pool.c

 
#include <winpr/config.h>
 
#include <winpr/crt.h>
#include <winpr/sysinfo.h>
#include <winpr/pool.h>
#include <winpr/library.h>
 
#include "pool.h"
 
#ifdef WINPR_THREAD_POOL
 
#ifdef _WIN32
static INIT_ONCE init_once_module = INIT_ONCE_STATIC_INIT;
static PTP_POOL(WINAPI* pCreateThreadpool)(PVOID reserved);
static VOID(WINAPI* pCloseThreadpool)(PTP_POOL ptpp);
static BOOL(WINAPI* pSetThreadpoolThreadMinimum)(PTP_POOL ptpp, DWORD cthrdMic);
static VOID(WINAPI* pSetThreadpoolThreadMaximum)(PTP_POOL ptpp, DWORD cthrdMost);
 
static BOOL CALLBACK init_module(PINIT_ONCE once, PVOID param, PVOID* context)
{
  HMODULE kernel32 = LoadLibraryA("kernel32.dll");
  if (kernel32)
  {
    pCreateThreadpool = GetProcAddressAs(kernel32, "CreateThreadpool", void*);
    pCloseThreadpool = GetProcAddressAs(kernel32, "CloseThreadpool", void*);
    pSetThreadpoolThreadMinimum =
        GetProcAddressAs(kernel32, "SetThreadpoolThreadMinimum", void*);
    pSetThreadpoolThreadMaximum =
        GetProcAddressAs(kernel32, "SetThreadpoolThreadMaximum", void*);
  }
  return TRUE;
}
#endif
 
static TP_POOL DEFAULT_POOL = {
  0,       /* DWORD Minimum */
  500,     /* DWORD Maximum */
  nullptr, /* wArrayList* Threads */
  nullptr, /* wQueue* PendingQueue */
  nullptr, /* HANDLE TerminateEvent */
  nullptr, /* wCountdownEvent* WorkComplete */
};
 
static DWORD WINAPI thread_pool_work_func(LPVOID arg)
{
  DWORD status = 0;
  PTP_POOL pool = nullptr;
  PTP_WORK work = nullptr;
  HANDLE events[2];
  PTP_CALLBACK_INSTANCE callbackInstance = nullptr;
 
  pool = (PTP_POOL)arg;
 
  events[0] = pool->TerminateEvent;
  events[1] = Queue_Event(pool->PendingQueue);
 
  while (1)
  {
    status = WaitForMultipleObjects(2, events, FALSE, INFINITE);
 
    if (status == WAIT_OBJECT_0)
      break;
 
    if (status != (WAIT_OBJECT_0 + 1))
      break;
 
    callbackInstance = (PTP_CALLBACK_INSTANCE)Queue_Dequeue(pool->PendingQueue);
 
    if (callbackInstance)
    {
      work = callbackInstance->Work;
      work->WorkCallback(callbackInstance, work->CallbackParameter, work);
      CountdownEvent_Signal(pool->WorkComplete, 1);
      free(callbackInstance);
    }
  }
 
  ExitThread(0);
  return 0;
}
 
static void threads_close(void* thread)
{
  (void)WaitForSingleObject(thread, INFINITE);
  (void)CloseHandle(thread);
}
 
static BOOL InitializeThreadpool(PTP_POOL pool)
{
  BOOL rc = FALSE;
  wObject* obj = nullptr;
 
  if (pool->Threads)
    return TRUE;
 
  if (!(pool->PendingQueue = Queue_New(TRUE, -1, -1)))
    goto fail;
 
  if (!(pool->WorkComplete = CountdownEvent_New(0)))
    goto fail;
 
  if (!(pool->TerminateEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr)))
    goto fail;
 
  if (!(pool->Threads = ArrayList_New(TRUE)))
    goto fail;
 
  obj = ArrayList_Object(pool->Threads);
  obj->fnObjectFree = threads_close;
 
#if !defined(WINPR_THREADPOOL_DEFAULT_MIN_COUNT)
#error "WINPR_THREADPOOL_DEFAULT_MIN_COUNT must be defined"
#endif
#if !defined(WINPR_THREADPOOL_DEFAULT_MAX_COUNT)
#error "WINPR_THREADPOOL_DEFAULT_MAX_COUNT must be defined"
#endif
 
  {
    SYSTEM_INFO info = WINPR_C_ARRAY_INIT;
    GetSystemInfo(&info);
 
    DWORD min = info.dwNumberOfProcessors;
    DWORD max = info.dwNumberOfProcessors;
    if (info.dwNumberOfProcessors < WINPR_THREADPOOL_DEFAULT_MIN_COUNT)
      min = WINPR_THREADPOOL_DEFAULT_MIN_COUNT;
    if (info.dwNumberOfProcessors > WINPR_THREADPOOL_DEFAULT_MAX_COUNT)
      max = WINPR_THREADPOOL_DEFAULT_MAX_COUNT;
    if (min > max)
      min = max;
 
    if (!SetThreadpoolThreadMinimum(pool, min))
      goto fail;
 
    SetThreadpoolThreadMaximum(pool, max);
  }
 
  rc = TRUE;
 
fail:
  return rc;
}
 
PTP_POOL GetDefaultThreadpool(void)
{
  PTP_POOL pool = &DEFAULT_POOL;
 
  if (!InitializeThreadpool(pool))
    return nullptr;
 
  return pool;
}
 
PTP_POOL winpr_CreateThreadpool(PVOID reserved)
{
  PTP_POOL pool = nullptr;
#ifdef _WIN32
  if (!InitOnceExecuteOnce(&init_once_module, init_module, nullptr, nullptr))
    return nullptr;
  if (pCreateThreadpool)
    return pCreateThreadpool(reserved);
#else
  WINPR_UNUSED(reserved);
#endif
  if (!(pool = (PTP_POOL)calloc(1, sizeof(TP_POOL))))
    return nullptr;
 
  if (!InitializeThreadpool(pool))
  {
    winpr_CloseThreadpool(pool);
    return nullptr;
  }
 
  return pool;
}
 
VOID winpr_CloseThreadpool(PTP_POOL ptpp)
{
#ifdef _WIN32
  if (!InitOnceExecuteOnce(&init_once_module, init_module, nullptr, nullptr))
    return;
  if (pCloseThreadpool)
  {
    pCloseThreadpool(ptpp);
    return;
  }
#endif
  (void)SetEvent(ptpp->TerminateEvent);
 
  ArrayList_Free(ptpp->Threads);
  Queue_Free(ptpp->PendingQueue);
  CountdownEvent_Free(ptpp->WorkComplete);
  (void)CloseHandle(ptpp->TerminateEvent);
 
  {
    TP_POOL empty = WINPR_C_ARRAY_INIT;
    *ptpp = empty;
  }
 
  if (ptpp != &DEFAULT_POOL)
    free(ptpp);
}
 
BOOL winpr_SetThreadpoolThreadMinimum(PTP_POOL ptpp, DWORD cthrdMic)
{
  BOOL rc = FALSE;
#ifdef _WIN32
  if (!InitOnceExecuteOnce(&init_once_module, init_module, nullptr, nullptr))
    return FALSE;
  if (pSetThreadpoolThreadMinimum)
    return pSetThreadpoolThreadMinimum(ptpp, cthrdMic);
#endif
  ptpp->Minimum = cthrdMic;
 
  ArrayList_Lock(ptpp->Threads);
  while (ArrayList_Count(ptpp->Threads) < ptpp->Minimum)
  {
    HANDLE thread = CreateThread(nullptr, 0, thread_pool_work_func, (void*)ptpp, 0, nullptr);
    if (!thread)
      goto fail;
 
    if (!ArrayList_Append(ptpp->Threads, thread))
    {
      (void)CloseHandle(thread);
      goto fail;
    }
  }
 
  rc = TRUE;
fail:
  ArrayList_Unlock(ptpp->Threads);
 
  return rc;
}
 
VOID winpr_SetThreadpoolThreadMaximum(PTP_POOL ptpp, DWORD cthrdMost)
{
#ifdef _WIN32
  if (!InitOnceExecuteOnce(&init_once_module, init_module, nullptr, nullptr))
    return;
  if (pSetThreadpoolThreadMaximum)
  {
    pSetThreadpoolThreadMaximum(ptpp, cthrdMost);
    return;
  }
#endif
  ptpp->Maximum = cthrdMost;
 
  ArrayList_Lock(ptpp->Threads);
  if (ArrayList_Count(ptpp->Threads) > ptpp->Maximum)
  {
    (void)SetEvent(ptpp->TerminateEvent);
    ArrayList_Clear(ptpp->Threads);
    (void)ResetEvent(ptpp->TerminateEvent);
  }
  ArrayList_Unlock(ptpp->Threads);
  winpr_SetThreadpoolThreadMinimum(ptpp, ptpp->Minimum);
}
 
#endif /* WINPR_THREAD_POOL defined */