hphp/runtime/vm/treadmill.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-2014 Facebook, Inc. (http://www.facebook.com)     |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_TREADMILL_H_
  18 #define incl_HPHP_TREADMILL_H_
  19
  20 #include <stdint.h>
  21 #include <memory>
  22
  23 namespace HPHP {
  24
  25 class Class;
  26 class Typedef;
  27
  28 namespace Treadmill {
  29
  30 /*
  31  * The Treadmill allows us to defer work until all currently-outstanding
  32  * requests have finished. We hook request start and finish. To defer
  33  * work, inherit from WorkItem and call Treadmill::WorkItem::enqueue.
  34  *
  35  * The work item will be called from base rank.
  36  */
  37 void startRequest();
  38 void finishRequest();
  39
  40 /*
  41  * Returns the oldest start time in seconds of all requests in flight.
  42  * If there are no requests in flight the return value is 0.
  43  * The value returned should be used as a conservative and true value
  44  * for the oldest start time of any request in flight. In that sense
  45  * the value is safe to compare against in a less-than relationship.
  46  */
  47 int64_t getOldestStartTime();
  48
  49 /*
  50  * Ask for memory to be freed (as in free, not delete) by the next
  51  * appropriate treadmill round.
  52  */
  53 void deferredFree(void*);
  54
  55 typedef int64_t GenCount;
  56
  57 class WorkItem {
  58  protected:
  59   GenCount m_gen;
  60   friend void finishRequest();
  61
  62  public:
  63   WorkItem();
  64   virtual ~WorkItem() { }
  65   virtual void operator()() = 0; // doesn't throw.
  66   static void enqueue(std::unique_ptr<WorkItem> gt);
  67 };
  68
  69 class FreeMemoryTrigger : public WorkItem {
  70   void* m_ptr;
  71  public:
  72   explicit FreeMemoryTrigger(void* ptr);
  73   virtual void operator()();
  74 };
  75
  76 }}
  77
  78 #endif