include/linux/pageblock-flags.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Macros for manipulating and testing flags related to a
   4  * pageblock_nr_pages number of pages.
   5  *
   6  * Copyright (C) IBM Corporation, 2006
   7  *
   8  * Original author, Mel Gorman
   9  * Major cleanups and reduction of bit operations, Andy Whitcroft
  10  */
  11 #ifndef PAGEBLOCK_FLAGS_H
  12 #define PAGEBLOCK_FLAGS_H
  13
  14 #include <linux/types.h>
  15
  16 #define PB_migratetype_bits 3
  17 /* Bit indices that affect a whole block of pages */
  18 enum pageblock_bits {
  19         PB_migrate,
  20         PB_migrate_end = PB_migrate + PB_migratetype_bits - 1,
  21                         /* 3 bits required for migrate types */
  22         PB_migrate_skip,/* If set the block is skipped by compaction */
  23
  24         /*
  25          * Assume the bits will always align on a word. If this assumption
  26          * changes then get/set pageblock needs updating.
  27          */
  28         NR_PAGEBLOCK_BITS
  29 };
  30
  31 #ifdef CONFIG_HUGETLB_PAGE
  32
  33 #ifdef CONFIG_HUGETLB_PAGE_SIZE_VARIABLE
  34
  35 /* Huge page sizes are variable */
  36 extern unsigned int pageblock_order;
  37
  38 #else /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  39
  40 /* Huge pages are a constant size */
  41 #define pageblock_order         HUGETLB_PAGE_ORDER
  42
  43 #endif /* CONFIG_HUGETLB_PAGE_SIZE_VARIABLE */
  44
  45 #else /* CONFIG_HUGETLB_PAGE */
  46
  47 /* If huge pages are not used, group by MAX_ORDER_NR_PAGES */
  48 #define pageblock_order         (MAX_ORDER-1)
  49
  50 #endif /* CONFIG_HUGETLB_PAGE */
  51
  52 #define pageblock_nr_pages      (1UL << pageblock_order)
  53
  54 /* Forward declaration */
  55 struct page;
  56
  57 unsigned long get_pfnblock_flags_mask(struct page *page,
  58                                 unsigned long pfn,
  59                                 unsigned long end_bitidx,
  60                                 unsigned long mask);
  61
  62 void set_pfnblock_flags_mask(struct page *page,
  63                                 unsigned long flags,
  64                                 unsigned long pfn,
  65                                 unsigned long end_bitidx,
  66                                 unsigned long mask);
  67
  68 /* Declarations for getting and setting flags. See mm/page_alloc.c */
  69 #define get_pageblock_flags_group(page, start_bitidx, end_bitidx) \
  70         get_pfnblock_flags_mask(page, page_to_pfn(page),                \
  71                         end_bitidx,                                     \
  72                         (1 << (end_bitidx - start_bitidx + 1)) - 1)
  73 #define set_pageblock_flags_group(page, flags, start_bitidx, end_bitidx) \
  74         set_pfnblock_flags_mask(page, flags, page_to_pfn(page),         \
  75                         end_bitidx,                                     \
  76                         (1 << (end_bitidx - start_bitidx + 1)) - 1)
  77
  78 #ifdef CONFIG_COMPACTION
  79 #define get_pageblock_skip(page) \
  80                         get_pageblock_flags_group(page, PB_migrate_skip,     \
  81                                                         PB_migrate_skip)
  82 #define clear_pageblock_skip(page) \
  83                         set_pageblock_flags_group(page, 0, PB_migrate_skip,  \
  84                                                         PB_migrate_skip)
  85 #define set_pageblock_skip(page) \
  86                         set_pageblock_flags_group(page, 1, PB_migrate_skip,  \
  87                                                         PB_migrate_skip)
  88 #else
  89 static inline bool get_pageblock_skip(struct page *page)
  90 {
  91         return false;
  92 }
  93 static inline void clear_pageblock_skip(struct page *page)
  94 {
  95 }
  96 static inline void set_pageblock_skip(struct page *page)
  97 {
  98 }
  99 #endif /* CONFIG_COMPACTION */
 100
 101 #endif  /* PAGEBLOCK_FLAGS_H */