* See the COPYING file in the top-level directory.
*
*/
+
#include "qemu/osdep.h"
-#include "qemu-common.h"
#include "qemu/thread.h"
#include "qemu/notify.h"
+#include "qemu-thread-common.h"
#include <process.h>
static bool name_threads;
+typedef HRESULT (WINAPI *pSetThreadDescription) (HANDLE hThread,
+ PCWSTR lpThreadDescription);
+static pSetThreadDescription SetThreadDescriptionFunc;
+static HMODULE kernel32_module;
+
+static bool load_set_thread_description(void)
+{
+ static gsize _init_once = 0;
+
+ if (g_once_init_enter(&_init_once)) {
+ kernel32_module = LoadLibrary("kernel32.dll");
+ if (kernel32_module) {
+ SetThreadDescriptionFunc =
+ (pSetThreadDescription)GetProcAddress(kernel32_module,
+ "SetThreadDescription");
+ if (!SetThreadDescriptionFunc) {
+ FreeLibrary(kernel32_module);
+ }
+ }
+ g_once_init_leave(&_init_once, 1);
+ }
+
+ return !!SetThreadDescriptionFunc;
+}
+
void qemu_thread_naming(bool enable)
{
- /* But note we don't actually name them on Windows yet */
name_threads = enable;
- fprintf(stderr, "qemu: thread naming not supported on this host\n");
+ if (enable && !load_set_thread_description()) {
+ fprintf(stderr, "qemu: thread naming not supported on this host\n");
+ name_threads = false;
+ }
}
static void error_exit(int err, const char *msg)
void qemu_mutex_init(QemuMutex *mutex)
{
- mutex->owner = 0;
- InitializeCriticalSection(&mutex->lock);
+ InitializeSRWLock(&mutex->lock);
+ qemu_mutex_post_init(mutex);
}
void qemu_mutex_destroy(QemuMutex *mutex)
{
- assert(mutex->owner == 0);
- DeleteCriticalSection(&mutex->lock);
+ assert(mutex->initialized);
+ mutex->initialized = false;
+ InitializeSRWLock(&mutex->lock);
}
-void qemu_mutex_lock(QemuMutex *mutex)
+void qemu_mutex_lock_impl(QemuMutex *mutex, const char *file, const int line)
{
- EnterCriticalSection(&mutex->lock);
-
- /* Win32 CRITICAL_SECTIONs are recursive. Assert that we're not
- * using them as such.
- */
- assert(mutex->owner == 0);
- mutex->owner = GetCurrentThreadId();
+ assert(mutex->initialized);
+ qemu_mutex_pre_lock(mutex, file, line);
+ AcquireSRWLockExclusive(&mutex->lock);
+ qemu_mutex_post_lock(mutex, file, line);
}
-int qemu_mutex_trylock(QemuMutex *mutex)
+int qemu_mutex_trylock_impl(QemuMutex *mutex, const char *file, const int line)
{
int owned;
- owned = TryEnterCriticalSection(&mutex->lock);
+ assert(mutex->initialized);
+ owned = TryAcquireSRWLockExclusive(&mutex->lock);
if (owned) {
- assert(mutex->owner == 0);
- mutex->owner = GetCurrentThreadId();
+ qemu_mutex_post_lock(mutex, file, line);
+ return 0;
}
- return !owned;
+ return -EBUSY;
}
-void qemu_mutex_unlock(QemuMutex *mutex)
+void qemu_mutex_unlock_impl(QemuMutex *mutex, const char *file, const int line)
{
- assert(mutex->owner == GetCurrentThreadId());
- mutex->owner = 0;
- LeaveCriticalSection(&mutex->lock);
+ assert(mutex->initialized);
+ qemu_mutex_pre_unlock(mutex, file, line);
+ ReleaseSRWLockExclusive(&mutex->lock);
}
void qemu_rec_mutex_init(QemuRecMutex *mutex)
{
InitializeCriticalSection(&mutex->lock);
+ mutex->initialized = true;
}
void qemu_rec_mutex_destroy(QemuRecMutex *mutex)
{
+ assert(mutex->initialized);
+ mutex->initialized = false;
DeleteCriticalSection(&mutex->lock);
}
-void qemu_rec_mutex_lock(QemuRecMutex *mutex)
+void qemu_rec_mutex_lock_impl(QemuRecMutex *mutex, const char *file, int line)
{
+ assert(mutex->initialized);
EnterCriticalSection(&mutex->lock);
}
-int qemu_rec_mutex_trylock(QemuRecMutex *mutex)
+int qemu_rec_mutex_trylock_impl(QemuRecMutex *mutex, const char *file, int line)
{
+ assert(mutex->initialized);
return !TryEnterCriticalSection(&mutex->lock);
}
-void qemu_rec_mutex_unlock(QemuRecMutex *mutex)
+void qemu_rec_mutex_unlock_impl(QemuRecMutex *mutex, const char *file, int line)
{
+ assert(mutex->initialized);
LeaveCriticalSection(&mutex->lock);
}
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);
+ cond->initialized = true;
}
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;
+ assert(cond->initialized);
+ cond->initialized = false;
+ 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__);
- }
+ assert(cond->initialized);
+ 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);
+ assert(cond->initialized);
+ WakeAllConditionVariable(&cond->var);
}
-void qemu_cond_wait(QemuCond *cond, QemuMutex *mutex)
+void qemu_cond_wait_impl(QemuCond *cond, QemuMutex *mutex, const char *file, const int line)
{
- /*
- * This access is protected under the mutex.
- */
- cond->waiters++;
+ assert(cond->initialized);
+ qemu_mutex_pre_unlock(mutex, file, line);
+ SleepConditionVariableSRW(&cond->var, &mutex->lock, INFINITE, 0);
+ qemu_mutex_post_lock(mutex, file, line);
+}
- /*
- * 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);
+bool qemu_cond_timedwait_impl(QemuCond *cond, QemuMutex *mutex, int ms,
+ const char *file, const int line)
+{
+ int rc = 0;
- /* 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);
+ assert(cond->initialized);
+ trace_qemu_mutex_unlock(mutex, file, line);
+ if (!SleepConditionVariableSRW(&cond->var, &mutex->lock, ms, 0)) {
+ rc = GetLastError();
}
-
- qemu_mutex_lock(mutex);
+ trace_qemu_mutex_locked(mutex, file, line);
+ if (rc && rc != ERROR_TIMEOUT) {
+ error_exit(rc, __func__);
+ }
+ return rc != ERROR_TIMEOUT;
}
void qemu_sem_init(QemuSemaphore *sem, int init)
{
/* Manual reset. */
sem->sema = CreateSemaphore(NULL, init, LONG_MAX, NULL);
+ sem->initialized = true;
}
void qemu_sem_destroy(QemuSemaphore *sem)
{
+ assert(sem->initialized);
+ sem->initialized = false;
CloseHandle(sem->sema);
}
void qemu_sem_post(QemuSemaphore *sem)
{
+ assert(sem->initialized);
ReleaseSemaphore(sem->sema, 1, NULL);
}
int qemu_sem_timedwait(QemuSemaphore *sem, int ms)
{
- int rc = WaitForSingleObject(sem->sema, ms);
+ int rc;
+
+ assert(sem->initialized);
+ rc = WaitForSingleObject(sem->sema, ms);
if (rc == WAIT_OBJECT_0) {
return 0;
}
void qemu_sem_wait(QemuSemaphore *sem)
{
+ assert(sem->initialized);
if (WaitForSingleObject(sem->sema, INFINITE) != WAIT_OBJECT_0) {
error_exit(GetLastError(), __func__);
}
*
* Valid transitions:
* - free->set, when setting the event
- * - busy->set, when setting the event, followed by futex_wake
+ * - busy->set, when setting the event, followed by SetEvent
* - set->free, when resetting the event
* - free->busy, when waiting
*
/* Manual reset. */
ev->event = CreateEvent(NULL, TRUE, TRUE, NULL);
ev->value = (init ? EV_SET : EV_FREE);
+ ev->initialized = true;
}
void qemu_event_destroy(QemuEvent *ev)
{
+ assert(ev->initialized);
+ ev->initialized = false;
CloseHandle(ev->event);
}
void qemu_event_set(QemuEvent *ev)
{
- /* qemu_event_set has release semantics, but because it *loads*
+ assert(ev->initialized);
+
+ /*
+ * Pairs with both qemu_event_reset() and qemu_event_wait().
+ *
+ * qemu_event_set has release semantics, but because it *loads*
* ev->value we need a full memory barrier here.
*/
smp_mb();
- if (atomic_read(&ev->value) != EV_SET) {
- if (atomic_xchg(&ev->value, EV_SET) == EV_BUSY) {
+ if (qatomic_read(&ev->value) != EV_SET) {
+ int old = qatomic_xchg(&ev->value, EV_SET);
+
+ /* Pairs with memory barrier after ResetEvent. */
+ smp_mb__after_rmw();
+ if (old == EV_BUSY) {
/* There were waiters, wake them up. */
SetEvent(ev->event);
}
void qemu_event_reset(QemuEvent *ev)
{
- unsigned value;
+ assert(ev->initialized);
- value = atomic_read(&ev->value);
- smp_mb_acquire();
- if (value == EV_SET) {
- /* If there was a concurrent reset (or even reset+wait),
- * do nothing. Otherwise change EV_SET->EV_FREE.
- */
- atomic_or(&ev->value, EV_FREE);
- }
+ /*
+ * If there was a concurrent reset (or even reset+wait),
+ * do nothing. Otherwise change EV_SET->EV_FREE.
+ */
+ qatomic_or(&ev->value, EV_FREE);
+
+ /*
+ * Order reset before checking the condition in the caller.
+ * Pairs with the first memory barrier in qemu_event_set().
+ */
+ smp_mb__after_rmw();
}
void qemu_event_wait(QemuEvent *ev)
{
unsigned value;
- value = atomic_read(&ev->value);
- smp_mb_acquire();
+ assert(ev->initialized);
+
+ /*
+ * qemu_event_wait must synchronize with qemu_event_set even if it does
+ * not go down the slow path, so this load-acquire is needed that
+ * synchronizes with the first memory barrier in qemu_event_set().
+ *
+ * If we do go down the slow path, there is no requirement at all: we
+ * might miss a qemu_event_set() here but ultimately the memory barrier in
+ * qemu_futex_wait() will ensure the check is done correctly.
+ */
+ value = qatomic_load_acquire(&ev->value);
if (value != EV_SET) {
if (value == EV_FREE) {
- /* qemu_event_set is not yet going to call SetEvent, but we are
- * going to do another check for EV_SET below when setting EV_BUSY.
- * At that point it is safe to call WaitForSingleObject.
+ /*
+ * Here the underlying kernel event is reset, but qemu_event_set is
+ * not yet going to call SetEvent. However, there will be another
+ * check for EV_SET below when setting EV_BUSY. At that point it
+ * is safe to call WaitForSingleObject.
*/
ResetEvent(ev->event);
- /* Tell qemu_event_set that there are waiters. No need to retry
- * because there cannot be a concurent busy->free transition.
- * After the CAS, the event will be either set or busy.
+ /*
+ * It is not clear whether ResetEvent provides this barrier; kernel
+ * APIs (KeResetEvent/KeClearEvent) do not. Better safe than sorry!
+ */
+ smp_mb();
+
+ /*
+ * Leave the event reset and tell qemu_event_set that there are
+ * waiters. No need to retry, because there cannot be a concurrent
+ * busy->free transition. After the CAS, the event will be either
+ * set or busy.
*/
- if (atomic_cmpxchg(&ev->value, EV_FREE, EV_BUSY) == EV_SET) {
- value = EV_SET;
- } else {
- value = EV_BUSY;
+ if (qatomic_cmpxchg(&ev->value, EV_FREE, EV_BUSY) == EV_SET) {
+ return;
}
}
- if (value == EV_BUSY) {
- WaitForSingleObject(ev->event, INFINITE);
- }
+
+ /*
+ * ev->value is now EV_BUSY. Since we didn't observe EV_SET,
+ * qemu_event_set() must observe EV_BUSY and call SetEvent().
+ */
+ WaitForSingleObject(ev->event, INFINITE);
}
}
return ret;
}
+static bool set_thread_description(HANDLE h, const char *name)
+{
+ HRESULT hr;
+ g_autofree wchar_t *namew = NULL;
+
+ if (!load_set_thread_description()) {
+ return false;
+ }
+
+ namew = g_utf8_to_utf16(name, -1, NULL, NULL, NULL);
+ if (!namew) {
+ return false;
+ }
+
+ hr = SetThreadDescriptionFunc(h, namew);
+
+ return SUCCEEDED(hr);
+}
+
void qemu_thread_create(QemuThread *thread, const char *name,
void *(*start_routine)(void *),
void *arg, int mode)
if (!hThread) {
error_exit(GetLastError(), __func__);
}
+ if (name_threads && name && !set_thread_description(hThread, name)) {
+ fprintf(stderr, "qemu: failed to set thread description: %s\n", name);
+ }
CloseHandle(hThread);
+
thread->data = data;
}
+int qemu_thread_set_affinity(QemuThread *thread, unsigned long *host_cpus,
+ unsigned long nbits)
+{
+ return -ENOSYS;
+}
+
+int qemu_thread_get_affinity(QemuThread *thread, unsigned long **host_cpus,
+ unsigned long *nbits)
+{
+ return -ENOSYS;
+}
+
void qemu_thread_get_self(QemuThread *thread)
{
thread->data = qemu_thread_data;
EnterCriticalSection(&data->cs);
if (!data->exited) {
- handle = OpenThread(SYNCHRONIZE | THREAD_SUSPEND_RESUME, FALSE,
- thread->tid);
+ handle = OpenThread(SYNCHRONIZE | THREAD_SUSPEND_RESUME |
+ THREAD_SET_CONTEXT, FALSE, thread->tid);
} else {
handle = NULL;
}
projects / mirror_qemu.git / blobdiff