WebSVN – HelenOS-historic – Diff – /kernel/trunk/genarch/src/mm/page_ht.c

  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <genarch/mm/page_ht.h>
 #include <mm/page.h>
+#include <arch/mm/page.h>
 #include <mm/frame.h>
 #include <mm/heap.h>
 #include <mm/as.h>
 #include <arch/mm/asid.h>
 #include <arch/types.h>
 #include <arch/asm.h>
 #include <synch/spinlock.h>
 #include <arch.h>
 #include <debug.h>
 #include <memstr.h>
+#include <adt/hash_table.h>
+static index_t hash(__native key[]);
+static bool compare(__native key[], count_t keys, link_t *item);
+static void remove_callback(link_t *item);
+static void ht_mapping_insert(as_t *as, __address page, __address frame, int flags);
+static pte_t *ht_mapping_find(as_t *as, __address page);
 /**
  * This lock protects the page hash table.
  */
 SPINLOCK_INITIALIZE(page_ht_lock);
 /**
- * Page hash table pointer.
+ * Page hash table.
  * The page hash table may be accessed only when page_ht_lock is held.
  */
-pte_t *page_ht = NULL;
+hash_table_t page_ht;
-static void ht_mapping_insert(as_t *as, __address page, __address frame, int flags);
+/** Hash table operations for page hash table. */
-static pte_t *ht_mapping_find(as_t *as, __address page);
+hash_table_operations_t ht_operations = {
+    .hash = hash,
+    .compare = compare,
+    .remove_callback = remove_callback
+};
 page_operations_t page_ht_operations = {
     .mapping_insert = ht_mapping_insert,
     .mapping_find = ht_mapping_find
 };
+/** Compute page hash table index.
+ *
+ * @param key Array of two keys (i.e. page and address space).
+ *
+ * @return Index into page hash table.
+ */
+index_t hash(__native key[])
+{
+    as_t *as = (as_t *) key[KEY_AS];
+    __address page = (__address) key[KEY_PAGE];
+    index_t index;
+    /*
+     * Virtual page addresses have roughly the same probability
+     * of occurring. Least significant bits of VPN compose the
+     * hash index.
+     */
+    index = ((page >> PAGE_WIDTH) & (PAGE_HT_ENTRIES-1));
+    /*
+     * Address space structures are likely to be allocated from
+     * similar addresses. Least significant bits compose the
+     * hash index.
+     */
+    index |= ((__native) as) & (PAGE_HT_ENTRIES-1);
+    return index;
+}
+/** Compare page hash table item with page and/or address space.
+ *
+ * @param key Array of one or two keys (i.e. page and/or address space).
+ * @param keys Number of keys passed.
+ * @param item Item to compare the keys with.
+ *
+ * @return true on match, false otherwise.
+ */
+bool compare(__native key[], count_t keys, link_t *item)
+{
+    pte_t *t;
+    ASSERT(item);
+    ASSERT((keys > 0) && (keys <= PAGE_HT_KEYS));
+    /*
+     * Convert item to PTE.
+     */
+    t = list_get_instance(item, pte_t, link);
+    if (keys == PAGE_HT_KEYS) {
+        return (key[KEY_AS] == (__address) t->as) && (key[KEY_PAGE] == t->page);
+    } else {
+        return (key[KEY_AS] == (__address) t->as);
+    }
+}
+/** Callback on page hash table item removal.
+ *
+ * @param item Page hash table item being removed.
+ */
+void remove_callback(link_t *item)
+{
+    pte_t *t;
+    ASSERT(item);
+    /*
+     * Convert item to PTE.
+     */
+    t = list_get_instance(item, pte_t, link);
+    free(t);
+}
 /** Map page to frame using page hash table.
+ *
  * Map virtual address 'page' to physical address 'frame'
  * using 'flags'.
+ *
  * @param frame Physical address of memory frame to which the mapping is done.
  * @param flags Flags to be used for mapping.
  */
 void ht_mapping_insert(as_t *as, __address page, __address frame, int flags)
+{
-    pte_t *t, *u;
+    pte_t *t;
     ipl_t ipl;
+    __native key[2] = { (__address) as, page };
     ipl = interrupts_disable();
     spinlock_lock(&page_ht_lock);
+    if (!hash_table_find(&page_ht, key)) {
-    t = HT_HASH(page, as->asid);
+        t = (pte_t *) malloc(sizeof(pte_t));
-    if (!HT_SLOT_EMPTY(t)) {
+        ASSERT(t != NULL);
-        /*
-         * The slot is occupied.
-         * Walk through the collision chain and append the mapping to its end.
-         */
-        do {
-            u = t;
-            if (HT_COMPARE(page, as->asid, t)) {
-                /*
-                 * Nothing to do,
-                 * the record is already there.
-                 */
-                spinlock_unlock(&page_ht_lock);
+        hash_table_insert(&page_ht, key, &t->link);
-                interrupts_restore(ipl);
-                return;
-            }
-        } while ((t = HT_GET_NEXT(t)));
-        t = (pte_t *) malloc(sizeof(pte_t));    /* FIXME: use slab allocator for this */
-        if (!t)
-            panic("could not allocate memory\n");
-        HT_SET_NEXT(u, t);
+    }
-    HT_SET_RECORD(t, page, as->asid, frame, flags);
-    HT_SET_NEXT(t, NULL);
     spinlock_unlock(&page_ht_lock);
     interrupts_restore(ipl);
+}
 /** Find mapping for virtual page in page hash table.
+ *
  * @return NULL if there is no such mapping; requested mapping otherwise.
  */
 pte_t *ht_mapping_find(as_t *as, __address page)
+{
+    link_t *hlp;
-    pte_t *t;
+    pte_t *t = NULL;
+    __native key[2] = { (__address) as, page };
     spinlock_lock(&page_ht_lock);
-    t = HT_HASH(page, as->asid);
-    if (!HT_SLOT_EMPTY(t)) {
-        while (!HT_COMPARE(page, as->asid, t) && HT_GET_NEXT(t))
-            t = HT_GET_NEXT(t);
-        t = HT_COMPARE(page, as->asid, t) ? t : NULL;
-    } else {
-        t = NULL;
-    }
-    spinlock_unlock(&page_ht_lock);
-    return t;
-}
-/** Invalidate page hash table.
- *
- * Interrupts must be disabled.
- */
-void ht_invalidate_all(void)
-{
-    pte_t *t, *u;
-    int i;
-    spinlock_lock(&page_ht_lock);
-    for (i = 0; i < HT_ENTRIES; i++) {
-        if (!HT_SLOT_EMPTY(&page_ht[i])) {
-            t = HT_GET_NEXT(&page_ht[i]);
+    hlp = hash_table_find(&page_ht, key);
-            while (t) {
+    if (hlp)
-                u = t;
-                t = HT_GET_NEXT(t);
-                free(u);        /* FIXME: use slab allocator for this */
-            }
-            HT_INVALIDATE_SLOT(&page_ht[i]);
+        t = list_get_instance(hlp, pte_t, link);
-        }
-    }
     spinlock_unlock(&page_ht_lock);
+    return t;
+}

Subversion Repositories HelenOS-historic

(root)/kernel/trunk/genarch/src/mm/page_ht.c – Rev 757 → 792