svn commit: r185141 - user/kmacy/HEAD_fast_multi_xmit/sys/sys

[Kip Macy]

Author: kmacy
Date: Fri Nov 21 04:37:38 2008
New Revision: 185141
URL: http://svn.freebsd.org/changeset/base/185141

Log:
  add sanity checking of buf ring functions under DEBUG_BUFRING

Modified:
  user/kmacy/HEAD_fast_multi_xmit/sys/sys/buf_ring.h

Modified: user/kmacy/HEAD_fast_multi_xmit/sys/sys/buf_ring.h
==============================================================================
--- user/kmacy/HEAD_fast_multi_xmit/sys/sys/buf_ring.h	Fri Nov 21 03:03:57 2008	(r185140)
+++ user/kmacy/HEAD_fast_multi_xmit/sys/sys/buf_ring.h	Fri Nov 21 04:37:38 2008	(r185141)
@@ -56,6 +56,15 @@
   #error "unknown compiler"
 #endif
 
+#if defined(INVARIANTS) && !defined(DEBUG_BUFRING)
+#define DEBUG_BUFRING 1
+#endif
+
+#ifdef DEBUG_BUFRING
+#include <sys/lock.h>
+#include <sys/mutex.h>
+#endif
+
 struct buf_ring {
 	volatile uint32_t	br_prod_head;
 	volatile uint32_t	br_prod_tail;	
@@ -70,11 +79,14 @@ struct buf_ring {
 	volatile uint32_t	br_cons_tail;
 	int		 	br_cons_size;
 	int              	br_cons_mask;
-
+	
 	/*
 	 * Pad out to next L2 cache line
 	 */
 	uint64_t	  	_pad1[14];
+#ifdef DEBUG_BUFRING
+	struct mtx		*br_lock;
+#endif	
 	void			*br_ring[0];
 };
 
@@ -85,7 +97,14 @@ buf_ring_enqueue(struct buf_ring *br, vo
 	uint32_t prod_head, prod_next;
 	uint32_t cons_tail;
 	int success;
-
+#ifdef DEBUG_BUFRING
+	int i;
+	for (i = br->br_cons_head; i != br->br_prod_head;
+	     i = ((i + 1) & br->br_cons_mask))
+		if(br->br_ring[i] == buf)
+			panic("buf=%p already enqueue at %d prod=%d cons=%d",
+			    buf, i, br->br_prod_tail, br->br_cons_tail);
+#endif	
 	critical_enter();
 	do {
 		prod_head = br->br_prod_head;
@@ -101,9 +120,10 @@ buf_ring_enqueue(struct buf_ring *br, vo
 		success = atomic_cmpset_int(&br->br_prod_head, prod_head,
 		    prod_next);
 	} while (success == 0);
-
-	KASSERT(br->br_ring[prod_head] == NULL, ("dangling value in enqueue"));
-	
+#ifdef DEBUG_BUFRING
+	if (br->br_ring[prod_head] != NULL)
+		panic("dangling value in enqueue");
+#endif	
 	br->br_ring[prod_head] = buf;
 	wmb();
 
@@ -115,6 +135,7 @@ buf_ring_enqueue(struct buf_ring *br, vo
 	while (br->br_prod_tail != prod_head)
 		cpu_spinwait();
 	br->br_prod_tail = prod_next;
+	mb();
 	critical_exit();
 	return (0);
 }
@@ -148,7 +169,7 @@ buf_ring_dequeue_mc(struct buf_ring *br)
 	} while (success == 0);		
 
 	buf = br->br_ring[cons_head];
-#ifdef INVARIANTS	
+#ifdef DEBUG_BUFRING
 	br->br_ring[cons_head] = NULL;
 #endif
 	mb();
@@ -192,14 +213,16 @@ buf_ring_dequeue_sc(struct buf_ring *br)
 	
 	br->br_cons_head = cons_next;
 	buf = br->br_ring[cons_head];
-#ifdef INVARIANTS	
+	mb();
+	
+#ifdef DEBUG_BUFRING
 	br->br_ring[cons_head] = NULL;
+	if (!mtx_owned(br->br_lock))
+		panic("lock not held on single consumer dequeue");
+	if (br->br_cons_tail != cons_head)
+		panic("inconsistent list cons_tail=%d cons_head=%d",
+		    br->br_cons_tail, cons_head);
 #endif
-	mb();
-	KASSERT(br->br_cons_tail == cons_head,
-	    ("inconsistent list cons_tail=%d cons_head=%d",
-		br->br_cons_tail, cons_head));
-
 	br->br_cons_tail = cons_next;
 	mb();
 	critical_exit();
@@ -235,7 +258,8 @@ buf_ring_count(struct buf_ring *br)
 	    & br->br_prod_mask);
 }
 
-struct buf_ring *buf_ring_alloc(int count, struct malloc_type *type, int flags);
+struct buf_ring *buf_ring_alloc(int count, struct malloc_type *type, int flags,
+    struct mtx *);
 void buf_ring_free(struct buf_ring *br, struct malloc_type *type);