ceph/src/mds/MDBalancer.h

   1 // -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
   2 // vim: ts=8 sw=2 smarttab
   3 /*
   4  * Ceph - scalable distributed file system
   5  *
   6  * Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
   7  *
   8  * This is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License version 2.1, as published by the Free Software
  11  * Foundation.  See file COPYING.
  12  *
  13  */
  14
  15
  16
  17 #ifndef CEPH_MDBALANCER_H
  18 #define CEPH_MDBALANCER_H
  19
  20 #include <list>
  21 #include <map>
  22 using std::list;
  23 using std::map;
  24
  25 #include "include/types.h"
  26 #include "common/Clock.h"
  27 #include "common/Cond.h"
  28
  29 class MDSRank;
  30 class Message;
  31 class MHeartbeat;
  32 class CInode;
  33 class CDir;
  34 class Messenger;
  35 class MonClient;
  36
  37 class MDBalancer {
  38   friend class C_Bal_SendHeartbeat;
  39 public:
  40   MDBalancer(MDSRank *m, Messenger *msgr, MonClient *monc) :
  41     mds(m),
  42     messenger(msgr),
  43     mon_client(monc),
  44     beat_epoch(0),
  45     last_epoch_under(0), last_epoch_over(0), my_load(0.0), target_load(0.0)
  46     { }
  47
  48   mds_load_t get_load(utime_t);
  49
  50   int proc_message(Message *m);
  51
  52   /**
  53    * Regularly called upkeep function.
  54    *
  55    * Sends MHeartbeat messages to the mons.
  56    */
  57   void tick();
  58
  59   void subtract_export(CDir *ex, utime_t now);
  60   void add_import(CDir *im, utime_t now);
  61
  62   void hit_inode(utime_t now, CInode *in, int type, int who=-1);
  63   void hit_dir(utime_t now, CDir *dir, int type, int who=-1, double amount=1.0);
  64
  65   void queue_split(const CDir *dir, bool fast);
  66   void queue_merge(CDir *dir);
  67
  68   /**
  69    * Based on size and configuration, decide whether to issue a queue_split
  70    * or queue_merge for this CDir.
  71    *
  72    * \param hot whether the directory's temperature is enough to split it
  73    */
  74   void maybe_fragment(CDir *dir, bool hot);
  75
  76 private:
  77   typedef struct {
  78     std::map<mds_rank_t, double> targets;
  79     std::map<mds_rank_t, double> imported;
  80     std::map<mds_rank_t, double> exported;
  81   } balance_state_t;
  82
  83   //set up the rebalancing targets for export and do one if the
  84   //MDSMap is up to date
  85   void prep_rebalance(int beat);
  86   int mantle_prep_rebalance();
  87
  88   void handle_export_pins(void);
  89
  90   void export_empties();
  91   int localize_balancer();
  92   void send_heartbeat();
  93   void handle_heartbeat(MHeartbeat *m);
  94   void find_exports(CDir *dir,
  95                     double amount,
  96                     list<CDir*>& exports,
  97                     double& have,
  98                     set<CDir*>& already_exporting);
  99
 100   double try_match(balance_state_t &state,
 101                    mds_rank_t ex, double& maxex,
 102                    mds_rank_t im, double& maxim);
 103
 104   double get_maxim(balance_state_t &state, mds_rank_t im) {
 105     return target_load - mds_meta_load[im] - state.imported[im];
 106   }
 107   double get_maxex(balance_state_t &state, mds_rank_t ex) {
 108     return mds_meta_load[ex] - target_load - state.exported[ex];
 109   }
 110
 111   /**
 112    * Try to rebalance.
 113    *
 114    * Check if the monitor has recorded the current export targets;
 115    * if it has then do the actual export. Otherwise send off our
 116    * export targets message again.
 117    */
 118   void try_rebalance(balance_state_t& state);
 119
 120   MDSRank *mds;
 121   Messenger *messenger;
 122   MonClient *mon_client;
 123   int beat_epoch;
 124
 125   int last_epoch_under;
 126   int last_epoch_over;
 127   string bal_code;
 128   string bal_version;
 129
 130   utime_t last_heartbeat;
 131   utime_t last_sample;
 132   utime_t rebalance_time; //ensure a consistent view of load for rebalance
 133
 134   // Dirfrags which are marked to be passed on to MDCache::[split|merge]_dir
 135   // just as soon as a delayed context comes back and triggers it.
 136   // These sets just prevent us from spawning extra timer contexts for
 137   // dirfrags that already have one in flight.
 138   set<dirfrag_t>   split_pending, merge_pending;
 139
 140   // per-epoch scatter/gathered info
 141   map<mds_rank_t, mds_load_t>  mds_load;
 142   map<mds_rank_t, double>       mds_meta_load;
 143   map<mds_rank_t, map<mds_rank_t, float> > mds_import_map;
 144
 145   // per-epoch state
 146   double          my_load, target_load;
 147 };
 148
 149 #endif