lunaix-os/kernel/ds/lru.c

   1 #include <lunaix/ds/lru.h>
   2 #include <lunaix/mm/valloc.h>
   3
   4 struct llist_header zone_lead = { .next = &zone_lead, .prev = &zone_lead };
   5
   6 struct lru_zone*
   7 lru_new_zone(evict_cb try_evict_cb)
   8 {
   9     struct lru_zone* zone = vzalloc(sizeof(struct lru_zone));
  10     if (!zone) {
  11         return NULL;
  12     }
  13
  14     zone->try_evict = try_evict_cb;
  15
  16     llist_init_head(&zone->lead_node);
  17     llist_append(&zone_lead, &zone->zones);
  18
  19     return zone;
  20 }
  21
  22 void
  23 lru_use_one(struct lru_zone* zone, struct lru_node* node)
  24 {
  25     if (node->lru_nodes.next && node->lru_nodes.prev) {
  26         llist_delete(&node->lru_nodes);
  27     }
  28
  29     llist_prepend(&zone->lead_node, &node->lru_nodes);
  30     zone->objects++;
  31 }
  32
  33 static void
  34 __do_evict(struct lru_zone* zone, struct llist_header* elem)
  35 {
  36     llist_delete(elem);
  37     if (!zone->try_evict(container_of(elem, struct lru_node, lru_nodes))) {
  38         llist_append(&zone->lead_node, elem);
  39     } else {
  40         zone->objects--;
  41     }
  42 }
  43
  44 void
  45 lru_evict_one(struct lru_zone* zone)
  46 {
  47     struct llist_header* tail = zone->lead_node.prev;
  48     if (tail == &zone->lead_node) {
  49         return;
  50     }
  51
  52     __do_evict(zone, tail);
  53 }
  54
  55 void
  56 lru_evict_half(struct lru_zone* zone)
  57 {
  58     int target = (int)(zone->objects / 2);
  59     struct llist_header* tail = zone->lead_node.prev;
  60     while (tail != &zone->lead_node && target > 0) {
  61         __do_evict(zone, tail);
  62         tail = tail->prev;
  63         target--;
  64     }
  65 }
  66
  67 void
  68 lru_remove(struct lru_zone* zone, struct lru_node* node)
  69 {
  70     if (node->lru_nodes.next && node->lru_nodes.prev) {
  71         llist_delete(&node->lru_nodes);
  72     }
  73     zone->objects--;
  74 }