diff --git a/include/qemu/thread-win32.h b/include/qemu/thread-win32.h index 5fb6541ae9..4c4a261cf4 100644 --- a/include/qemu/thread-win32.h +++ b/include/qemu/thread-win32.h @@ -4,8 +4,7 @@ #include struct QemuMutex { - CRITICAL_SECTION lock; - LONG owner; + SRWLOCK lock; }; typedef struct QemuRecMutex QemuRecMutex; @@ -19,9 +18,7 @@ int qemu_rec_mutex_trylock(QemuRecMutex *mutex); void qemu_rec_mutex_unlock(QemuRecMutex *mutex); struct QemuCond { - LONG waiters, target; - HANDLE sema; - HANDLE continue_event; + CONDITION_VARIABLE var; }; struct QemuSemaphore { diff --git a/util/qemu-thread-win32.c b/util/qemu-thread-win32.c index 29c3e4dd85..59befd5202 100644 --- a/util/qemu-thread-win32.c +++ b/util/qemu-thread-win32.c @@ -10,6 +10,11 @@ * See the COPYING file in the top-level directory. * */ + +#ifndef _WIN32_WINNT +#define _WIN32_WINNT 0x0600 +#endif + #include "qemu/osdep.h" #include "qemu-common.h" #include "qemu/thread.h" @@ -39,44 +44,30 @@ static void error_exit(int err, const char *msg) void qemu_mutex_init(QemuMutex *mutex) { - mutex->owner = 0; - InitializeCriticalSection(&mutex->lock); + InitializeSRWLock(&mutex->lock); } void qemu_mutex_destroy(QemuMutex *mutex) { - assert(mutex->owner == 0); - DeleteCriticalSection(&mutex->lock); + InitializeSRWLock(&mutex->lock); } void qemu_mutex_lock(QemuMutex *mutex) { - EnterCriticalSection(&mutex->lock); - - /* Win32 CRITICAL_SECTIONs are recursive. Assert that we're not - * using them as such. - */ - assert(mutex->owner == 0); - mutex->owner = GetCurrentThreadId(); + AcquireSRWLockExclusive(&mutex->lock); } int qemu_mutex_trylock(QemuMutex *mutex) { int owned; - owned = TryEnterCriticalSection(&mutex->lock); - if (owned) { - assert(mutex->owner == 0); - mutex->owner = GetCurrentThreadId(); - } + owned = TryAcquireSRWLockExclusive(&mutex->lock); return !owned; } void qemu_mutex_unlock(QemuMutex *mutex) { - assert(mutex->owner == GetCurrentThreadId()); - mutex->owner = 0; - LeaveCriticalSection(&mutex->lock); + ReleaseSRWLockExclusive(&mutex->lock); } void qemu_rec_mutex_init(QemuRecMutex *mutex) @@ -107,124 +98,27 @@ void qemu_rec_mutex_unlock(QemuRecMutex *mutex) void qemu_cond_init(QemuCond *cond) { memset(cond, 0, sizeof(*cond)); - - cond->sema = CreateSemaphore(NULL, 0, LONG_MAX, NULL); - if (!cond->sema) { - error_exit(GetLastError(), __func__); - } - cond->continue_event = CreateEvent(NULL, /* security */ - FALSE, /* auto-reset */ - FALSE, /* not signaled */ - NULL); /* name */ - if (!cond->continue_event) { - error_exit(GetLastError(), __func__); - } + InitializeConditionVariable(&cond->var); } void qemu_cond_destroy(QemuCond *cond) { - BOOL result; - result = CloseHandle(cond->continue_event); - if (!result) { - error_exit(GetLastError(), __func__); - } - cond->continue_event = 0; - result = CloseHandle(cond->sema); - if (!result) { - error_exit(GetLastError(), __func__); - } - cond->sema = 0; + InitializeConditionVariable(&cond->var); } void qemu_cond_signal(QemuCond *cond) { - DWORD result; - - /* - * Signal only when there are waiters. cond->waiters is - * incremented by pthread_cond_wait under the external lock, - * so we are safe about that. - */ - if (cond->waiters == 0) { - return; - } - - /* - * Waiting threads decrement it outside the external lock, but - * only if another thread is executing pthread_cond_broadcast and - * has the mutex. So, it also cannot be decremented concurrently - * with this particular access. - */ - cond->target = cond->waiters - 1; - result = SignalObjectAndWait(cond->sema, cond->continue_event, - INFINITE, FALSE); - if (result == WAIT_ABANDONED || result == WAIT_FAILED) { - error_exit(GetLastError(), __func__); - } + WakeConditionVariable(&cond->var); } void qemu_cond_broadcast(QemuCond *cond) { - BOOLEAN result; - /* - * As in pthread_cond_signal, access to cond->waiters and - * cond->target is locked via the external mutex. - */ - if (cond->waiters == 0) { - return; - } - - cond->target = 0; - result = ReleaseSemaphore(cond->sema, cond->waiters, NULL); - if (!result) { - error_exit(GetLastError(), __func__); - } - - /* - * At this point all waiters continue. Each one takes its - * slice of the semaphore. Now it's our turn to wait: Since - * the external mutex is held, no thread can leave cond_wait, - * yet. For this reason, we can be sure that no thread gets - * a chance to eat *more* than one slice. OTOH, it means - * that the last waiter must send us a wake-up. - */ - WaitForSingleObject(cond->continue_event, INFINITE); + WakeAllConditionVariable(&cond->var); } void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex) { - /* - * This access is protected under the mutex. - */ - cond->waiters++; - - /* - * Unlock external mutex and wait for signal. - * NOTE: we've held mutex locked long enough to increment - * waiters count above, so there's no problem with - * leaving mutex unlocked before we wait on semaphore. - */ - qemu_mutex_unlock(mutex); - WaitForSingleObject(cond->sema, INFINITE); - - /* Now waiters must rendez-vous with the signaling thread and - * let it continue. For cond_broadcast this has heavy contention - * and triggers thundering herd. So goes life. - * - * Decrease waiters count. The mutex is not taken, so we have - * to do this atomically. - * - * All waiters contend for the mutex at the end of this function - * until the signaling thread relinquishes it. To ensure - * each waiter consumes exactly one slice of the semaphore, - * the signaling thread stops until it is told by the last - * waiter that it can go on. - */ - if (InterlockedDecrement(&cond->waiters) == cond->target) { - SetEvent(cond->continue_event); - } - - qemu_mutex_lock(mutex); + SleepConditionVariableSRW(&cond->var, &mutex->lock, INFINITE, 0); } void qemu_sem_init(QemuSemaphore *sem, int init)