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7147724: G1: hang in SurrogateLockerThread::manipulatePLL

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Attempting to initiate a marking cycle when allocating a humongous object can, if a marking cycle is successfully initiated by another thread, result in the allocating thread spinning until the marking cycle is complete. Eliminate a deadlock between the main ConcurrentMarkThread, the SurrogateLocker thread, the VM thread, and a mutator thread waiting on the SecondaryFreeList_lock (while free regions are going to become available) by not manipulating the pending list lock during the prologue and epilogue of the cleanup pause.

Reviewed-by: brutisso, jcoomes, tonyp
This commit is contained in:
John Cuthbertson 2012-03-12 14:59:00 -07:00
parent 8950ee8d8e
commit 006def0451
4 changed files with 74 additions and 22 deletions
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4
hotspot/src/share/vm/gc_implementation/g1/concurrentMarkThread.cpp
View File

@ -155,7 +155,7 @@ void ConcurrentMarkThread::run() {
CMCheckpointRootsFinalClosure final_cl(_cm);
sprintf(verbose_str, "GC remark");
VM_CGC_Operation op(&final_cl, verbose_str);
VM_CGC_Operation op(&final_cl, verbose_str, true /* needs_pll */);
VMThread::execute(&op);
}
if (cm()->restart_for_overflow() &&
@ -189,7 +189,7 @@ void ConcurrentMarkThread::run() {
CMCleanUp cl_cl(_cm);
sprintf(verbose_str, "GC cleanup");
VM_CGC_Operation op(&cl_cl, verbose_str);
VM_CGC_Operation op(&cl_cl, verbose_str, false /* needs_pll */);
VMThread::execute(&op);
} else {
// We don't want to update the marking status if a GC pause

16
hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp
View File

@ -993,7 +993,7 @@ HeapWord* G1CollectedHeap::attempt_allocation_slow(size_t word_size,
// iteration (after taking the Heap_lock).
result = _mutator_alloc_region.attempt_allocation(word_size,
false /* bot_updates */);
if (result != NULL ){
if (result != NULL) {
return result;
}
@ -2437,20 +2437,22 @@ void G1CollectedHeap::collect(GCCause::Cause cause) {
true, /* should_initiate_conc_mark */
g1_policy()->max_pause_time_ms(),
cause);
VMThread::execute(&op);
if (!op.pause_succeeded()) {
// Another GC got scheduled and prevented us from scheduling
// the initial-mark GC. It's unlikely that the GC that
// pre-empted us was also an initial-mark GC. So, we'll retry
// the initial-mark GC.
if (full_gc_count_before == total_full_collections()) {
retry_gc = true;
retry_gc = op.should_retry_gc();
} else {
// A Full GC happened while we were trying to schedule the
// initial-mark GC. No point in starting a new cycle given
// that the whole heap was collected anyway.
}
if (retry_gc) {
if (GC_locker::is_active_and_needs_gc()) {
GC_locker::stall_until_clear();
}
}
}
} else {
if (cause == GCCause::_gc_locker

61
hotspot/src/share/vm/gc_implementation/g1/vm_operations_g1.cpp
View File

@ -34,7 +34,8 @@
VM_G1CollectForAllocation::VM_G1CollectForAllocation(
unsigned int gc_count_before,
size_t word_size)
: VM_G1OperationWithAllocRequest(gc_count_before, word_size) {
: VM_G1OperationWithAllocRequest(gc_count_before, word_size,
GCCause::_allocation_failure) {
guarantee(word_size > 0, "an allocation should always be requested");
}
@ -57,9 +58,10 @@ VM_G1IncCollectionPause::VM_G1IncCollectionPause(
bool should_initiate_conc_mark,
double target_pause_time_ms,
GCCause::Cause gc_cause)
: VM_G1OperationWithAllocRequest(gc_count_before, word_size),
: VM_G1OperationWithAllocRequest(gc_count_before, word_size, gc_cause),
_should_initiate_conc_mark(should_initiate_conc_mark),
_target_pause_time_ms(target_pause_time_ms),
_should_retry_gc(false),
_full_collections_completed_before(0) {
guarantee(target_pause_time_ms > 0.0,
err_msg("target_pause_time_ms = %1.6lf should be positive",
@ -70,6 +72,22 @@ VM_G1IncCollectionPause::VM_G1IncCollectionPause(
_gc_cause = gc_cause;
}
bool VM_G1IncCollectionPause::doit_prologue() {
bool res = VM_GC_Operation::doit_prologue();
if (!res) {
if (_should_initiate_conc_mark) {
// The prologue can fail for a couple of reasons. The first is that another GC
// got scheduled and prevented the scheduling of the initial mark GC. The
// second is that the GC locker may be active and the heap can't be expanded.
// In both cases we want to retry the GC so that the initial mark pause is
// actually scheduled. In the second case, however, we should stall until
// until the GC locker is no longer active and then retry the initial mark GC.
_should_retry_gc = true;
}
}
return res;
}
void VM_G1IncCollectionPause::doit() {
G1CollectedHeap* g1h = G1CollectedHeap::heap();
assert(!_should_initiate_conc_mark ||
@ -106,11 +124,25 @@ void VM_G1IncCollectionPause::doit() {
// next GC pause to be an initial mark; it returns false if a
// marking cycle is already in progress.
//
// If a marking cycle is already in progress just return and skip
// the pause - the requesting thread should block in doit_epilogue
// until the marking cycle is complete.
// If a marking cycle is already in progress just return and skip the
// pause below - if the reason for requesting this initial mark pause
// was due to a System.gc() then the requesting thread should block in
// doit_epilogue() until the marking cycle is complete.
//
// If this initial mark pause was requested as part of a humongous
// allocation then we know that the marking cycle must just have
// been started by another thread (possibly also allocating a humongous
// object) as there was no active marking cycle when the requesting
// thread checked before calling collect() in
// attempt_allocation_humongous(). Retrying the GC, in this case,
// will cause the requesting thread to spin inside collect() until the
// just started marking cycle is complete - which may be a while. So
// we do NOT retry the GC.
if (!res) {
assert(_word_size == 0, "ExplicitGCInvokesConcurrent shouldn't be allocating");
assert(_word_size == 0, "Concurrent Full GC/Humongous Object IM shouldn't be allocating");
if (_gc_cause != GCCause::_g1_humongous_allocation) {
_should_retry_gc = true;
}
return;
}
}
@ -123,6 +155,13 @@ void VM_G1IncCollectionPause::doit() {
true /* expect_null_cur_alloc_region */);
} else {
assert(_result == NULL, "invariant");
if (!_pause_succeeded) {
// Another possible reason reason for the pause to not be successful
// is that, again, the GC locker is active (and has become active
// since the prologue was executed). In this case we should retry
// the pause after waiting for the GC locker to become inactive.
_should_retry_gc = true;
}
}
}
@ -168,6 +207,7 @@ void VM_G1IncCollectionPause::doit_epilogue() {
}
void VM_CGC_Operation::acquire_pending_list_lock() {
assert(_needs_pll, "don't call this otherwise");
// The caller may block while communicating
// with the SLT thread in order to acquire/release the PLL.
ConcurrentMarkThread::slt()->
@ -175,6 +215,7 @@ void VM_CGC_Operation::acquire_pending_list_lock() {
}
void VM_CGC_Operation::release_and_notify_pending_list_lock() {
assert(_needs_pll, "don't call this otherwise");
// The caller may block while communicating
// with the SLT thread in order to acquire/release the PLL.
ConcurrentMarkThread::slt()->
@ -198,7 +239,9 @@ void VM_CGC_Operation::doit() {
bool VM_CGC_Operation::doit_prologue() {
// Note the relative order of the locks must match that in
// VM_GC_Operation::doit_prologue() or deadlocks can occur
acquire_pending_list_lock();
if (_needs_pll) {
acquire_pending_list_lock();
}
Heap_lock->lock();
SharedHeap::heap()->_thread_holds_heap_lock_for_gc = true;
@ -210,5 +253,7 @@ void VM_CGC_Operation::doit_epilogue() {
// VM_GC_Operation::doit_epilogue()
SharedHeap::heap()->_thread_holds_heap_lock_for_gc = false;
Heap_lock->unlock();
release_and_notify_pending_list_lock();
if (_needs_pll) {
release_and_notify_pending_list_lock();
}
}

15
hotspot/src/share/vm/gc_implementation/g1/vm_operations_g1.hpp
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -43,8 +43,9 @@ protected:
public:
VM_G1OperationWithAllocRequest(unsigned int gc_count_before,
size_t word_size)
: VM_GC_Operation(gc_count_before, GCCause::_allocation_failure),
size_t word_size,
GCCause::Cause gc_cause)
: VM_GC_Operation(gc_count_before, gc_cause),
_word_size(word_size), _result(NULL), _pause_succeeded(false) { }
HeapWord* result() { return _result; }
bool pause_succeeded() { return _pause_succeeded; }
@ -77,6 +78,7 @@ public:
class VM_G1IncCollectionPause: public VM_G1OperationWithAllocRequest {
private:
bool _should_initiate_conc_mark;
bool _should_retry_gc;
double _target_pause_time_ms;
unsigned int _full_collections_completed_before;
public:
@ -86,11 +88,13 @@ public:
double target_pause_time_ms,
GCCause::Cause gc_cause);
virtual VMOp_Type type() const { return VMOp_G1IncCollectionPause; }
virtual bool doit_prologue();
virtual void doit();
virtual void doit_epilogue();
virtual const char* name() const {
return "garbage-first incremental collection pause";
}
bool should_retry_gc() const { return _should_retry_gc; }
};
// Concurrent GC stop-the-world operations such as remark and cleanup;
@ -98,6 +102,7 @@ public:
class VM_CGC_Operation: public VM_Operation {
VoidClosure* _cl;
const char* _printGCMessage;
bool _needs_pll;
protected:
// java.lang.ref.Reference support
@ -105,8 +110,8 @@ protected:
void release_and_notify_pending_list_lock();
public:
VM_CGC_Operation(VoidClosure* cl, const char *printGCMsg)
: _cl(cl), _printGCMessage(printGCMsg) { }
VM_CGC_Operation(VoidClosure* cl, const char *printGCMsg, bool needs_pll)
: _cl(cl), _printGCMessage(printGCMsg), _needs_pll(needs_pll) { }
virtual VMOp_Type type() const { return VMOp_CGC_Operation; }
virtual void doit();
virtual bool doit_prologue();