include/linux/mm_inline.h

   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  */
  17 static 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
  26 static inline void
  27 add_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
  33 static inline void
  34 del_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
  40 static inline void
  41 del_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  */
  66 static 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  */
  88 static 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