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8211176: Initialize ObjectMonitor eagerly

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Reviewed-by: dholmes, adinn, redestad
This commit is contained in:
Mikael Vidstedt 2018-09-28 14:11:21 -07:00
parent 7ef28cb2bc
commit f4b9613346
2 changed files with 14 additions and 30 deletions
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43
src/hotspot/share/runtime/objectMonitor.cpp
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@ -110,7 +110,7 @@ static int Knob_Poverty = 1000;
static int Knob_FixedSpin = 0; static int Knob_FixedSpin = 0;
static int Knob_PreSpin = 10; // 20-100 likely better static int Knob_PreSpin = 10; // 20-100 likely better
static volatile int InitDone = 0; DEBUG_ONLY(static volatile bool InitDone = false;)
// ----------------------------------------------------------------------------- // -----------------------------------------------------------------------------
// Theory of operations -- Monitors lists, thread residency, etc: // Theory of operations -- Monitors lists, thread residency, etc:
@ -428,7 +428,7 @@ void ObjectMonitor::EnterI(TRAPS) {
return; return;
} }
DeferredInitialize(); assert(InitDone, "Unexpectedly not initialized");
// We try one round of spinning *before* enqueueing Self. // We try one round of spinning *before* enqueueing Self.
// //
@ -1102,7 +1102,7 @@ intptr_t ObjectMonitor::complete_exit(TRAPS) {
assert(Self->is_Java_thread(), "Must be Java thread!"); assert(Self->is_Java_thread(), "Must be Java thread!");
JavaThread *jt = (JavaThread *)THREAD; JavaThread *jt = (JavaThread *)THREAD;
DeferredInitialize(); assert(InitDone, "Unexpectedly not initialized");
if (THREAD != _owner) { if (THREAD != _owner) {
if (THREAD->is_lock_owned ((address)_owner)) { if (THREAD->is_lock_owned ((address)_owner)) {
@ -1186,7 +1186,7 @@ void ObjectMonitor::wait(jlong millis, bool interruptible, TRAPS) {
assert(Self->is_Java_thread(), "Must be Java thread!"); assert(Self->is_Java_thread(), "Must be Java thread!");
JavaThread *jt = (JavaThread *)THREAD; JavaThread *jt = (JavaThread *)THREAD;
DeferredInitialize(); assert(InitDone, "Unexpectedly not initialized");
// Throw IMSX or IEX. // Throw IMSX or IEX.
CHECK_OWNER(); CHECK_OWNER();
@ -1888,9 +1888,14 @@ PerfLongVariable * ObjectMonitor::_sync_MonExtant = NULL;
// be protected - like so many things - by the MonitorCache_lock. // be protected - like so many things - by the MonitorCache_lock.
void ObjectMonitor::Initialize() { void ObjectMonitor::Initialize() {
static int InitializationCompleted = 0; assert(!InitDone, "invariant");
assert(InitializationCompleted == 0, "invariant");
InitializationCompleted = 1; if (!os::is_MP()) {
Knob_SpinLimit = 0;
Knob_PreSpin = 0;
Knob_FixedSpin = -1;
}
if (UsePerfData) { if (UsePerfData) {
EXCEPTION_MARK; EXCEPTION_MARK;
#define NEWPERFCOUNTER(n) \ #define NEWPERFCOUNTER(n) \
@ -1913,26 +1918,6 @@ void ObjectMonitor::Initialize() {
#undef NEWPERFCOUNTER #undef NEWPERFCOUNTER
#undef NEWPERFVARIABLE #undef NEWPERFVARIABLE
} }
DEBUG_ONLY(InitDone = true;)
} }
void ObjectMonitor::DeferredInitialize() {
if (InitDone > 0) return;
if (Atomic::cmpxchg (-1, &InitDone, 0) != 0) {
while (InitDone != 1) /* empty */;
return;
}
// One-shot global initialization ...
// The initialization is idempotent, so we don't need locks.
// In the future consider doing this via os::init_2().
if (!os::is_MP()) {
Knob_SpinLimit = 0;
Knob_PreSpin = 0;
Knob_FixedSpin = -1;
}
OrderAccess::fence();
InitDone = 1;
}

1
src/hotspot/share/runtime/objectMonitor.hpp
View File

@ -302,7 +302,6 @@ class ObjectMonitor {
private: private:
void AddWaiter(ObjectWaiter * waiter); void AddWaiter(ObjectWaiter * waiter);
static void DeferredInitialize();
void INotify(Thread * Self); void INotify(Thread * Self);
ObjectWaiter * DequeueWaiter(); ObjectWaiter * DequeueWaiter();
void DequeueSpecificWaiter(ObjectWaiter * waiter); void DequeueSpecificWaiter(ObjectWaiter * waiter);