a70dcb969f
My last bugfix here (adding zone->lock) introduced a new problem: Using page_zone(pfn_to_page(pfn)) to get the zone after the for() loop is wrong. pfn will then be >= end_pfn, which may be in a different zone or not present at all. This may lead to an addressing exception in page_zone() or spin_lock_irqsave(). Now I use __first_valid_page() again after the loop to find a valid page for page_zone(). Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Acked-by: Nathan Fontenot <nfont@austin.ibm.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
143 lines
3.6 KiB
C
143 lines
3.6 KiB
C
/*
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* linux/mm/page_isolation.c
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*/
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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, flags;
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struct page *page;
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struct zone *zone;
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int ret;
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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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page = __first_valid_page(start_pfn, end_pfn - start_pfn);
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if ((pfn < end_pfn) || !page)
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return -EBUSY;
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/* 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);
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ret = __test_page_isolated_in_pageblock(start_pfn, end_pfn);
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spin_unlock_irqrestore(&zone->lock, flags);
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return ret ? 0 : -EBUSY;
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}
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