ceph/src/mds/Mantle.cc

   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) 2016 Michael Sevilla <mikesevilla3@gmail.com>
   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 #include "mdstypes.h"
  16 #include "MDSRank.h"
  17 #include "Mantle.h"
  18 #include "msg/Messenger.h"
  19 #include "common/Clock.h"
  20 #include "CInode.h"
  21
  22 #include <fstream>
  23
  24 #define dout_context g_ceph_context
  25 #undef dout_prefix
  26 #define dout_prefix *_dout << "mds.mantle "
  27 #define mantle_dout(lvl) \
  28   do {\
  29     auto subsys = ceph_subsys_mds;\
  30     if ((dout_context)->_conf->subsys.should_gather(ceph_subsys_mds_balancer, lvl)) {\
  31       subsys = ceph_subsys_mds_balancer;\
  32     }\
  33     dout_impl(dout_context, ceph::dout::need_dynamic(subsys), lvl) dout_prefix
  34
  35 #define mantle_dendl dendl; } while (0)
  36
  37
  38 static int dout_wrapper(lua_State *L)
  39 {
  40   int level = luaL_checkinteger(L, 1);
  41   lua_concat(L, lua_gettop(L)-1);
  42   mantle_dout(ceph::dout::need_dynamic(level)) << lua_tostring(L, 2)
  43                                                << mantle_dendl;
  44   return 0;
  45 }
  46
  47 int Mantle::balance(std::string_view script,
  48                     mds_rank_t whoami,
  49                     const std::vector<std::map<std::string, double>> &metrics,
  50                     std::map<mds_rank_t, double> &my_targets)
  51 {
  52   lua_settop(L, 0); /* clear the stack */
  53
  54   /* load the balancer */
  55   if (luaL_loadstring(L, script.data())) {
  56     mantle_dout(0) << "WARNING: mantle could not load balancer: "
  57             << lua_tostring(L, -1) << mantle_dendl;
  58     return -EINVAL;
  59   }
  60
  61   /* tell the balancer which mds is making the decision */
  62   lua_pushinteger(L, (lua_Integer)whoami);
  63   lua_setglobal(L, "whoami");
  64
  65   /* global mds metrics to hold all dictionaries */
  66   lua_newtable(L);
  67
  68   /* push name of mds (i) and its metrics onto Lua stack */
  69   for (size_t i=0; i < metrics.size(); i++) {
  70     lua_newtable(L);
  71
  72     /* push values into this mds's table; setfield assigns key/pops val */
  73     for (const auto &it : metrics[i]) {
  74       lua_pushnumber(L, it.second);
  75       lua_setfield(L, -2, it.first.c_str());
  76     }
  77
  78     /* in global mds table at stack[-3], set k=stack[-1] to v=stack[-2] */
  79     lua_seti(L, -2, i);
  80   }
  81
  82   /* set the name of the global mds table */
  83   lua_setglobal(L, "mds");
  84
  85   ceph_assert(lua_gettop(L) == 1);
  86   if (lua_pcall(L, 0, 1, 0) != LUA_OK) {
  87     mantle_dout(0) << "WARNING: mantle could not execute script: "
  88             << lua_tostring(L, -1) << mantle_dendl;
  89     return -EINVAL;
  90   }
  91
  92   /* parse response by iterating over Lua stack */
  93   if (lua_istable(L, -1) == 0) {
  94     mantle_dout(0) << "WARNING: mantle script returned a malformed response" << mantle_dendl;
  95     return -EINVAL;
  96   }
  97
  98   /* fill in return value */
  99   for (lua_pushnil(L); lua_next(L, -2); lua_pop(L, 1)) {
 100     if (!lua_isinteger(L, -2) || !lua_isnumber(L, -1)) {
 101       mantle_dout(0) << "WARNING: mantle script returned a malformed response" << mantle_dendl;
 102       return -EINVAL;
 103     }
 104     mds_rank_t rank(lua_tointeger(L, -2));
 105     my_targets[rank] = lua_tonumber(L, -1);
 106   }
 107
 108   return 0;
 109 }
 110
 111 Mantle::Mantle (void)
 112 {
 113   /* build lua vm state */
 114   L = luaL_newstate();
 115   if (!L) {
 116     mantle_dout(0) << "WARNING: mantle could not load Lua state" << mantle_dendl;
 117     throw std::bad_alloc();
 118   }
 119
 120   /* balancer policies can use basic Lua functions */
 121   static const luaL_Reg loadedlibs[] = {
 122     {"_G", luaopen_base},
 123     {LUA_COLIBNAME, luaopen_coroutine},
 124     {LUA_STRLIBNAME, luaopen_string},
 125     {LUA_MATHLIBNAME, luaopen_math},
 126     {LUA_TABLIBNAME, luaopen_table},
 127     {LUA_UTF8LIBNAME, luaopen_utf8},
 128     {NULL, NULL}
 129   };
 130
 131   const luaL_Reg *lib;
 132   for (lib = loadedlibs; lib->func; lib++) {
 133       luaL_requiref(L, lib->name, lib->func, 1);
 134       lua_pop(L, 1);  /* remove lib */
 135   }
 136
 137   /* setup debugging */
 138   lua_register(L, "BAL_LOG", dout_wrapper);
 139 }