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rt: lock_and_signal fixes #1869

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Merged
merged 3 commits into from
Feb 20, 2012
Merged

rt: lock_and_signal fixes #1869

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159dfd7
rt: Delete Windows CRITICAL_SECTION in dtor
cpeterso Feb 20, 2012
9f49293
rt: Initialize Windows CRITICAL_SECTION with non-zero spin count
cpeterso Feb 20, 2012
fed81c2
rt: Add some lock_and_signal assertions
cpeterso Feb 20, 2012
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19 changes: 18 additions & 1 deletion src/rt/sync/lock_and_signal.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -19,7 +19,18 @@ lock_and_signal::lock_and_signal()
: _holding_thread(INVALID_THREAD)
{
_event = CreateEvent(NULL, FALSE, FALSE, NULL);
InitializeCriticalSection(&_cs);

// If a CRITICAL_SECTION is not initialized with a spin count, it will
// default to 0, even on multi-processor systems. MSDN suggests using
// 4000. On single-processor systems, the spin count parameter is ignored
// and the critical section's spin count defaults to 0.
const DWORD SPIN_COUNT = 4000;
CHECKED(!InitializeCriticalSectionAndSpinCount(&_cs, SPIN_COUNT));

// TODO? Consider checking GetProcAddress("InitializeCriticalSectionEx")
// so Windows >= Vista we can use CRITICAL_SECTION_NO_DEBUG_INFO to avoid
// allocating CRITICAL_SECTION debug info that is never released. See:
// http://stackoverflow.com/questions/804848/critical-sections-leaking-memory-on-vista-win2008#889853
}

#else
Expand All @@ -32,15 +43,18 @@ lock_and_signal::lock_and_signal()
#endif

lock_and_signal::~lock_and_signal() {
assert(_holding_thread == INVALID_THREAD);
#if defined(__WIN32__)
CloseHandle(_event);
DeleteCriticalSection(&_cs);
#else
CHECKED(pthread_cond_destroy(&_cond));
CHECKED(pthread_mutex_destroy(&_mutex));
#endif
}

void lock_and_signal::lock() {
assert(!lock_held_by_current_thread());
#if defined(__WIN32__)
EnterCriticalSection(&_cs);
_holding_thread = GetCurrentThreadId();
Expand All @@ -51,6 +65,7 @@ void lock_and_signal::lock() {
}

void lock_and_signal::unlock() {
assert(lock_held_by_current_thread());
_holding_thread = INVALID_THREAD;
#if defined(__WIN32__)
LeaveCriticalSection(&_cs);
Expand All @@ -69,9 +84,11 @@ void lock_and_signal::wait() {
LeaveCriticalSection(&_cs);
WaitForSingleObject(_event, INFINITE);
EnterCriticalSection(&_cs);
assert(_holding_thread == INVALID_THREAD);
_holding_thread = GetCurrentThreadId();
#else
CHECKED(pthread_cond_wait(&_cond, &_mutex));
assert(_holding_thread == INVALID_THREAD);
_holding_thread = pthread_self();
#endif
}
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