pageblock-flags.h 2.3 KB

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  1. /*
  2. * Macros for manipulating and testing flags related to a
  3. * pageblock_nr_pages number of pages.
  4. *
  5. * This program is free software; you can redistribute it and/or modify
  6. * it under the terms of the GNU General Public License as published by
  7. * the Free Software Foundation version 2 of the License
  8. *
  9. * This program is distributed in the hope that it will be useful,
  10. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  12. * GNU General Public License for more details.
  13. *
  14. * You should have received a copy of the GNU General Public License
  15. * along with this program; if not, write to the Free Software
  16. * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17. *
  18. * Copyright (C) IBM Corporation, 2006
  19. *
  20. * Original author, Mel Gorman
  21. * Major cleanups and reduction of bit operations, Andy Whitcroft
  22. */
  23. #ifndef PAGEBLOCK_FLAGS_H
  24. #define PAGEBLOCK_FLAGS_H
  25. #include <linux/types.h>
  26. /* Macro to aid the definition of ranges of bits */
  27. #define PB_range(name, required_bits) \
  28. name, name ## _end = (name + required_bits) - 1
  29. /* Bit indices that affect a whole block of pages */
  30. enum pageblock_bits {
  31. PB_range(PB_migrate, 2), /* 2 bits required for migrate types */
  32. NR_PAGEBLOCK_BITS
  33. };
  34. #ifdef CONFIG_HUGETLB_PAGE
  35. #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  36. /* Huge page sizes are variable */
  37. extern int pageblock_order;
  38. #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  39. /* Huge pages are a constant size */
  40. #define pageblock_order HUGETLB_PAGE_ORDER
  41. #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  42. #else /* CONFIG_HUGETLB_PAGE */
  43. /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
  44. #define pageblock_order (MAX_ORDER-1)
  45. #endif /* CONFIG_HUGETLB_PAGE */
  46. #define pageblock_nr_pages (1UL << pageblock_order)
  47. /* Forward declaration */
  48. struct page;
  49. /* Declarations for getting and setting flags. See mm/page_alloc.c */
  50. unsigned long get_pageblock_flags_group(struct page *page,
  51. int start_bitidx, int end_bitidx);
  52. void set_pageblock_flags_group(struct page *page, unsigned long flags,
  53. int start_bitidx, int end_bitidx);
  54. #define get_pageblock_flags(page) \
  55. get_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
  56. #define set_pageblock_flags(page) \
  57. set_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
  58. #endif /* PAGEBLOCK_FLAGS_H */