[3.6] bpo-30765: Avoid blocking when PyThread_acquire_lock() is asked… · python/cpython@55ab604 (original) (raw)

`@@ -466,61 +466,66 @@ PyLockStatus

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`PyThread_acquire_lock_timed(PyThread_type_lock lock, PY_TIMEOUT_T microseconds,

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`int intr_flag)

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PyLockStatus success;

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PyLockStatus success = PY_LOCK_FAILURE;

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`pthread_lock *thelock = (pthread_lock *)lock;

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`int status, error = 0;

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`dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) called\n",

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`lock, microseconds, intr_flag));

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status = pthread_mutex_lock( &thelock->mut );

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CHECK_STATUS_PTHREAD("pthread_mutex_lock[1]");

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-

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if (thelock->locked == 0) {

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success = PY_LOCK_ACQUIRED;

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} else if (microseconds == 0) {

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success = PY_LOCK_FAILURE;

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} else {

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struct timespec ts;

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if (microseconds > 0)

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MICROSECONDS_TO_TIMESPEC(microseconds, ts);

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/* continue trying until we get the lock */

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-

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/* mut must be locked by me -- part of the condition

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protocol */

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success = PY_LOCK_FAILURE;

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while (success == PY_LOCK_FAILURE) {

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if (microseconds > 0) {

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status = pthread_cond_timedwait(

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&thelock->lock_released,

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&thelock->mut, &ts);

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if (status == ETIMEDOUT)

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if (microseconds == 0) {

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status = pthread_mutex_trylock( &thelock->mut );

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if (status != EBUSY)

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CHECK_STATUS_PTHREAD("pthread_mutex_trylock[1]");

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}

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else {

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status = pthread_mutex_lock( &thelock->mut );

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CHECK_STATUS_PTHREAD("pthread_mutex_lock[1]");

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}

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if (status == 0) {

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if (thelock->locked == 0) {

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success = PY_LOCK_ACQUIRED;

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}

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else if (microseconds != 0) {

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struct timespec ts;

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if (microseconds > 0)

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MICROSECONDS_TO_TIMESPEC(microseconds, ts);

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/* continue trying until we get the lock */

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+

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/* mut must be locked by me -- part of the condition

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protocol */

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while (success == PY_LOCK_FAILURE) {

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if (microseconds > 0) {

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status = pthread_cond_timedwait(

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&thelock->lock_released,

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&thelock->mut, &ts);

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if (status == ETIMEDOUT)

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break;

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CHECK_STATUS_PTHREAD("pthread_cond_timed_wait");

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}

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else {

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status = pthread_cond_wait(

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&thelock->lock_released,

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&thelock->mut);

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CHECK_STATUS_PTHREAD("pthread_cond_wait");

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}

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+

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if (intr_flag && status == 0 && thelock->locked) {

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/* We were woken up, but didn't get the lock. We probably received

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a signal. Return PY_LOCK_INTR to allow the caller to handle

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it and retry. */

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success = PY_LOCK_INTR;

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`break;

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CHECK_STATUS_PTHREAD("pthread_cond_timed_wait");

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}

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else {

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status = pthread_cond_wait(

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&thelock->lock_released,

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&thelock->mut);

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CHECK_STATUS_PTHREAD("pthread_cond_wait");

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}

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-

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if (intr_flag && status == 0 && thelock->locked) {

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/* We were woken up, but didn't get the lock. We probably received

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a signal. Return PY_LOCK_INTR to allow the caller to handle

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it and retry. */

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success = PY_LOCK_INTR;

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break;

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} else if (status == 0 && !thelock->locked) {

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success = PY_LOCK_ACQUIRED;

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} else {

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success = PY_LOCK_FAILURE;

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}

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else if (status == 0 && !thelock->locked) {

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success = PY_LOCK_ACQUIRED;

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}

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` }

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` }

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if (success == PY_LOCK_ACQUIRED) thelock->locked = 1;

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status = pthread_mutex_unlock( &thelock->mut );

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CHECK_STATUS_PTHREAD("pthread_mutex_unlock[1]");

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` }

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if (success == PY_LOCK_ACQUIRED) thelock->locked = 1;

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status = pthread_mutex_unlock( &thelock->mut );

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CHECK_STATUS_PTHREAD("pthread_mutex_unlock[1]");

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`if (error) success = PY_LOCK_FAILURE;

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`dprintf(("PyThread_acquire_lock_timed(%p, %lld, %d) -> %d\n",