PrioritizedQueue: cap costs at max_tokens_per_subqueue

Otherwise, you can get a recovery op in the queue which has a cost
higher than the max token value.  It won't get serviced until all other
queues also do not have enough tokens and higher priority queues are
empty.

Fixes: #7706
Signed-off-by: Samuel Just <sam.just@inktank.com>

diff --git a/src/common/PrioritizedQueue.h b/src/common/PrioritizedQueue.h
index e663f277693ea51a28cf3d5f6c5d32262bc8ebf6..d936d5d86c4fe1aae8c06eb4117d313460d8462d 100644 (file)
--- a/src/common/PrioritizedQueue.h
+++ b/src/common/PrioritizedQueue.h
@@ -311,12 +311,16 @@ public:
   void enqueue(K cl, unsigned priority, unsigned cost, T item) {
     if (cost < min_cost)
       cost = min_cost;
+    if (cost > max_tokens_per_subqueue)
+      cost = max_tokens_per_subqueue;
     create_queue(priority)->enqueue(cl, cost, item);
   }
 
   void enqueue_front(K cl, unsigned priority, unsigned cost, T item) {
     if (cost < min_cost)
       cost = min_cost;
+    if (cost > max_tokens_per_subqueue)
+      cost = max_tokens_per_subqueue;
     create_queue(priority)->enqueue_front(cl, cost, item);
   }