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8299614: Shenandoah: STW mark should keep nmethod/oops referenced from stack chunk alive

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Reviewed-by: rkennke, zgu
This commit is contained in:
Aleksey Shipilev 2023-09-13 06:04:10 +00:00
parent a36f5a54ab
commit ece9bdfc83
15 changed files with 46 additions and 32 deletions
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1
src/hotspot/share/gc/shenandoah/mode/shenandoahIUMode.cpp
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@ -60,7 +60,6 @@ void ShenandoahIUMode::initialize_flags() const {
SHENANDOAH_CHECK_FLAG_SET(ShenandoahIUBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahNMethodBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahStackWatermarkBarrier);
}

1
src/hotspot/share/gc/shenandoah/mode/shenandoahPassiveMode.cpp
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@ -50,7 +50,6 @@ void ShenandoahPassiveMode::initialize_flags() const {
SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahIUBarrier);
SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahCASBarrier);
SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahCloneBarrier);
SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahNMethodBarrier);
SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahStackWatermarkBarrier);
// Final configuration checks

1
src/hotspot/share/gc/shenandoah/mode/shenandoahSATBMode.cpp
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@ -48,7 +48,6 @@ void ShenandoahSATBMode::initialize_flags() const {
SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahNMethodBarrier);
SHENANDOAH_CHECK_FLAG_SET(ShenandoahStackWatermarkBarrier);
}

2
src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.cpp
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@ -45,7 +45,7 @@ ShenandoahBarrierSet::ShenandoahBarrierSet(ShenandoahHeap* heap) :
BarrierSet(make_barrier_set_assembler<ShenandoahBarrierSetAssembler>(),
make_barrier_set_c1<ShenandoahBarrierSetC1>(),
make_barrier_set_c2<ShenandoahBarrierSetC2>(),
ShenandoahNMethodBarrier ? new ShenandoahBarrierSetNMethod(heap) : nullptr,
new ShenandoahBarrierSetNMethod(heap),
new ShenandoahBarrierSetStackChunk(),
BarrierSet::FakeRtti(BarrierSet::ShenandoahBarrierSet)),
_heap(heap),

25
src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.cpp
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@ -104,6 +104,20 @@ void ShenandoahParallelCodeHeapIterator::parallel_blobs_do(CodeBlobClosure* f) {
ShenandoahNMethodTable* ShenandoahCodeRoots::_nmethod_table;
int ShenandoahCodeRoots::_disarmed_value = 1;
bool ShenandoahCodeRoots::use_nmethod_barriers_for_mark() {
// Continuations need nmethod barriers for scanning stack chunk nmethods.
if (Continuations::enabled()) return true;
// Concurrent class unloading needs nmethod barriers.
// When a nmethod is about to be executed, we need to make sure that all its
// metadata are marked. The alternative is to remark thread roots at final mark
// pause, which would cause latency issues.
if (ShenandoahHeap::heap()->unload_classes()) return true;
// Otherwise, we can go without nmethod barriers.
return false;
}
void ShenandoahCodeRoots::initialize() {
_nmethod_table = new ShenandoahNMethodTable();
}
@ -118,8 +132,13 @@ void ShenandoahCodeRoots::unregister_nmethod(nmethod* nm) {
_nmethod_table->unregister_nmethod(nm);
}
void ShenandoahCodeRoots::arm_nmethods() {
assert(BarrierSet::barrier_set()->barrier_set_nmethod() != nullptr, "Sanity");
void ShenandoahCodeRoots::arm_nmethods_for_mark() {
if (use_nmethod_barriers_for_mark()) {
BarrierSet::barrier_set()->barrier_set_nmethod()->arm_all_nmethods();
}
}
void ShenandoahCodeRoots::arm_nmethods_for_evac() {
BarrierSet::barrier_set()->barrier_set_nmethod()->arm_all_nmethods();
}
@ -163,7 +182,7 @@ public:
};
void ShenandoahCodeRoots::disarm_nmethods() {
if (ShenandoahNMethodBarrier) {
if (use_nmethod_barriers_for_mark()) {
ShenandoahDisarmNMethodsTask task;
ShenandoahHeap::heap()->workers()->run_task(&task);
}

5
src/hotspot/share/gc/shenandoah/shenandoahCodeRoots.hpp
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@ -97,11 +97,14 @@ public:
// Concurrent nmethod unloading support
static void unlink(WorkerThreads* workers, bool unloading_occurred);
static void purge();
static void arm_nmethods();
static void arm_nmethods_for_mark();
static void arm_nmethods_for_evac();
static void disarm_nmethods();
static int disarmed_value() { return _disarmed_value; }
static int* disarmed_value_address() { return &_disarmed_value; }
static bool use_nmethod_barriers_for_mark();
private:
static ShenandoahNMethodTable* _nmethod_table;
static int _disarmed_value;

11
src/hotspot/share/gc/shenandoah/shenandoahConcurrentGC.cpp
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@ -545,12 +545,9 @@ void ShenandoahConcurrentGC::op_init_mark() {
// Make above changes visible to worker threads
OrderAccess::fence();
// Arm nmethods for concurrent marking. When a nmethod is about to be executed,
// we need to make sure that all its metadata are marked. alternative is to remark
// thread roots at final mark pause, but it can be potential latency killer.
if (heap->unload_classes()) {
ShenandoahCodeRoots::arm_nmethods();
}
// Arm nmethods for concurrent mark
ShenandoahCodeRoots::arm_nmethods_for_mark();
ShenandoahStackWatermark::change_epoch_id();
if (ShenandoahPacing) {
@ -603,7 +600,7 @@ void ShenandoahConcurrentGC::op_final_mark() {
}
// Arm nmethods/stack for concurrent processing
ShenandoahCodeRoots::arm_nmethods();
ShenandoahCodeRoots::arm_nmethods_for_evac();
ShenandoahStackWatermark::change_epoch_id();
if (ShenandoahPacing) {

8
src/hotspot/share/gc/shenandoah/shenandoahDegeneratedGC.cpp
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@ -181,11 +181,9 @@ void ShenandoahDegenGC::op_degenerated() {
assert(!heap->cancelled_gc(), "STW reference update can not OOM");
}
if (ClassUnloading) {
// Disarm nmethods that armed in concurrent cycle.
// In above case, update roots should disarm them
ShenandoahCodeRoots::disarm_nmethods();
}
// Disarm nmethods that armed in concurrent cycle.
// In above case, update roots should disarm them
ShenandoahCodeRoots::disarm_nmethods();
op_cleanup_complete();
break;

4
src/hotspot/share/gc/shenandoah/shenandoahNMethod.inline.hpp
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@ -80,9 +80,7 @@ void ShenandoahNMethod::heal_nmethod_metadata(ShenandoahNMethod* nmethod_data) {
void ShenandoahNMethod::disarm_nmethod(nmethod* nm) {
BarrierSetNMethod* const bs = BarrierSet::barrier_set()->barrier_set_nmethod();
assert(bs != nullptr || !ShenandoahNMethodBarrier,
"Must have nmethod barrier for concurrent GC");
if (bs != nullptr && bs->is_armed(nm)) {
if (bs->is_armed(nm)) {
bs->disarm(nm);
}
}

2
src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.cpp
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@ -206,7 +206,7 @@ ShenandoahRootAdjuster::ShenandoahRootAdjuster(uint n_workers, ShenandoahPhaseTi
void ShenandoahRootAdjuster::roots_do(uint worker_id, OopClosure* oops) {
CodeBlobToOopClosure code_blob_cl(oops, CodeBlobToOopClosure::FixRelocations);
ShenandoahCodeBlobAndDisarmClosure blobs_and_disarm_Cl(oops);
CodeBlobToOopClosure* adjust_code_closure = (ClassUnloading && ShenandoahNMethodBarrier) ?
CodeBlobToOopClosure* adjust_code_closure = ShenandoahCodeRoots::use_nmethod_barriers_for_mark() ?
static_cast<CodeBlobToOopClosure*>(&blobs_and_disarm_Cl) :
static_cast<CodeBlobToOopClosure*>(&code_blob_cl);
CLDToOopClosure adjust_cld_closure(oops, ClassLoaderData::_claim_strong);

2
src/hotspot/share/gc/shenandoah/shenandoahRootProcessor.inline.hpp
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@ -172,7 +172,7 @@ template <typename IsAlive, typename KeepAlive>
void ShenandoahRootUpdater::roots_do(uint worker_id, IsAlive* is_alive, KeepAlive* keep_alive) {
CodeBlobToOopClosure update_blobs(keep_alive, CodeBlobToOopClosure::FixRelocations);
ShenandoahCodeBlobAndDisarmClosure blobs_and_disarm_Cl(keep_alive);
CodeBlobToOopClosure* codes_cl = (ClassUnloading && ShenandoahNMethodBarrier) ?
CodeBlobToOopClosure* codes_cl = ShenandoahCodeRoots::use_nmethod_barriers_for_mark() ?
static_cast<CodeBlobToOopClosure*>(&blobs_and_disarm_Cl) :
static_cast<CodeBlobToOopClosure*>(&update_blobs);

10
src/hotspot/share/gc/shenandoah/shenandoahSTWMark.cpp
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@ -89,8 +89,13 @@ ShenandoahSTWMark::ShenandoahSTWMark(bool full_gc) :
}
void ShenandoahSTWMark::mark() {
// Weak reference processing
ShenandoahHeap* const heap = ShenandoahHeap::heap();
// Arm all nmethods. Even though this is STW mark, some marking code
// piggybacks on nmethod barriers for special instances.
ShenandoahCodeRoots::arm_nmethods_for_mark();
// Weak reference processing
ShenandoahReferenceProcessor* rp = heap->ref_processor();
rp->reset_thread_locals();
rp->set_soft_reference_policy(heap->soft_ref_policy()->should_clear_all_soft_refs());
@ -120,6 +125,9 @@ void ShenandoahSTWMark::mark() {
heap->mark_complete_marking_context();
end_mark();
// Mark is finished, can disarm the nmethods now.
ShenandoahCodeRoots::disarm_nmethods();
assert(task_queues()->is_empty(), "Should be empty");
TASKQUEUE_STATS_ONLY(task_queues()->print_taskqueue_stats());
TASKQUEUE_STATS_ONLY(task_queues()->reset_taskqueue_stats());

3
src/hotspot/share/gc/shenandoah/shenandoah_globals.hpp
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@ -352,9 +352,6 @@
product(bool, ShenandoahLoadRefBarrier, true, DIAGNOSTIC, \
"Turn on/off load-reference barriers in Shenandoah") \
\
product(bool, ShenandoahNMethodBarrier, true, DIAGNOSTIC, \
"Turn on/off NMethod entry barriers in Shenandoah") \
\
product(bool, ShenandoahStackWatermarkBarrier, true, DIAGNOSTIC, \
"Turn on/off stack watermark barriers in Shenandoah") \
\

1
test/hotspot/jtreg/gc/shenandoah/options/TestSelectiveBarrierFlags.java
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@ -54,7 +54,6 @@ public class TestSelectiveBarrierFlags {
new String[] { "ShenandoahSATBBarrier", "ShenandoahIUBarrier" },
new String[] { "ShenandoahCASBarrier" },
new String[] { "ShenandoahCloneBarrier" },
new String[] { "ShenandoahNMethodBarrier" },
new String[] { "ShenandoahStackWatermarkBarrier" }
};

2
test/hotspot/jtreg/gc/shenandoah/options/TestWrongBarrierDisable.java
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@ -42,7 +42,6 @@ public class TestWrongBarrierDisable {
"ShenandoahSATBBarrier",
"ShenandoahCASBarrier",
"ShenandoahCloneBarrier",
"ShenandoahNMethodBarrier",
"ShenandoahStackWatermarkBarrier",
};
String[] iu = {
@ -50,7 +49,6 @@ public class TestWrongBarrierDisable {
"ShenandoahIUBarrier",
"ShenandoahCASBarrier",
"ShenandoahCloneBarrier",
"ShenandoahNMethodBarrier",
"ShenandoahStackWatermarkBarrier",
};