pdns/mtasker.hh

   1 /*
   2  * This file is part of PowerDNS or dnsdist.
   3  * Copyright -- PowerDNS.COM B.V. and its contributors
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of version 2 of the GNU General Public License as
   7  * published by the Free Software Foundation.
   8  *
   9  * In addition, for the avoidance of any doubt, permission is granted to
  10  * link this program with OpenSSL and to (re)distribute the binaries
  11  * produced as the result of such linking.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  21  */
  22 #pragma once
  23 #include <stdint.h>
  24 #include <queue>
  25 #include <vector>
  26 #include <map>
  27 #include <time.h>
  28 #include <boost/multi_index_container.hpp>
  29 #include <boost/multi_index/ordered_index.hpp>
  30 #include <boost/multi_index/key_extractors.hpp>
  31 #include "namespaces.hh"
  32 #include "misc.hh"
  33 #include "mtasker_context.hh"
  34 #include <memory>
  35 #include <boost/function.hpp>
  36 using namespace ::boost::multi_index;
  37
  38 // #define MTASKERTIMING 1
  39
  40 struct KeyTag {};
  41
  42 //! The main MTasker class
  43 /** The main MTasker class. See the main page for more information.
  44     \tparam EventKey Type of the key with which events are to be identified. Defaults to int.
  45     \tparam EventVal Type of the content or value of an event. Defaults to int. Cannot be set to void.
  46     \note The EventKey needs to have an operator< defined because it is used as the key of an associative array
  47 */
  48
  49 template<class EventKey=int, class EventVal=int> class MTasker
  50 {
  51 private:
  52   pdns_ucontext_t d_kernel;
  53   std::queue<int> d_runQueue;
  54   std::queue<int> d_zombiesQueue;
  55
  56   struct ThreadInfo
  57   {
  58         std::shared_ptr<pdns_ucontext_t> context;
  59         boost::function<void(void)> start;
  60         char* startOfStack;
  61         char* highestStackSeen;
  62 #ifdef MTASKERTIMING
  63         CPUTime dt;
  64         unsigned int totTime;
  65 #endif
  66   };
  67
  68   typedef std::map<int, ThreadInfo> mthreads_t;
  69   mthreads_t d_threads;
  70   size_t d_stacksize;
  71   size_t d_threadsCount;
  72   int d_tid;
  73   int d_maxtid;
  74
  75   EventVal d_waitval;
  76   enum waitstatusenum {Error=-1,TimeOut=0,Answer} d_waitstatus;
  77
  78 public:
  79   struct Waiter
  80   {
  81     EventKey key;
  82     std::shared_ptr<pdns_ucontext_t> context;
  83     struct timeval ttd;
  84     int tid;
  85   };
  86
  87   typedef multi_index_container<
  88     Waiter,
  89     indexed_by <
  90                 ordered_unique<member<Waiter,EventKey,&Waiter::key> >,
  91                 ordered_non_unique<tag<KeyTag>, member<Waiter,struct timeval,&Waiter::ttd> >
  92                >
  93   > waiters_t;
  94
  95   waiters_t d_waiters;
  96
  97   void initMainStackBounds()
  98   {
  99 #ifdef HAVE_FIBER_SANITIZER
 100     pthread_attr_t attr;
 101     pthread_attr_init(&attr);
 102     pthread_getattr_np(pthread_self(), &attr);
 103     pthread_attr_getstack(&attr, &t_mainStack, &t_mainStackSize);
 104     pthread_attr_destroy(&attr);
 105 #endif /* HAVE_FIBER_SANITIZER */
 106   }
 107
 108   //! Constructor
 109   /** Constructor with a small default stacksize. If any of your threads exceeds this stack, your application will crash.
 110       This limit applies solely to the stack, the heap is not limited in any way. If threads need to allocate a lot of data,
 111       the use of new/delete is suggested.
 112    */
 113   MTasker(size_t stacksize=16*8192) : d_stacksize(stacksize), d_threadsCount(0), d_tid(0), d_maxtid(0), d_waitstatus(Error)
 114   {
 115     initMainStackBounds();
 116
 117     // make sure our stack is 16-byte aligned to make all the architectures happy
 118     d_stacksize = d_stacksize >> 4 << 4;
 119   }
 120
 121   typedef void tfunc_t(void *); //!< type of the pointer that starts a thread
 122   int waitEvent(EventKey &key, EventVal *val=0, unsigned int timeoutMsec=0, struct timeval* now=0);
 123   void yield();
 124   int sendEvent(const EventKey& key, const EventVal* val=0);
 125   void getEvents(std::vector<EventKey>& events);
 126   void makeThread(tfunc_t *start, void* val);
 127   bool schedule(struct timeval* now=0);
 128   bool noProcesses() const;
 129   unsigned int numProcesses() const;
 130   int getTid() const;
 131   unsigned int getMaxStackUsage();
 132   unsigned int getUsec();
 133
 134 private:
 135   EventKey d_eventkey;   // for waitEvent, contains exact key it was awoken for
 136 };
 137 #include "mtasker.cc"