diff options
Diffstat (limited to 'src/corelib/thread')
-rw-r--r-- | src/corelib/thread/qsemaphore.cpp | 46 | ||||
-rw-r--r-- | src/corelib/thread/qthreadpool.cpp | 1 |
2 files changed, 18 insertions, 29 deletions
diff --git a/src/corelib/thread/qsemaphore.cpp b/src/corelib/thread/qsemaphore.cpp index d4fb756b94..1d01fc1b28 100644 --- a/src/corelib/thread/qsemaphore.cpp +++ b/src/corelib/thread/qsemaphore.cpp @@ -357,47 +357,31 @@ void QSemaphore::release(int n) quintptr prevValue = u.fetchAndAddRelease(nn); if (futexNeedsWake(prevValue)) { #ifdef FUTEX_OP - if (!futexHasWaiterCount) { - /* - On 32-bit systems, all waiters are waiting on the same address, - so we'll wake them all and ask the kernel to clear the high bit. - - atomic { - int oldval = u; - u = oldval & ~(1 << 31); - futexWake(u, INT_MAX); - if (oldval == 0) // impossible condition - futexWake(u, INT_MAX); - } - */ - quint32 op = FUTEX_OP_ANDN | FUTEX_OP_OPARG_SHIFT; - quint32 oparg = 31; - quint32 cmp = FUTEX_OP_CMP_EQ; - quint32 cmparg = 0; - futexWakeOp(u, INT_MAX, INT_MAX, u, FUTEX_OP(op, oparg, cmp, cmparg)); - } else { + if (futexHasWaiterCount) { /* On 64-bit systems, the single-token waiters wait on the low half and the multi-token waiters wait on the upper half. So we ask the kernel to wake up n single-token waiters and all multi-token - waiters (if any), then clear the multi-token wait bit. + waiters (if any), and clear the multi-token wait bit. atomic { int oldval = *upper; - *upper = oldval & ~(1 << 31); + *upper = oldval | 0; futexWake(lower, n); - if (oldval < 0) // sign bit set + if (oldval != 0) // always true futexWake(upper, INT_MAX); } */ - quint32 op = FUTEX_OP_ANDN | FUTEX_OP_OPARG_SHIFT; - quint32 oparg = 31; - quint32 cmp = FUTEX_OP_CMP_LT; + quint32 op = FUTEX_OP_OR; + quint32 oparg = 0; + quint32 cmp = FUTEX_OP_CMP_NE; quint32 cmparg = 0; + u.fetchAndAndRelease(futexNeedsWakeAllBit - 1); futexWakeOp(*futexLow32(&u), n, INT_MAX, *futexHigh32(&u), FUTEX_OP(op, oparg, cmp, cmparg)); + return; } -#else - // Unset the bit and wake everyone. There are two possibibilies +#endif + // Unset the bit and wake everyone. There are two possibilities // under which a thread can set the bit between the AND and the // futexWake: // 1) it did see the new counter value, but it wasn't enough for @@ -405,8 +389,12 @@ void QSemaphore::release(int n) // 2) it did not see the new counter value, in which case its // futexWait will fail. u.fetchAndAndRelease(futexNeedsWakeAllBit - 1); - futexWakeAll(u); -#endif + if (futexHasWaiterCount) { + futexWakeAll(*futexLow32(&u)); + futexWakeAll(*futexHigh32(&u)); + } else { + futexWakeAll(u); + } } return; } diff --git a/src/corelib/thread/qthreadpool.cpp b/src/corelib/thread/qthreadpool.cpp index 93d0ffe695..7d98eea4ce 100644 --- a/src/corelib/thread/qthreadpool.cpp +++ b/src/corelib/thread/qthreadpool.cpp @@ -788,6 +788,7 @@ bool QThreadPool::contains(const QThread *thread) const const QThreadPoolThread *poolThread = qobject_cast<const QThreadPoolThread *>(thread); if (!poolThread) return false; + QMutexLocker locker(&d->mutex); return d->allThreads.contains(const_cast<QThreadPoolThread *>(poolThread)); } |