feat: lru eviction policy on page caches

[lunaix-os.git] / lunaix-os / kernel / ds / lru.c

diff --git a/lunaix-os/kernel/ds/lru.c b/lunaix-os/kernel/ds/lru.c
new file mode 100644 (file)
index 0000000..ebabeef
--- /dev/null
+++ b/lunaix-os/kernel/ds/lru.c
@@ -0,0 +1,49 @@
+#include <lunaix/ds/lru.h>
+#include <lunaix/mm/valloc.h>
+
+struct llist_header zone_lead = { .next = &zone_lead, .prev = &zone_lead };
+
+struct lru_zone*
+lru_new_zone()
+{
+    struct lru_zone* zone = valloc(sizeof(struct lru_zone));
+    if (!zone) {
+        return NULL;
+    }
+
+    llist_init_head(&zone->lead_node);
+    llist_append(&zone_lead, &zone->zones);
+
+    return zone;
+}
+
+void
+lru_use_one(struct lru_zone* zone, struct lru_node* node)
+{
+    if (node->lru_nodes.next && node->lru_nodes.prev) {
+        llist_delete(&node->lru_nodes);
+    }
+
+    llist_prepend(&zone->lead_node, &node->lru_nodes);
+}
+
+struct lru_node*
+lru_evict_one(struct lru_zone* zone)
+{
+    struct llist_header* tail = zone->lead_node.prev;
+    if (tail == &zone->lead_node) {
+        return;
+    }
+
+    llist_delete(tail);
+
+    return container_of(tail, struct lru_node, lru_nodes);
+}
+
+void
+lru_remove(struct lru_node* node)
+{
+    if (node->lru_nodes.next && node->lru_nodes.prev) {
+        llist_delete(&node->lru_nodes);
+    }
+}
\ No newline at end of file