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 #ifndef MTASKER_HH
  23 #define MTASKER_HH
  24 #include <stdint.h>
  25 #include <queue>
  26 #include <vector>
  27 #include <map>
  28 #include <time.h>
  29 #include <boost/multi_index_container.hpp>
  30 #include <boost/multi_index/ordered_index.hpp>
  31 #include <boost/multi_index/key_extractors.hpp>
  32 #include "namespaces.hh"
  33 #include "misc.hh"
  34 #include "mtasker_context.hh"
  35 #include <memory>
  36 #include <boost/function.hpp>
  37 using namespace ::boost::multi_index;
  38
  39 // #define MTASKERTIMING 1
  40
  41 struct KeyTag {};
  42
  43 //! The main MTasker class
  44 /** The main MTasker class. See the main page for more information.
  45     \tparam EventKey Type of the key with which events are to be identified. Defaults to int.
  46     \tparam EventVal Type of the content or value of an event. Defaults to int. Cannot be set to void.
  47     \note The EventKey needs to have an operator< defined because it is used as the key of an associative array
  48 */
  49
  50 template<class EventKey=int, class EventVal=int> class MTasker
  51 {
  52 private:
  53   pdns_ucontext_t d_kernel;
  54   std::queue<int> d_runQueue;
  55   std::queue<int> d_zombiesQueue;
  56
  57   struct ThreadInfo
  58   {
  59         std::shared_ptr<pdns_ucontext_t> context;
  60         boost::function<void(void)> start;
  61         char* startOfStack;
  62         char* highestStackSeen;
  63 #ifdef MTASKERTIMING
  64         CPUTime dt;
  65         unsigned int totTime;
  66 #endif
  67   };
  68
  69   typedef std::map<int, ThreadInfo> mthreads_t;
  70   mthreads_t d_threads;
  71   size_t d_stacksize;
  72   size_t d_threadsCount;
  73   int d_tid;
  74   int d_maxtid;
  75
  76   EventVal d_waitval;
  77   enum waitstatusenum {Error=-1,TimeOut=0,Answer} d_waitstatus;
  78
  79 public:
  80   struct Waiter
  81   {
  82     EventKey key;
  83     std::shared_ptr<pdns_ucontext_t> context;
  84     struct timeval ttd;
  85     int tid;
  86   };
  87
  88   typedef multi_index_container<
  89     Waiter,
  90     indexed_by <
  91                 ordered_unique<member<Waiter,EventKey,&Waiter::key> >,
  92                 ordered_non_unique<tag<KeyTag>, member<Waiter,struct timeval,&Waiter::ttd> >
  93                >
  94   > waiters_t;
  95
  96   waiters_t d_waiters;
  97
  98   void initMainStackBounds()
  99   {
 100 #ifdef HAVE_FIBER_SANITIZER
 101     pthread_attr_t attr;
 102     pthread_attr_init(&attr);
 103     pthread_getattr_np(pthread_self(), &attr);
 104     pthread_attr_getstack(&attr, &t_mainStack, &t_mainStackSize);
 105     pthread_attr_destroy(&attr);
 106 #endif /* HAVE_FIBER_SANITIZER */
 107   }
 108
 109   //! Constructor
 110   /** Constructor with a small default stacksize. If any of your threads exceeds this stack, your application will crash.
 111       This limit applies solely to the stack, the heap is not limited in any way. If threads need to allocate a lot of data,
 112       the use of new/delete is suggested.
 113    */
 114   MTasker(size_t stacksize=16*8192) : d_stacksize(stacksize), d_threadsCount(0), d_tid(0), d_maxtid(0), d_waitstatus(Error)
 115   {
 116     initMainStackBounds();
 117
 118     // make sure our stack is 16-byte aligned to make all the architectures happy
 119     d_stacksize = d_stacksize >> 4 << 4;
 120   }
 121
 122   typedef void tfunc_t(void *); //!< type of the pointer that starts a thread
 123   int waitEvent(EventKey &key, EventVal *val=0, unsigned int timeoutMsec=0, struct timeval* now=0);
 124   void yield();
 125   int sendEvent(const EventKey& key, const EventVal* val=0);
 126   void getEvents(std::vector<EventKey>& events);
 127   void makeThread(tfunc_t *start, void* val);
 128   bool schedule(struct timeval* now=0);
 129   bool noProcesses() const;
 130   unsigned int numProcesses() const;
 131   int getTid() const;
 132   unsigned int getMaxStackUsage();
 133   unsigned int getUsec();
 134
 135 private:
 136   EventKey d_eventkey;   // for waitEvent, contains exact key it was awoken for
 137 };
 138 #include "mtasker.cc"
 139
 140 #endif // MTASKER_HH
 141