LXR linux/include/linux/mm

   1#ifndef LINUX_MM_INLINE_H
   2#define LINUX_MM_INLINE_H
   3
   4/**
   5 * page_is_file_cache - should the page be on a file LRU or anon LRU?
   6 * @page: the page to test
   7 *
   8 * Returns LRU_FILE if @page is page cache page backed by a regular filesystem,
   9 * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed.
  10 * Used by functions that manipulate the LRU lists, to sort a page
  11 * onto the right LRU list.
  12 *
  13 * We would like to get this info without a page flag, but the state
  14 * needs to survive until the page is last deleted from the LRU, which
  15 * could be as far down as __page_cache_release.
  16 */
  17static inline int page_is_file_cache(struct page *page)
  18{
  19        if (PageSwapBacked(page))
  20                return 0;
  21
  22        /* The page is page cache backed by a normal filesystem. */
  23        return LRU_FILE;
  24}
  25
  26static inline void
  27add_page_to_lru_list(struct zone *zone, struct page *page, enum lru_list l)
  28{
  29        list_add(&page->lru, &zone->lru[l].list);
  30        __inc_zone_state(zone, NR_LRU_BASE + l);
  31}
  32
  33static inline void
  34del_page_from_lru_list(struct zone *zone, struct page *page, enum lru_list l)
  35{
  36        list_del(&page->lru);
  37        __dec_zone_state(zone, NR_LRU_BASE + l);
  38}
  39
  40static inline void
  41del_page_from_lru(struct zone *zone, struct page *page)
  42{
  43        enum lru_list l = LRU_BASE;
  44
  45        list_del(&page->lru);
  46        if (PageUnevictable(page)) {
  47                __ClearPageUnevictable(page);
  48                l = LRU_UNEVICTABLE;
  49        } else {
  50                if (PageActive(page)) {
  51                        __ClearPageActive(page);
  52                        l += LRU_ACTIVE;
  53                }
  54                l += page_is_file_cache(page);
  55        }
  56        __dec_zone_state(zone, NR_LRU_BASE + l);
  57}
  58
  59/**
  60 * page_lru - which LRU list should a page be on?
  61 * @page: the page to test
  62 *
  63 * Returns the LRU list a page should be on, as an index
  64 * into the array of LRU lists.
  65 */
  66static inline enum lru_list page_lru(struct page *page)
  67{
  68        enum lru_list lru = LRU_BASE;
  69
  70        if (PageUnevictable(page))
  71                lru = LRU_UNEVICTABLE;
  72        else {
  73                if (PageActive(page))
  74                        lru += LRU_ACTIVE;
  75                lru += page_is_file_cache(page);
  76        }
  77
  78        return lru;
  79}
  80
  81/**
  82 * inactive_anon_is_low - check if anonymous pages need to be deactivated
  83 * @zone: zone to check
  84 *
  85 * Returns true if the zone does not have enough inactive anon pages,
  86 * meaning some active anon pages need to be deactivated.
  87 */
  88static inline int inactive_anon_is_low(struct zone *zone)
  89{
  90        unsigned long active, inactive;
  91
  92        active = zone_page_state(zone, NR_ACTIVE_ANON);
  93        inactive = zone_page_state(zone, NR_INACTIVE_ANON);
  94
  95        if (inactive * zone->inactive_ratio < active)
  96                return 1;
  97
  98        return 0;
  99}
 100#endif
 101