Changeset c7ec94a4 in mainline for genarch/src/mm/page_ht.c

Timestamp:

2006-02-06T14:18:28Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

f5935ed

Parents:

214f5bb

Message:

Page hash table architectures now use generic hash table to manage
mappings.

File:

• genarch/src/mm/page_ht.c (modified) (6 diffs)

genarch/src/mm/page_ht.c

@@ -29 +29 @@
 #include <genarch/mm/page_ht.h>
 #include <mm/page.h>
+#include <arch/mm/page.h>
 #include <mm/frame.h>
 #include <mm/heap.h>
@@ -40 +41 @@
 #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);
 
 /**
@@ -47 +56 @@
 
 /**
- * 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;
-
-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);
+hash_table_t page_ht;
+
+/** Hash table operations for page hash table. */
+hash_table_operations_t ht_operations = {
+        .hash = hash,
+        .compare = compare,
+        .remove_callback = remove_callback
+};
 
 page_operations_t page_ht_operations = {
@@ -60 +73 @@
 };
 
+/** 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.
  *
@@ -74 +161 @@
 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);
 
-        t = HT_HASH(page, as->asid);
-        if (!HT_SLOT_EMPTY(t)) {
-        
-                /*
-                 * 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);
-                                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);
+        if (!hash_table_find(&page_ht, key)) {
+                t = (pte_t *) malloc(sizeof(pte_t));
+                ASSERT(t != NULL);
+        
+                hash_table_insert(&page_ht, key, &t->link);
         }
-        
-        HT_SET_RECORD(t, page, as->asid, frame, flags);
-        HT_SET_NEXT(t, NULL);
         
         spinlock_unlock(&page_ht_lock);
@@ -128 +192 @@
 pte_t *ht_mapping_find(as_t *as, __address page)
 {
-        pte_t *t;
+        link_t *hlp;
+        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;
-        }
+
+        hlp = hash_table_find(&page_ht, key);
+        if (hlp)
+                t = list_get_instance(hlp, pte_t, link);
+
         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]);
-                        while (t) {
-                                u = t;
-                                t = HT_GET_NEXT(t);
-                                free(u);                /* FIXME: use slab allocator for this */
-                        }
-                        HT_INVALIDATE_SLOT(&page_ht[i]);
-                }
-        }
-        spinlock_unlock(&page_ht_lock);
-}