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[/] [test_project/] [trunk/] [linux_sd_driver/] [mm/] [page_isolation.c] - Blame information for rev 62

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1 62 marcus.erl 
/*
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 * linux/mm/page_isolation.c
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 */
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#include <stddef.h>
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#include <linux/mm.h>
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#include <linux/page-isolation.h>
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#include <linux/pageblock-flags.h>
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#include "internal.h"
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static inline struct page *
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__first_valid_page(unsigned long pfn, unsigned long nr_pages)
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{
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        int i;
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        for (i = 0; i < nr_pages; i++)
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                if (pfn_valid_within(pfn + i))
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                        break;
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        if (unlikely(i == nr_pages))
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                return NULL;
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        return pfn_to_page(pfn + i);
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}
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/*
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 * start_isolate_page_range() -- make page-allocation-type of range of pages
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 * to be MIGRATE_ISOLATE.
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 * @start_pfn: The lower PFN of the range to be isolated.
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 * @end_pfn: The upper PFN of the range to be isolated.
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 *
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 * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
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 * the range will never be allocated. Any free pages and pages freed in the
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 * future will not be allocated again.
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 *
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 * start_pfn/end_pfn must be aligned to pageblock_order.
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 * Returns 0 on success and -EBUSY if any part of range cannot be isolated.
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 */
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int
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start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
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{
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        unsigned long pfn;
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        unsigned long undo_pfn;
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        struct page *page;
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        BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
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        BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
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        for (pfn = start_pfn;
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             pfn < end_pfn;
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             pfn += pageblock_nr_pages) {
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                page = __first_valid_page(pfn, pageblock_nr_pages);
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                if (page && set_migratetype_isolate(page)) {
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                        undo_pfn = pfn;
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                        goto undo;
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                }
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        }
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        return 0;
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undo:
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        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));
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        return -EBUSY;
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}
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/*
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 * Make isolated pages available again.
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 */
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int
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undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
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{
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        unsigned long pfn;
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        struct page *page;
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        BUG_ON((start_pfn) & (pageblock_nr_pages - 1));
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        BUG_ON((end_pfn) & (pageblock_nr_pages - 1));
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        for (pfn = start_pfn;
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             pfn < end_pfn;
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             pfn += pageblock_nr_pages) {
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                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);
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        }
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        return 0;
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}
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/*
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 * Test all pages in the range is free(means isolated) or not.
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 * all pages in [start_pfn...end_pfn) must be in the same zone.
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 * zone->lock must be held before call this.
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 *
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 * Returns 0 if all pages in the range is isolated.
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 */
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static int
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__test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn)
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{
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        struct page *page;
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        while (pfn < end_pfn) {
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                if (!pfn_valid_within(pfn)) {
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                        pfn++;
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                        continue;
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                }
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                page = pfn_to_page(pfn);
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                if (PageBuddy(page))
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                        pfn += 1 << page_order(page);
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                else if (page_count(page) == 0 &&
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                                page_private(page) == MIGRATE_ISOLATE)
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                        pfn += 1;
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                else
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                        break;
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        }
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        if (pfn < end_pfn)
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                return 0;
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        return 1;
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}
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int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn)
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{
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        unsigned long pfn;
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        struct page *page;
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        pfn = start_pfn;
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        /*
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         * Note: pageblock_nr_page != MAX_ORDER. Then, chunks of free page
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         * is not aligned to pageblock_nr_pages.
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         * Then we just check pagetype fist.
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         */
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        for (pfn = start_pfn; pfn < end_pfn; pfn += pageblock_nr_pages) {
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                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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        }
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        if (pfn < end_pfn)
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                return -EBUSY;
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        /* Check all pages are free or Marked as ISOLATED */
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        if (__test_page_isolated_in_pageblock(start_pfn, end_pfn))
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                return 0;
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        return -EBUSY;
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}

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