include/linux/pageblock-flags.h

   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
  26 #include <linux/types.h>
  27
  28 /* Macro to aid the definition of ranges of bits */
  29 #define PB_range(name, required_bits) \
  30         name, name ## _end = (name + required_bits) - 1
  31
  32 /* Bit indices that affect a whole block of pages */
  33 enum pageblock_bits {
  34         PB_range(PB_migrate, 3), /* 3 bits required for migrate types */
  35         NR_PAGEBLOCK_BITS
  36 };
  37
  38 #ifdef CONFIG_HUGETLB_PAGE
  39
  40 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  41
  42 /* Huge page sizes are variable */
  43 extern int pageblock_order;
  44
  45 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  46
  47 /* Huge pages are a constant size */
  48 #define pageblock_order         HUGETLB_PAGE_ORDER
  49
  50 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  51
  52 #else /* CONFIG_HUGETLB_PAGE */
  53
  54 /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
  55 #define pageblock_order         (MAX_ORDER-1)
  56
  57 #endif /* CONFIG_HUGETLB_PAGE */
  58
  59 #define pageblock_nr_pages      (1UL << pageblock_order)
  60
  61 /* Forward declaration */
  62 struct page;
  63
  64 /* Declarations for getting and setting flags. See mm/page_alloc.c */
  65 unsigned long get_pageblock_flags_group(struct page *page,
  66                                         int start_bitidx, int end_bitidx);
  67 void set_pageblock_flags_group(struct page *page, unsigned long flags,
  68                                         int start_bitidx, int end_bitidx);
  69
  70 #define get_pageblock_flags(page) \
  71                         get_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
  72 #define set_pageblock_flags(page) \
  73                         set_pageblock_flags_group(page, 0, NR_PAGEBLOCK_BITS-1)
  74
  75 #endif  /* PAGEBLOCK_FLAGS_H */