--- 2.6.22.10.clean/mm/backing-dev.c	2007-10-10 10:50:35.000000000 -0700
+++ 2.6.22.10/mm/backing-dev.c	2007-11-16 11:42:54.000000000 -0800
@@ -48,6 +48,10 @@ long congestion_wait(int rw, long timeou
 	DEFINE_WAIT(wait);
 	wait_queue_head_t *wqh = &congestion_wqh[rw];
 
+	if ((current->flags & PF_LESS_THROTTLE) && printk_ratelimit()) {
+		printk(KERN_WARNING "PF_LESS_THROTTLE process %s[%i] entered congestion_wait!\n", current->comm, current->pid);
+		dump_stack();
+	}
 	prepare_to_wait(wqh, &wait, TASK_UNINTERRUPTIBLE);
 	ret = io_schedule_timeout(timeout);
 	finish_wait(wqh, &wait);