static bool debug_low_async_space_locked()

in binder_alloc.c [341:382]

• 28 lines of code
• 7 McCabe index (conditional complexity)

static bool debug_low_async_space_locked(struct binder_alloc *alloc, int pid)
{
	/*
	 * Find the amount and size of buffers allocated by the current caller;
	 * The idea is that once we cross the threshold, whoever is responsible
	 * for the low async space is likely to try to send another async txn,
	 * and at some point we'll catch them in the act. This is more efficient
	 * than keeping a map per pid.
	 */
	struct rb_node *n;
	struct binder_buffer *buffer;
	size_t total_alloc_size = 0;
	size_t num_buffers = 0;

	for (n = rb_first(&alloc->allocated_buffers); n != NULL;
		 n = rb_next(n)) {
		buffer = rb_entry(n, struct binder_buffer, rb_node);
		if (buffer->pid != pid)
			continue;
		if (!buffer->async_transaction)
			continue;
		total_alloc_size += binder_alloc_buffer_size(alloc, buffer)
			+ sizeof(struct binder_buffer);
		num_buffers++;
	}

	/*
	 * Warn if this pid has more than 50 transactions, or more than 50% of
	 * async space (which is 25% of total buffer size). Oneway spam is only
	 * detected when the threshold is exceeded.
	 */
	if (num_buffers > 50 || total_alloc_size > alloc->buffer_size / 4) {
		binder_alloc_debug(BINDER_DEBUG_USER_ERROR,
			     "%d: pid %d spamming oneway? %zd buffers allocated for a total size of %zd\n",
			      alloc->pid, pid, num_buffers, total_alloc_size);
		if (!alloc->oneway_spam_detected) {
			alloc->oneway_spam_detected = true;
			return true;
		}
	}
	return false;
}