free memory after 100 Mo allocated

communication_techniques/src/communication/jikes_barrier.c

@@ -30,6 +30,7 @@ static __thread void **local_tail = NULL;
 static __thread void **local_tail_buffer_end = NULL;
 static struct double_linked_list *global_tail = NULL;
 static struct double_linked_list *global_head = NULL;
+static int collect = 0;
 static int bufsenqueued = 0;
 static unsigned int lock = 0;
 
@@ -44,7 +45,7 @@ int init_thread_comm(struct thread_comm *comm)
 		return -1;
 	}
 	local_tail = new_buffer + (USABLE_BUFFER_BYTES - BYTES_IN_ADDRESS -
-		(USABLE_BUFFER_BYTES % (1 << LOG_BYTES_IN_ADDRESS))) + BYTES_IN_ADDRESS; // The second parenthesis is equal to 0
+		(USABLE_BUFFER_BYTES % (1 << LOG_BYTES_IN_ADDRESS))) + BYTES_IN_ADDRESS; /* The second parenthesis is equal to 0 */
 	local_tail_buffer_end = local_tail;
 	return 0;
 }
@@ -93,7 +94,7 @@ static void spin_unlock(unsigned int *lock)
 		: "memory", "cc");
 }
 
-void enqueue(struct double_linked_list *list, int arity, int to_tail) // Insert in the shared buffer: tail here is the tail of the shared buffer
+void enqueue(struct double_linked_list *list, int arity, int to_tail) /* Insert in the shared buffer: tail here is the tail of the shared buffer */
 {
 	spin_lock(&lock);
 	if (to_tail)
@@ -135,34 +136,60 @@ void **normalizeTail(int arity)
 		src++;
 		buffer_start++;
 	}
-	return last; // Return the buffer address of the last address (if address goes from 0 to n then it's &buf[n]
+	return last; /* Return the buffer address of the last address (if address goes from 0 to n then it's &buf[n] */
 }
 
 void closeAndEnqueueTail(int arity)
 {
 	void **last;
-	if ((((uintptr_t) local_tail) & BUFFER_MASK) != 0) // prematurely closed, won't pass here if it comes from insert
+	if ((((uintptr_t) local_tail) & BUFFER_MASK) != 0) /* prematurely closed, won't pass here if it comes from insert */
 		last = normalizeTail(arity);
-	else // a full tail buffer
-		last = local_tail_buffer_end - BYTES_IN_ADDRESS; // last space in the buffer before the 8/16 bytes of metadata of the buffer
+	else /* a full tail buffer */
+		last = local_tail_buffer_end - BYTES_IN_ADDRESS; /* last space in the buffer before the 8/16 bytes of metadata of the buffer */
 	enqueue((struct double_linked_list *) ((uintptr_t) last + BYTES_IN_ADDRESS), arity, 1);
 }
 
 void checkForAsyncCollection(void)
 {
+	if (bufsenqueued >= 102400) /* We use more than 100 Mo */
+		collect = 1;
+}
+
+void free_pages(struct double_linked_list *list_cur)
+{
+	if (list_cur == NULL)
+		return;
+	spin_lock(&lock);
+	/* 
+	 * We may free some buffer allocated after this line is executed, thus
+	 * the real number of buffer enqueued could be bigger.
+	 * This is done to avoid to keep the lock during the while loop and for
+	 * checkForAsyncCollection to first start asking for a collection at
+	 * 100 Mo in the *worst* case
+	 */
+	bufsenqueued = 0;
+	spin_unlock(&lock);
+	while (global_head != list_cur) /* We know closeAndEnqueueTail() ask enqueue() to enqueue at tail */
+	{
+		void *buf_start;
+
+		buf_start = (void *) ((uintptr_t) global_head & BUFFER_MASK);
+		global_head = global_head->next;
+		free(buf_start);
+	}
 }
 
 void tailOverflow(int arity)
 {
 	void *new_buffer;
 	if (local_tail != NULL)
-		closeAndEnqueueTail(arity); // Add the buffer to the tail of the shared buffer
+		closeAndEnqueueTail(arity); /* Add the buffer to the tail of the shared buffer */
 	if (posix_memalign(&new_buffer, BUFFER_SIZE, BUFFER_SIZE))
 		fprintf(stderr, "Failed to allocate space for queue.  Is metadata virtual memory exhausted?");
 	local_tail = (void **) ((uintptr_t) new_buffer + (USABLE_BUFFER_BYTES - BYTES_IN_ADDRESS -
-		(USABLE_BUFFER_BYTES % (arity << LOG_BYTES_IN_ADDRESS))) + BYTES_IN_ADDRESS); // The second parenthesis is equal to 0
+		(USABLE_BUFFER_BYTES % (arity << LOG_BYTES_IN_ADDRESS))) + BYTES_IN_ADDRESS); /* The second parenthesis is equal to 0 */
 	local_tail_buffer_end = local_tail;
-	checkForAsyncCollection(); // possible side-effect of alloc()
+	checkForAsyncCollection(); /* possible side-effect of posix_memalign() */
 }
 
 void insert(void *addr)
@@ -175,8 +202,8 @@ void insert(void *addr)
 
 void reception(void (*on_receive)(void *))
 {
-	struct double_linked_list *list_cur;
 	void **buf_start, **buf_ptr;
+	struct double_linked_list *list_cur = NULL;
 
 	wait_initialization(); /* Not needed but here for equity with others techniques */
 	/* printf("Activate the consumer...\n"); */
@@ -189,6 +216,11 @@ void reception(void (*on_receive)(void *))
 		buf_start = (void **) (((uintptr_t) &list_cur->prev) & ~BUFFER_MASK);
 		for (buf_ptr = buf_start; buf_ptr != (void **) &list_cur->prev; buf_ptr++)
 			on_receive(*buf_ptr);
+		if (collect)
+		{
+			free_pages(list_cur);
+			collect = 0;
+		}
 		while (cont && (list_cur->next == NULL));
 	} while (cont);
 }