/** Process the phase stack. This method is called by multiple threads. */
private static boolean processPhaseStack(boolean resume) {
int order = VM.collection.rendezvous(1001);
final boolean primary = order == 1;
boolean log = Options.verbose.getValue() >= 6;
boolean logDetails = Options.verbose.getValue() >= 7;
if (primary && resume) {
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!Phase.isPhaseStackEmpty());
if (VM.VERIFY_ASSERTIONS) VM.assertions._assert(!Plan.gcInProgress());
Plan.setGCStatus(Plan.GC_PROPER);
}
/* In order to reduce the need for synchronization, we keep an odd or even
* counter for the number of phases processed. As each phase has a single
* rendezvous it is only possible to be out by one so the odd or even counter
* protects us. */
boolean isEvenPhase = true;
if (primary) {
/* First phase will be even, so we say we are odd here so that the next phase set is even*/
setNextPhase(false, getNextPhase(), false);
}
/* Make sure everyone sees the first phase */
VM.collection.rendezvous(1002);
/* Global and Collector instances used in phases */
Plan plan = VM.activePlan.global();
CollectorContext collector = VM.activePlan.collector();
/* The main phase execution loop */
int scheduledPhase;
while ((scheduledPhase = getCurrentPhase(isEvenPhase)) > 0) {
short schedule = getSchedule(scheduledPhase);
short phaseId = getPhaseId(scheduledPhase);
Phase p = getPhase(phaseId);
/* Start the timer(s) */
if (primary) {
if (resume) {
resumeComplexTimers();
}
if (p.timer != null) p.timer.start();
if (startComplexTimer > 0) {
Phase.getPhase(startComplexTimer).timer.start();
startComplexTimer = 0;
}
}
if (log) {
Log.write("Execute ");
p.logPhase();
}
/* Execute a single simple scheduled phase */
switch (schedule) {
/* Global phase */
case SCHEDULE_GLOBAL:
{
if (logDetails) Log.writeln(" as Global...");
if (primary) plan.collectionPhase(phaseId);
break;
}
/* Collector phase */
case SCHEDULE_COLLECTOR:
{
if (logDetails) Log.writeln(" as Collector...");
collector.collectionPhase(phaseId, primary);
break;
}
/* Mutator phase */
case SCHEDULE_MUTATOR:
{
if (logDetails) Log.writeln(" as Mutator...");
/* Iterate through all mutator contexts */
MutatorContext mutator;
while ((mutator = VM.activePlan.getNextMutator()) != null) {
mutator.collectionPhase(phaseId, primary);
}
break;
}
/* Concurrent phase */
case SCHEDULE_CONCURRENT:
{
/* We are yielding to a concurrent collection phase */
if (logDetails) Log.writeln(" as Concurrent, yielding...");
if (primary) {
concurrentPhaseId = phaseId;
scheduleConcurrentWorkers();
/* Concurrent phase, we need to stop gc */
Plan.setGCStatus(Plan.NOT_IN_GC);
}
VM.collection.rendezvous(1003);
if (primary) {
pauseComplexTimers();
}
return false;
}
default:
{
/* getNextPhase has done the wrong thing */
VM.assertions.fail("Invalid schedule in Phase.processPhaseStack");
break;
}
}
if (primary) {
/* Set the next phase by processing the stack */
int next = getNextPhase();
boolean needsResetRendezvous =
(next > 0) && (schedule == SCHEDULE_MUTATOR && getSchedule(next) == SCHEDULE_MUTATOR);
setNextPhase(isEvenPhase, next, needsResetRendezvous);
}
/* Sync point after execution of a phase */
VM.collection.rendezvous(1004);
/* Mutator phase reset */
if (primary && schedule == SCHEDULE_MUTATOR) {
VM.activePlan.resetMutatorIterator();
}
/* At this point, in the case of consecutive phases with mutator
* scheduling, we have to double-synchronize to ensure all
* collector threads see the reset mutator counter. */
if (needsMutatorResetRendezvous(isEvenPhase)) {
VM.collection.rendezvous(1005);
}
/* Stop the timer(s) */
if (primary) {
if (p.timer != null) p.timer.stop();
if (stopComplexTimer > 0) {
Phase.getPhase(stopComplexTimer).timer.stop();
stopComplexTimer = 0;
}
}
/* Flip the even / odd phase sense */
isEvenPhase = !isEvenPhase;
resume = false;
}
/* Phase stack exhausted so we return true */
return true;
}