diff options
| -rw-r--r-- | Misc/NEWS | 2 | ||||
| -rw-r--r-- | PCbuild/pythoncore.vcxproj | 4 | ||||
| -rw-r--r-- | PCbuild/pythoncore.vcxproj.filters | 8 | ||||
| -rw-r--r-- | Python/ceval_gil.h | 218 | ||||
| -rw-r--r-- | Python/condvar.h | 353 | ||||
| -rw-r--r-- | Python/thread_nt.h | 104 |
6 files changed, 497 insertions, 192 deletions
@@ -26,6 +26,8 @@ Core and Builtins - Issue #14673: Add Eric Snow's sys.implementation implementation. +- Issue #15038: Optimize python Locks on Windows. + Library ------- diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj index e4d4c7d..29493e3 100644 --- a/PCbuild/pythoncore.vcxproj +++ b/PCbuild/pythoncore.vcxproj @@ -1,4 +1,4 @@ -<?xml version="1.0" encoding="utf-8"?> +<?xml version="1.0" encoding="utf-8"?> <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <ItemGroup Label="ProjectConfigurations"> <ProjectConfiguration Include="Debug|Win32"> @@ -481,6 +481,8 @@ <ClInclude Include="..\Parser\tokenizer.h" /> <ClInclude Include="..\PC\errmap.h" /> <ClInclude Include="..\PC\pyconfig.h" /> + <ClInclude Include="..\Python\ceval_gil.h" /> + <ClInclude Include="..\Python\condvar.h" /> <ClInclude Include="..\Python\importdl.h" /> <ClInclude Include="..\Python\thread_nt.h" /> </ItemGroup> diff --git a/PCbuild/pythoncore.vcxproj.filters b/PCbuild/pythoncore.vcxproj.filters index 1b46af8..09b4bb4 100644 --- a/PCbuild/pythoncore.vcxproj.filters +++ b/PCbuild/pythoncore.vcxproj.filters @@ -402,6 +402,13 @@ <ClInclude Include="..\Python\thread_nt.h"> <Filter>Python</Filter> </ClInclude> + <ClInclude Include="..\Include\namespaceobject.h" /> + <ClInclude Include="..\Python\condvar.h"> + <Filter>Python</Filter> + </ClInclude> + <ClInclude Include="..\Python\ceval_gil.h"> + <Filter>Python</Filter> + </ClInclude> </ItemGroup> <ItemGroup> <ClCompile Include="..\Modules\_bisectmodule.c"> @@ -908,6 +915,7 @@ <ClCompile Include="..\Modules\_winapi.c"> <Filter>PC</Filter> </ClCompile> + <ClCompile Include="..\Objects\namespaceobject.c" /> </ItemGroup> <ItemGroup> <ResourceCompile Include="..\PC\python_nt.rc"> diff --git a/Python/ceval_gil.h b/Python/ceval_gil.h index e7764f2..2702d5c 100644 --- a/Python/ceval_gil.h +++ b/Python/ceval_gil.h @@ -59,213 +59,49 @@ static unsigned long gil_interval = DEFAULT_INTERVAL; (Note: this mechanism is enabled with FORCE_SWITCHING above) */ -#ifndef _POSIX_THREADS -/* This means pthreads are not implemented in libc headers, hence the macro - not present in unistd.h. But they still can be implemented as an external - library (e.g. gnu pth in pthread emulation) */ -# ifdef HAVE_PTHREAD_H -# include <pthread.h> /* _POSIX_THREADS */ -# endif -#endif - - -#ifdef _POSIX_THREADS - -/* - * POSIX support - */ - -#include <pthread.h> - -#define ADD_MICROSECONDS(tv, interval) \ -do { \ - tv.tv_usec += (long) interval; \ - tv.tv_sec += tv.tv_usec / 1000000; \ - tv.tv_usec %= 1000000; \ -} while (0) - -/* We assume all modern POSIX systems have gettimeofday() */ -#ifdef GETTIMEOFDAY_NO_TZ -#define GETTIMEOFDAY(ptv) gettimeofday(ptv) -#else -#define GETTIMEOFDAY(ptv) gettimeofday(ptv, (struct timezone *)NULL) +#include "condvar.h" +#ifndef Py_HAVE_CONDVAR +#error You need either a POSIX-compatible or a Windows system! #endif -#define MUTEX_T pthread_mutex_t +#define MUTEX_T PyMUTEX_T #define MUTEX_INIT(mut) \ - if (pthread_mutex_init(&mut, NULL)) { \ - Py_FatalError("pthread_mutex_init(" #mut ") failed"); }; + if (PyMUTEX_INIT(&(mut))) { \ + Py_FatalError("PyMUTEX_INIT(" #mut ") failed"); }; #define MUTEX_FINI(mut) \ - if (pthread_mutex_destroy(&mut)) { \ - Py_FatalError("pthread_mutex_destroy(" #mut ") failed"); }; + if (PyMUTEX_FINI(&(mut))) { \ + Py_FatalError("PyMUTEX_FINI(" #mut ") failed"); }; #define MUTEX_LOCK(mut) \ - if (pthread_mutex_lock(&mut)) { \ - Py_FatalError("pthread_mutex_lock(" #mut ") failed"); }; + if (PyMUTEX_LOCK(&(mut))) { \ + Py_FatalError("PyMUTEX_LOCK(" #mut ") failed"); }; #define MUTEX_UNLOCK(mut) \ - if (pthread_mutex_unlock(&mut)) { \ - Py_FatalError("pthread_mutex_unlock(" #mut ") failed"); }; + if (PyMUTEX_UNLOCK(&(mut))) { \ + Py_FatalError("PyMUTEX_UNLOCK(" #mut ") failed"); }; -#define COND_T pthread_cond_t +#define COND_T PyCOND_T #define COND_INIT(cond) \ - if (pthread_cond_init(&cond, NULL)) { \ - Py_FatalError("pthread_cond_init(" #cond ") failed"); }; + if (PyCOND_INIT(&(cond))) { \ + Py_FatalError("PyCOND_INIT(" #cond ") failed"); }; #define COND_FINI(cond) \ - if (pthread_cond_destroy(&cond)) { \ - Py_FatalError("pthread_cond_destroy(" #cond ") failed"); }; + if (PyCOND_FINI(&(cond))) { \ + Py_FatalError("PyCOND_FINI(" #cond ") failed"); }; #define COND_SIGNAL(cond) \ - if (pthread_cond_signal(&cond)) { \ - Py_FatalError("pthread_cond_signal(" #cond ") failed"); }; + if (PyCOND_SIGNAL(&(cond))) { \ + Py_FatalError("PyCOND_SIGNAL(" #cond ") failed"); }; #define COND_WAIT(cond, mut) \ - if (pthread_cond_wait(&cond, &mut)) { \ - Py_FatalError("pthread_cond_wait(" #cond ") failed"); }; + if (PyCOND_WAIT(&(cond), &(mut))) { \ + Py_FatalError("PyCOND_WAIT(" #cond ") failed"); }; #define COND_TIMED_WAIT(cond, mut, microseconds, timeout_result) \ { \ - int r; \ - struct timespec ts; \ - struct timeval deadline; \ - \ - GETTIMEOFDAY(&deadline); \ - ADD_MICROSECONDS(deadline, microseconds); \ - ts.tv_sec = deadline.tv_sec; \ - ts.tv_nsec = deadline.tv_usec * 1000; \ - \ - r = pthread_cond_timedwait(&cond, &mut, &ts); \ - if (r == ETIMEDOUT) \ + int r = PyCOND_TIMEDWAIT(&(cond), &(mut), (microseconds)); \ + if (r < 0) \ + Py_FatalError("PyCOND_WAIT(" #cond ") failed"); \ + if (r) /* 1 == timeout, 2 == impl. can't say, so assume timeout */ \ timeout_result = 1; \ - else if (r) \ - Py_FatalError("pthread_cond_timedwait(" #cond ") failed"); \ else \ timeout_result = 0; \ } \ -#elif defined(NT_THREADS) - -/* - * Windows (2000 and later, as well as (hopefully) CE) support - */ - -#include <windows.h> - -#define MUTEX_T CRITICAL_SECTION -#define MUTEX_INIT(mut) do { \ - if (!(InitializeCriticalSectionAndSpinCount(&(mut), 4000))) \ - Py_FatalError("CreateMutex(" #mut ") failed"); \ -} while (0) -#define MUTEX_FINI(mut) \ - DeleteCriticalSection(&(mut)) -#define MUTEX_LOCK(mut) \ - EnterCriticalSection(&(mut)) -#define MUTEX_UNLOCK(mut) \ - LeaveCriticalSection(&(mut)) - -/* We emulate condition variables with a semaphore. - We use a Semaphore rather than an auto-reset event, because although - an auto-resent event might appear to solve the lost-wakeup bug (race - condition between releasing the outer lock and waiting) because it - maintains state even though a wait hasn't happened, there is still - a lost wakeup problem if more than one thread are interrupted in the - critical place. A semaphore solves that. - Because it is ok to signal a condition variable with no one - waiting, we need to keep track of the number of - waiting threads. Otherwise, the semaphore's state could rise - without bound. - - Generic emulations of the pthread_cond_* API using - Win32 functions can be found on the Web. - The following read can be edificating (or not): - http://www.cse.wustl.edu/~schmidt/win32-cv-1.html -*/ -typedef struct COND_T -{ - HANDLE sem; /* the semaphore */ - int n_waiting; /* how many are unreleased */ -} COND_T; - -__inline static void _cond_init(COND_T *cond) -{ - /* A semaphore with a large max value, The positive value - * is only needed to catch those "lost wakeup" events and - * race conditions when a timed wait elapses. - */ - if (!(cond->sem = CreateSemaphore(NULL, 0, 1000, NULL))) - Py_FatalError("CreateSemaphore() failed"); - cond->n_waiting = 0; -} - -__inline static void _cond_fini(COND_T *cond) -{ - BOOL ok = CloseHandle(cond->sem); - if (!ok) - Py_FatalError("CloseHandle() failed"); -} - -__inline static void _cond_wait(COND_T *cond, MUTEX_T *mut) -{ - ++cond->n_waiting; - MUTEX_UNLOCK(*mut); - /* "lost wakeup bug" would occur if the caller were interrupted here, - * but we are safe because we are using a semaphore wich has an internal - * count. - */ - if (WaitForSingleObject(cond->sem, INFINITE) == WAIT_FAILED) - Py_FatalError("WaitForSingleObject() failed"); - MUTEX_LOCK(*mut); -} - -__inline static int _cond_timed_wait(COND_T *cond, MUTEX_T *mut, - int us) -{ - DWORD r; - ++cond->n_waiting; - MUTEX_UNLOCK(*mut); - r = WaitForSingleObject(cond->sem, us / 1000); - if (r == WAIT_FAILED) - Py_FatalError("WaitForSingleObject() failed"); - MUTEX_LOCK(*mut); - if (r == WAIT_TIMEOUT) - --cond->n_waiting; - /* Here we have a benign race condition with _cond_signal. If the - * wait operation has timed out, but before we can acquire the - * mutex again to decrement n_waiting, a thread holding the mutex - * still sees a positive n_waiting value and may call - * ReleaseSemaphore and decrement n_waiting. - * This will cause n_waiting to be decremented twice. - * This is benign, though, because ReleaseSemaphore will also have - * been called, leaving the semaphore state positive. We may - * thus end up with semaphore in state 1, and n_waiting == -1, and - * the next time someone calls _cond_wait(), that thread will - * pass right through, decrementing the semaphore state and - * incrementing n_waiting, thus correcting the extra _cond_signal. - */ - return r == WAIT_TIMEOUT; -} - -__inline static void _cond_signal(COND_T *cond) { - /* NOTE: This must be called with the mutex held */ - if (cond->n_waiting > 0) { - if (!ReleaseSemaphore(cond->sem, 1, NULL)) - Py_FatalError("ReleaseSemaphore() failed"); - --cond->n_waiting; - } -} - -#define COND_INIT(cond) \ - _cond_init(&(cond)) -#define COND_FINI(cond) \ - _cond_fini(&(cond)) -#define COND_SIGNAL(cond) \ - _cond_signal(&(cond)) -#define COND_WAIT(cond, mut) \ - _cond_wait(&(cond), &(mut)) -#define COND_TIMED_WAIT(cond, mut, us, timeout_result) do { \ - (timeout_result) = _cond_timed_wait(&(cond), &(mut), us); \ -} while (0) - -#else - -#error You need either a POSIX-compatible or a Windows system! - -#endif /* _POSIX_THREADS, NT_THREADS */ /* Whether the GIL is already taken (-1 if uninitialized). This is atomic @@ -356,13 +192,13 @@ static void drop_gil(PyThreadState *tstate) MUTEX_LOCK(switch_mutex); /* Not switched yet => wait */ if (_Py_atomic_load_relaxed(&gil_last_holder) == tstate) { - RESET_GIL_DROP_REQUEST(); + RESET_GIL_DROP_REQUEST(); /* NOTE: if COND_WAIT does not atomically start waiting when releasing the mutex, another thread can run through, take the GIL and drop it again, and reset the condition before we even had a chance to wait for it. */ COND_WAIT(switch_cond, switch_mutex); - } + } MUTEX_UNLOCK(switch_mutex); } #endif diff --git a/Python/condvar.h b/Python/condvar.h new file mode 100644 index 0000000..8d3c595 --- /dev/null +++ b/Python/condvar.h @@ -0,0 +1,353 @@ +/* + * Portable condition variable support for windows and pthreads. + * Everything is inline, this header can be included where needed. + * + * APIs generally return 0 on success and non-zero on error, + * and the caller needs to use its platform's error mechanism to + * discover the error (errno, or GetLastError()) + * + * Note that some implementations cannot distinguish between a + * condition variable wait time-out and successful wait. Most often + * the difference is moot anyway since the wait condition must be + * re-checked. + * PyCOND_TIMEDWAIT, in addition to returning negative on error, + * thus returns 0 on regular success, 1 on timeout + * or 2 if it can't tell. + */ + +#ifndef _CONDVAR_H_ +#define _CONDVAR_H_ + +#include "Python.h" + +#ifndef _POSIX_THREADS +/* This means pthreads are not implemented in libc headers, hence the macro + not present in unistd.h. But they still can be implemented as an external + library (e.g. gnu pth in pthread emulation) */ +# ifdef HAVE_PTHREAD_H +# include <pthread.h> /* _POSIX_THREADS */ +# endif +#endif + +#ifdef _POSIX_THREADS +/* + * POSIX support + */ +#define Py_HAVE_CONDVAR + +#include <pthread.h> + +#define PyCOND_ADD_MICROSECONDS(tv, interval) \ +do { \ + tv.tv_usec += (long) interval; \ + tv.tv_sec += tv.tv_usec / 1000000; \ + tv.tv_usec %= 1000000; \ +} while (0) + +/* We assume all modern POSIX systems have gettimeofday() */ +#ifdef GETTIMEOFDAY_NO_TZ +#define PyCOND_GETTIMEOFDAY(ptv) gettimeofday(ptv) +#else +#define PyCOND_GETTIMEOFDAY(ptv) gettimeofday(ptv, (struct timezone *)NULL) +#endif + +/* The following functions return 0 on success, nonzero on error */ +#define PyMUTEX_T pthread_mutex_t +#define PyMUTEX_INIT(mut) pthread_mutex_init((mut), NULL) +#define PyMUTEX_FINI(mut) pthread_mutex_destroy(mut) +#define PyMUTEX_LOCK(mut) pthread_mutex_lock(mut) +#define PyMUTEX_UNLOCK(mut) pthread_mutex_unlock(mut) + +#define PyCOND_T pthread_cond_t +#define PyCOND_INIT(cond) pthread_cond_init((cond), NULL) +#define PyCOND_FINI(cond) pthread_cond_destroy(cond) +#define PyCOND_SIGNAL(cond) pthread_cond_signal(cond) +#define PyCOND_BROADCAST(cond) pthread_cond_broadcast(cond) +#define PyCOND_WAIT(cond, mut) pthread_cond_wait((cond), (mut)) + +/* return 0 for success, 1 on timeout, -1 on error */ +Py_LOCAL_INLINE(int) +PyCOND_TIMEDWAIT(PyCOND_T *cond, PyMUTEX_T *mut, long us) +{ + int r; + struct timespec ts; + struct timeval deadline; + + PyCOND_GETTIMEOFDAY(&deadline); + PyCOND_ADD_MICROSECONDS(deadline, us); + ts.tv_sec = deadline.tv_sec; + ts.tv_nsec = deadline.tv_usec * 1000; + + r = pthread_cond_timedwait((cond), (mut), &ts); + if (r == ETIMEDOUT) + return 1; + else if (r) + return -1; + else + return 0; +} + +#elif defined(NT_THREADS) +/* + * Windows (XP, 2003 server and later, as well as (hopefully) CE) support + * + * Emulated condition variables ones that work with XP and later, plus + * example native support on VISTA and onwards. + */ +#define Py_HAVE_CONDVAR + + +/* include windows if it hasn't been done before */ +#define WIN32_LEAN_AND_MEAN +#include <windows.h> + +/* options */ +/* non-emulated condition variables are provided for those that want + * to target Windows Vista. Modify this macro to enable them. + */ +#ifndef _PY_EMULATED_WIN_CV +#define _PY_EMULATED_WIN_CV 1 /* use emulated condition variables */ +#endif + +/* fall back to emulation if not targeting Vista */ +#if !defined NTDDI_VISTA || NTDDI_VERSION < NTDDI_VISTA +#undef _PY_EMULATED_WIN_CV +#define _PY_EMULATED_WIN_CV 1 +#endif + + +#if _PY_EMULATED_WIN_CV + +/* The mutex is a CriticalSection object and + The condition variables is emulated with the help of a semaphore. + Semaphores are available on Windows XP (2003 server) and later. + We use a Semaphore rather than an auto-reset event, because although + an auto-resent event might appear to solve the lost-wakeup bug (race + condition between releasing the outer lock and waiting) because it + maintains state even though a wait hasn't happened, there is still + a lost wakeup problem if more than one thread are interrupted in the + critical place. A semaphore solves that, because its state is counted, + not Boolean. + Because it is ok to signal a condition variable with no one + waiting, we need to keep track of the number of + waiting threads. Otherwise, the semaphore's state could rise + without bound. This also helps reduce the number of "spurious wakeups" + that would otherwise happen. + + Generic emulations of the pthread_cond_* API using + earlier Win32 functions can be found on the Web. + The following read can be edificating (or not): + http://www.cse.wustl.edu/~schmidt/win32-cv-1.html +*/ + +typedef CRITICAL_SECTION PyMUTEX_T; + +Py_LOCAL_INLINE(int) +PyMUTEX_INIT(PyMUTEX_T *cs) +{ + InitializeCriticalSection(cs); + return 0; +} + +Py_LOCAL_INLINE(int) +PyMUTEX_FINI(PyMUTEX_T *cs) +{ + DeleteCriticalSection(cs); + return 0; +} + +Py_LOCAL_INLINE(int) +PyMUTEX_LOCK(PyMUTEX_T *cs) +{ + EnterCriticalSection(cs); + return 0; +} + +Py_LOCAL_INLINE(int) +PyMUTEX_UNLOCK(PyMUTEX_T *cs) +{ + LeaveCriticalSection(cs); + return 0; +} + +/* The ConditionVariable object. From XP onwards it is easily emulated with + * a Semaphore + */ + +typedef struct _PyCOND_T +{ + HANDLE sem; + int waiting; +} PyCOND_T; + +Py_LOCAL_INLINE(int) +PyCOND_INIT(PyCOND_T *cv) +{ + /* A semaphore with a "large" max value, The positive value + * is only needed to catch those "lost wakeup" events and + * race conditions when a timed wait elapses. + */ + cv->sem = CreateSemaphore(NULL, 0, 100000, NULL); + if (cv->sem==NULL) + return -1; + cv->waiting = 0; + return 0; +} + +Py_LOCAL_INLINE(int) +PyCOND_FINI(PyCOND_T *cv) +{ + return CloseHandle(cv->sem) ? 0 : -1; +} + +/* this implementation can detect a timeout. Returns 1 on timeout, + * 0 otherwise (and -1 on error) + */ +Py_LOCAL_INLINE(int) +_PyCOND_WAIT_MS(PyCOND_T *cv, PyMUTEX_T *cs, DWORD ms) +{ + DWORD wait; + cv->waiting++; + PyMUTEX_UNLOCK(cs); + /* "lost wakeup bug" would occur if the caller were interrupted here, + * but we are safe because we are using a semaphore wich has an internal + * count. + */ + wait = WaitForSingleObject(cv->sem, ms); + PyMUTEX_LOCK(cs); + if (wait != WAIT_OBJECT_0) + --cv->waiting; + /* Here we have a benign race condition with PyCOND_SIGNAL. + * When failure occurs or timeout, it is possible that + * PyCOND_SIGNAL also decrements this value + * and signals releases the mutex. This is benign because it + * just means an extra spurious wakeup for a waiting thread. + */ + + if (wait == WAIT_FAILED) + return -1; + /* return 0 on success, 1 on timeout */ + return wait != WAIT_OBJECT_0; +} + +Py_LOCAL_INLINE(int) +PyCOND_WAIT(PyCOND_T *cv, PyMUTEX_T *cs) +{ + int result = _PyCOND_WAIT_MS(cv, cs, INFINITE); + return result >= 0 ? 0 : result; +} + +Py_LOCAL_INLINE(int) +PyCOND_TIMEDWAIT(PyCOND_T *cv, PyMUTEX_T *cs, long us) +{ + return _PyCOND_WAIT_MS(cv, cs, us/1000); +} + +Py_LOCAL_INLINE(int) +PyCOND_SIGNAL(PyCOND_T *cv) +{ + if (cv->waiting) { + /* notifying thread decreases the cv->waiting count so that + * a delay between notify and wakeup doesn't cause a number + * of extra ReleaseSemaphore calls + */ + cv->waiting--; + return ReleaseSemaphore(cv->sem, 1, NULL) ? 0 : -1; + } + return 0; +} + +Py_LOCAL_INLINE(int) +PyCOND_BROADCAST(PyCOND_T *cv) +{ + if (cv->waiting) { + return ReleaseSemaphore(cv->sem, cv->waiting, NULL) ? 0 : -1; + cv->waiting = 0; + } + return 0; +} + +#else + +/* Use native Win7 primitives if build target is Win7 or higher */ + +/* SRWLOCK is faster and better than CriticalSection */ +typedef SRWLOCK PyMUTEX_T; + +Py_LOCAL_INLINE(int) +PyMUTEX_INIT(PyMUTEX_T *cs) +{ + InitializeSRWLock(cs); + return 0; +} + +Py_LOCAL_INLINE(int) +PyMUTEX_FINI(PyMUTEX_T *cs) +{ + return 0; +} + +Py_LOCAL_INLINE(int) +PyMUTEX_LOCK(PyMUTEX_T *cs) +{ + AcquireSRWLockExclusive(cs); + return 0; +} + +Py_LOCAL_INLINE(int) +PyMUTEX_UNLOCK(PyMUTEX_T *cs) +{ + ReleaseSRWLockExclusive(cs); + return 0; +} + + +typedef CONDITION_VARIABLE PyCOND_T; + +Py_LOCAL_INLINE(int) +PyCOND_INIT(PyCOND_T *cv) +{ + InitializeConditionVariable(cv); + return 0; +} +Py_LOCAL_INLINE(int) +PyCOND_FINI(PyCOND_T *cv) +{ + return 0; +} + +Py_LOCAL_INLINE(int) +PyCOND_WAIT(PyCOND_T *cv, PyMUTEX_T *cs) +{ + return SleepConditionVariableSRW(cv, cs, INFINITE, 0) ? 0 : -1; +} + +/* This implementation makes no distinction about timeouts. Signal + * 2 to indicate that we don't know. + */ +Py_LOCAL_INLINE(int) +PyCOND_TIMEDWAIT(PyCOND_T *cv, PyMUTEX_T *cs, long us) +{ + return SleepConditionVariableSRW(cv, cs, us/1000, 0) ? 2 : -1; +} + +Py_LOCAL_INLINE(int) +PyCOND_SIGNAL(PyCOND_T *cv) +{ + WakeConditionVariable(cv); + return 0; +} + +Py_LOCAL_INLINE(int) +PyCOND_BROADCAST(PyCOND_T *cv) +{ + WakeAllConditionVariable(cv); + return 0; +} + + +#endif /* _PY_EMULATED_WIN_CV */ + +#endif /* _POSIX_THREADS, NT_THREADS */ + +#endif /* _CONDVAR_H_ */ diff --git a/Python/thread_nt.h b/Python/thread_nt.h index d1bb0e5..938bf1e 100644 --- a/Python/thread_nt.h +++ b/Python/thread_nt.h @@ -9,6 +9,109 @@ #include <process.h> #endif +/* options */ +#ifndef _PY_USE_CV_LOCKS +#define _PY_USE_CV_LOCKS 1 /* use locks based on cond vars */ +#endif + +/* Now, define a non-recursive mutex using either condition variables + * and critical sections (fast) or using operating system mutexes + * (slow) + */ + +#if _PY_USE_CV_LOCKS + +#include "condvar.h" + +typedef struct _NRMUTEX +{ + PyMUTEX_T cs; + PyCOND_T cv; + int locked; +} NRMUTEX; +typedef NRMUTEX *PNRMUTEX; + +PNRMUTEX +AllocNonRecursiveMutex() +{ + PNRMUTEX m = (PNRMUTEX)malloc(sizeof(NRMUTEX)); + if (!m) + return NULL; + if (PyCOND_INIT(&m->cv)) + goto fail; + if (PyMUTEX_INIT(&m->cs)) { + PyCOND_FINI(&m->cv); + goto fail; + } + m->locked = 0; + return m; +fail: + free(m); + return NULL; +} + +VOID +FreeNonRecursiveMutex(PNRMUTEX mutex) +{ + if (mutex) { + PyCOND_FINI(&mutex->cv); + PyMUTEX_FINI(&mutex->cs); + free(mutex); + } +} + +DWORD +EnterNonRecursiveMutex(PNRMUTEX mutex, DWORD milliseconds) +{ + DWORD result = WAIT_OBJECT_0; + if (PyMUTEX_LOCK(&mutex->cs)) + return WAIT_FAILED; + if (milliseconds == INFINITE) { + while (mutex->locked) { + if (PyCOND_WAIT(&mutex->cv, &mutex->cs)) { + result = WAIT_FAILED; + break; + } + } + } else if (milliseconds != 0) { + /* wait at least until the target */ + DWORD now, target = GetTickCount() + milliseconds; + while (mutex->locked) { + if (PyCOND_TIMEDWAIT(&mutex->cv, &mutex->cs, milliseconds*1000) < 0) { + result = WAIT_FAILED; + break; + } + now = GetTickCount(); + if (target <= now) + break; + milliseconds = target-now; + } + } + if (!mutex->locked) { + mutex->locked = 1; + result = WAIT_OBJECT_0; + } else if (result == WAIT_OBJECT_0) + result = WAIT_TIMEOUT; + /* else, it is WAIT_FAILED */ + PyMUTEX_UNLOCK(&mutex->cs); /* must ignore result here */ + return result; +} + +BOOL +LeaveNonRecursiveMutex(PNRMUTEX mutex) +{ + BOOL result; + if (PyMUTEX_LOCK(&mutex->cs)) + return FALSE; + mutex->locked = 0; + result = PyCOND_SIGNAL(&mutex->cv); + result &= PyMUTEX_UNLOCK(&mutex->cs); + return result; +} + +#else /* if ! _PY_USE_CV_LOCKS */ + +/* NR-locks based on a kernel mutex */ #define PNRMUTEX HANDLE PNRMUTEX @@ -35,6 +138,7 @@ LeaveNonRecursiveMutex(PNRMUTEX mutex) { return ReleaseSemaphore(mutex, 1, NULL); } +#endif /* _PY_USE_CV_LOCKS */ long PyThread_get_thread_ident(void); |