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diff --git a/src/ceph/src/common/PrioritizedQueue.h b/src/ceph/src/common/PrioritizedQueue.h
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+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+/*
+ * Ceph - scalable distributed file system
+ *
+ * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
+ *
+ * This is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License version 2.1, as published by the Free Software
+ * Foundation.  See file COPYING.
+ *
+ */
+
+#ifndef PRIORITY_QUEUE_H
+#define PRIORITY_QUEUE_H
+
+#include "common/Formatter.h"
+#include "common/OpQueue.h"
+
+/**
+ * Manages queue for normal and strict priority items
+ *
+ * On dequeue, the queue will select the lowest priority queue
+ * such that the q has bucket > cost of front queue item.
+ *
+ * If there is no such queue, we choose the next queue item for
+ * the highest priority queue.
+ *
+ * Before returning a dequeued item, we place into each bucket
+ * cost * (priority/total_priority) tokens.
+ *
+ * enqueue_strict and enqueue_strict_front queue items into queues
+ * which are serviced in strict priority order before items queued
+ * with enqueue and enqueue_front
+ *
+ * Within a priority class, we schedule round robin based on the class
+ * of type K used to enqueue items.  e.g. you could use entity_inst_t
+ * to provide fairness for different clients.
+ */
+template <typename T, typename K>
+class PrioritizedQueue : public OpQueue <T, K> {
+  int64_t total_priority;
+  int64_t max_tokens_per_subqueue;
+  int64_t min_cost;
+
+  typedef std::list<std::pair<unsigned, T> > ListPairs;
+
+  struct SubQueue {
+  private:
+    typedef std::map<K, ListPairs> Classes;
+    Classes q;
+    unsigned tokens, max_tokens;
+    int64_t size;
+    typename Classes::iterator cur;
+  public:
+    SubQueue(const SubQueue &other)
+      : q(other.q),
+	tokens(other.tokens),
+	max_tokens(other.max_tokens),
+	size(other.size),
+	cur(q.begin()) {}
+    SubQueue()
+      : tokens(0),
+	max_tokens(0),
+	size(0), cur(q.begin()) {}
+    void set_max_tokens(unsigned mt) {
+      max_tokens = mt;
+    }
+    unsigned get_max_tokens() const {
+      return max_tokens;
+    }
+    unsigned num_tokens() const {
+      return tokens;
+    }
+    void put_tokens(unsigned t) {
+      tokens += t;
+      if (tokens > max_tokens) {
+	tokens = max_tokens;
+      }
+    }
+    void take_tokens(unsigned t) {
+      if (tokens > t) {
+	tokens -= t;
+      } else {
+	tokens = 0;
+      }
+    }
+    void enqueue(K cl, unsigned cost, T item) {
+      q[cl].push_back(std::make_pair(cost, item));
+      if (cur == q.end())
+	cur = q.begin();
+      size++;
+    }
+    void enqueue_front(K cl, unsigned cost, T item) {
+      q[cl].push_front(std::make_pair(cost, item));
+      if (cur == q.end())
+	cur = q.begin();
+      size++;
+    }
+    std::pair<unsigned, T> front() const {
+      assert(!(q.empty()));
+      assert(cur != q.end());
+      return cur->second.front();
+    }
+    void pop_front() {
+      assert(!(q.empty()));
+      assert(cur != q.end());
+      cur->second.pop_front();
+      if (cur->second.empty()) {
+	q.erase(cur++);
+      } else {
+	++cur;
+      }
+      if (cur == q.end()) {
+	cur = q.begin();
+      }
+      size--;
+    }
+    unsigned length() const {
+      assert(size >= 0);
+      return (unsigned)size;
+    }
+    bool empty() const {
+      return q.empty();
+    }
+    void remove_by_class(K k, std::list<T> *out) {
+      typename Classes::iterator i = q.find(k);
+      if (i == q.end()) {
+	return;
+      }
+      size -= i->second.size();
+      if (i == cur) {
+	++cur;
+      }
+      if (out) {
+	for (typename ListPairs::reverse_iterator j =
+	       i->second.rbegin();
+	     j != i->second.rend();
+	     ++j) {
+	  out->push_front(j->second);
+	}
+      }
+      q.erase(i);
+      if (cur == q.end()) {
+	cur = q.begin();
+      }
+    }
+
+    void dump(ceph::Formatter *f) const {
+      f->dump_int("tokens", tokens);
+      f->dump_int("max_tokens", max_tokens);
+      f->dump_int("size", size);
+      f->dump_int("num_keys", q.size());
+      if (!empty()) {
+	f->dump_int("first_item_cost", front().first);
+      }
+    }
+  };
+
+  typedef std::map<unsigned, SubQueue> SubQueues;
+  SubQueues high_queue;
+  SubQueues queue;
+
+  SubQueue *create_queue(unsigned priority) {
+    typename SubQueues::iterator p = queue.find(priority);
+    if (p != queue.end()) {
+      return &p->second;
+    }
+    total_priority += priority;
+    SubQueue *sq = &queue[priority];
+    sq->set_max_tokens(max_tokens_per_subqueue);
+    return sq;
+  }
+
+  void remove_queue(unsigned priority) {
+    assert(queue.count(priority));
+    queue.erase(priority);
+    total_priority -= priority;
+    assert(total_priority >= 0);
+  }
+
+  void distribute_tokens(unsigned cost) {
+    if (total_priority == 0) {
+      return;
+    }
+    for (typename SubQueues::iterator i = queue.begin();
+	 i != queue.end();
+	 ++i) {
+      i->second.put_tokens(((i->first * cost) / total_priority) + 1);
+    }
+  }
+
+public:
+  PrioritizedQueue(unsigned max_per, unsigned min_c)
+    : total_priority(0),
+      max_tokens_per_subqueue(max_per),
+      min_cost(min_c)
+  {}
+
+  unsigned length() const final {
+    unsigned total = 0;
+    for (typename SubQueues::const_iterator i = queue.begin();
+	 i != queue.end();
+	 ++i) {
+      assert(i->second.length());
+      total += i->second.length();
+    }
+    for (typename SubQueues::const_iterator i = high_queue.begin();
+	 i != high_queue.end();
+	 ++i) {
+      assert(i->second.length());
+      total += i->second.length();
+    }
+    return total;
+  }
+
+  void remove_by_class(K k, std::list<T> *out = 0) final {
+    for (typename SubQueues::iterator i = queue.begin();
+	 i != queue.end();
+	 ) {
+      i->second.remove_by_class(k, out);
+      if (i->second.empty()) {
+	unsigned priority = i->first;
+	++i;
+	remove_queue(priority);
+      } else {
+	++i;
+      }
+    }
+    for (typename SubQueues::iterator i = high_queue.begin();
+	 i != high_queue.end();
+	 ) {
+      i->second.remove_by_class(k, out);
+      if (i->second.empty()) {
+	high_queue.erase(i++);
+      } else {
+	++i;
+      }
+    }
+  }
+
+  void enqueue_strict(K cl, unsigned priority, T item) final {
+    high_queue[priority].enqueue(cl, 0, item);
+  }
+
+  void enqueue_strict_front(K cl, unsigned priority, T item) final {
+    high_queue[priority].enqueue_front(cl, 0, item);
+  }
+
+  void enqueue(K cl, unsigned priority, unsigned cost, T item) final {
+    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) final {
+    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);
+  }
+
+  bool empty() const final {
+    assert(total_priority >= 0);
+    assert((total_priority == 0) || !(queue.empty()));
+    return queue.empty() && high_queue.empty();
+  }
+
+  T dequeue() final {
+    assert(!empty());
+
+    if (!(high_queue.empty())) {
+      T ret = high_queue.rbegin()->second.front().second;
+      high_queue.rbegin()->second.pop_front();
+      if (high_queue.rbegin()->second.empty()) {
+	high_queue.erase(high_queue.rbegin()->first);
+      }
+      return ret;
+    }
+
+    // if there are multiple buckets/subqueues with sufficient tokens,
+    // we behave like a strict priority queue among all subqueues that
+    // are eligible to run.
+    for (typename SubQueues::iterator i = queue.begin();
+	 i != queue.end();
+	 ++i) {
+      assert(!(i->second.empty()));
+      if (i->second.front().first < i->second.num_tokens()) {
+	T ret = i->second.front().second;
+	unsigned cost = i->second.front().first;
+	i->second.take_tokens(cost);
+	i->second.pop_front();
+	if (i->second.empty()) {
+	  remove_queue(i->first);
+	}
+	distribute_tokens(cost);
+	return ret;
+      }
+    }
+
+    // if no subqueues have sufficient tokens, we behave like a strict
+    // priority queue.
+    T ret = queue.rbegin()->second.front().second;
+    unsigned cost = queue.rbegin()->second.front().first;
+    queue.rbegin()->second.pop_front();
+    if (queue.rbegin()->second.empty()) {
+      remove_queue(queue.rbegin()->first);
+    }
+    distribute_tokens(cost);
+    return ret;
+  }
+
+  void dump(ceph::Formatter *f) const final {
+    f->dump_int("total_priority", total_priority);
+    f->dump_int("max_tokens_per_subqueue", max_tokens_per_subqueue);
+    f->dump_int("min_cost", min_cost);
+    f->open_array_section("high_queues");
+    for (typename SubQueues::const_iterator p = high_queue.begin();
+	 p != high_queue.end();
+	 ++p) {
+      f->open_object_section("subqueue");
+      f->dump_int("priority", p->first);
+      p->second.dump(f);
+      f->close_section();
+    }
+    f->close_section();
+    f->open_array_section("queues");
+    for (typename SubQueues::const_iterator p = queue.begin();
+	 p != queue.end();
+	 ++p) {
+      f->open_object_section("subqueue");
+      f->dump_int("priority", p->first);
+      p->second.dump(f);
+      f->close_section();
+    }
+    f->close_section();
+  }
+};
+
+#endif