue; } page = pfn_to_page(pfn); if (PageBuddy(page)) pfn += 1 << page_order(page); else if (page_count(page) == 0 && page_private(page) == MIGRATE_ISOLATE) pfn += 1; else break; } if (pfn < end_pfn) return 0; return 1; } int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn) { |
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unsigned long pfn, flags; |
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struct page *page; |
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struct zone *zone; int ret; |
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/* * Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page * is not aligned to pageblock_nr_pages. * Then we just check pagetype fist. */ for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) { page = __first_valid_page(pfn, pageblock_nr_pages); |
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if (page && get_pageblock_migratetype(page) != MIGRATE_ISOLATE) |
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break; } |
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page = __first_valid_page(start_pfn, end_pfn - start_pfn); if ((pfn < end_pfn) || !page) |
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return -EBUSY; /* Check all pages are free or Marked as ISOLATED */ |
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zone = page_zone(page); |
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spin_lock_irqsave(&zone->lock, flags); ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn); spin_unlock_irqrestore(&zone->lock, flags); return ret ? 0 : -EBUSY; |
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} |