PERFORCE change 96747 for review

[Kip Macy]

http://perforce.freebsd.org/chv.cgi?CH=96747

Change 96747 by kmacy at kmacy_storage:sun4v_rwbuf on 2006/05/06 20:11:36

	fix tte_hash_lookup_last_inline
	generalize number of hash entries

Affected files ...

.. //depot/projects/kmacy_sun4v/src/sys/sun4v/sun4v/tte_hash.c#23 edit

Differences ...

==== //depot/projects/kmacy_sun4v/src/sys/sun4v/sun4v/tte_hash.c#23 (text+ko) ====

@@ -62,10 +62,11 @@
 #define MAX_HASH_SIZE    16
 #define HASH_MASK(th) ((th->th_size << (PAGE_SHIFT - THE_SHIFT)) - 1)
 #define HASH_VALID     0x1
+#define HASH_ENTRIES     4
 
+#define NULL_TAG         0
 
 
-
 struct tte_hash_entry;
 
 #define MAX_FRAGMENT_ENTRIES ((PAGE_SIZE / sizeof(struct tte_hash_entry)) - 1)
@@ -83,7 +84,7 @@
 
 
 typedef struct tte_hash_entry {
-	tte_hash_field the_fields[4];
+	tte_hash_field the_fields[HASH_ENTRIES];
 } *tte_hash_entry_t;
 
 
@@ -338,20 +339,23 @@
 	entry = 0;
 
 retry:
-	for (i = 0; i < 4 && fields[i].tte.tag != 0; i++) {
+	for (i = 0; i < HASH_ENTRIES && fields[i].tte.tag != 0; i++) {
 		if (((fields[i].tte.tag << TTARGET_VA_SHIFT) == (va & ~PAGE_MASK_4M))) {
 			entry = (fields[i].tte.data & ~VTD_LOCK);
 			break;
 		}
 	}
-	if (i == 4) {
-		if (fields[3].of.flags & TH_COLLISION) {
-			fields = fields[3].of.next;
+	if (i == HASH_ENTRIES) {
+		if (fields[(HASH_ENTRIES - 1)].of.flags & TH_COLLISION) {
+			fields = fields[(HASH_ENTRIES - 1)].of.next;
 			goto retry;
 		} 
-		i = 3;
+		i = (HASH_ENTRIES - 1);
 	} 
 
+	if (i >= HASH_ENTRIES)
+		panic("invalid state");
+
 	if (field) 
 		*field = &fields[i];
 
@@ -364,33 +368,40 @@
 {
 	uint64_t hash_shift, hash_index;
 	tte_hash_field_t fields;
-	int i;
+	int i, index;
 	/* XXX - only handle 8K pages for now */
 
 	hash_shift = PAGE_SHIFT;
 	hash_index = (va >> hash_shift) & HASH_MASK(th);
 	fields = (th->th_hashtable[hash_index].the_fields);
+	index = -1;;
+	
 
 retry:
-	for (i = 0; i < 4 && fields[i + 1].tte.tag != 0; i++) 
-		;
+	for (i = 0; i < (HASH_ENTRIES - 1); i++) 
+		if (fields[i + 1].tte.tag == 0) {
+			index = i;
+			break;
+		}
 
-	if (i == 4) {
-		if (fields[3].of.flags & TH_COLLISION) {
-			if (fields[3].of.next[0].tte.tag != 0) {
-				fields = fields[3].of.next; 
+	if (index != -1) 
+		*field = &fields[index];
+	else {
+		if (fields[(HASH_ENTRIES - 1)].of.flags & TH_COLLISION) {
+			if (fields[(HASH_ENTRIES - 1)].of.next[0].tte.tag != 0) {
+				fields = fields[(HASH_ENTRIES - 1)].of.next; 
 				goto retry;
 			} else {
 				/* 3rd entry is last */
-				*field = &fields[2];
+				*field = &fields[(HASH_ENTRIES - 2)];
 				/* clear collision pointer */
-				tte_hash_set_field(&fields[3], 0, 0);
+				tte_hash_set_field(&fields[(HASH_ENTRIES - 1)], 0, 0);
 
 			}
 		} else
-			*field = &fields[3]; /* 4th is the last entry */
-	} else 
-		*field = &fields[i];
+			*field = &fields[(HASH_ENTRIES - 1)]; /* last in bucket */
+	}
+		
 }