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openjdk-11/8215047-Task-terminators-do-not-complete-termination-in-consistent-state.patch

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diff --git a/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp b/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp
index 3749a99bb..ef8fb4ac0 100644
--- a/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp
+++ b/src/hotspot/share/gc/g1/g1ConcurrentMark.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2019, 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
@@ -2202,7 +2202,10 @@ void G1CMTask::reset(G1CMBitMap* next_mark_bitmap) {
}
bool G1CMTask::should_exit_termination() {
- regular_clock_call();
+ if (!regular_clock_call()) {
+ return true;
+ }
+
// This is called when we are in the termination protocol. We should
// quit if, for some reason, this task wants to abort or the global
// stack is not empty (this means that we can get work from it).
@@ -2213,12 +2216,12 @@ void G1CMTask::reached_limit() {
assert(_words_scanned >= _words_scanned_limit ||
_refs_reached >= _refs_reached_limit ,
"shouldn't have been called otherwise");
- regular_clock_call();
+ abort_marking_if_regular_check_fail();
}
-void G1CMTask::regular_clock_call() {
+bool G1CMTask::regular_clock_call() {
if (has_aborted()) {
- return;
+ return false;
}
// First, we need to recalculate the words scanned and refs reached
@@ -2229,21 +2232,19 @@ void G1CMTask::regular_clock_call() {
// (1) If an overflow has been flagged, then we abort.
if (_cm->has_overflown()) {
- set_has_aborted();
- return;
+ return false;
}
// If we are not concurrent (i.e. we're doing remark) we don't need
// to check anything else. The other steps are only needed during
// the concurrent marking phase.
if (!_cm->concurrent()) {
- return;
+ return true;
}
// (2) If marking has been aborted for Full GC, then we also abort.
if (_cm->has_aborted()) {
- set_has_aborted();
- return;
+ return false;
}
double curr_time_ms = os::elapsedVTime() * 1000.0;
@@ -2252,17 +2253,15 @@ void G1CMTask::regular_clock_call() {
if (SuspendibleThreadSet::should_yield()) {
// We should yield. To do this we abort the task. The caller is
// responsible for yielding.
- set_has_aborted();
- return;
+ return false;
}
// (5) We check whether we've reached our time quota. If we have,
// then we abort.
double elapsed_time_ms = curr_time_ms - _start_time_ms;
if (elapsed_time_ms > _time_target_ms) {
- set_has_aborted();
_has_timed_out = true;
- return;
+ return false;
}
// (6) Finally, we check whether there are enough completed STAB
@@ -2271,9 +2270,9 @@ void G1CMTask::regular_clock_call() {
if (!_draining_satb_buffers && satb_mq_set.process_completed_buffers()) {
// we do need to process SATB buffers, we'll abort and restart
// the marking task to do so
- set_has_aborted();
- return;
+ return false;
}
+ return true;
}
void G1CMTask::recalculate_limits() {
@@ -2428,7 +2427,7 @@ void G1CMTask::drain_satb_buffers() {
// until we run out of buffers or we need to abort.
while (!has_aborted() &&
satb_mq_set.apply_closure_to_completed_buffer(&satb_cl)) {
- regular_clock_call();
+ abort_marking_if_regular_check_fail();
}
_draining_satb_buffers = false;
@@ -2671,7 +2670,7 @@ void G1CMTask::do_marking_step(double time_target_ms,
// If the iteration is successful, give up the region.
if (mr.is_empty()) {
giveup_current_region();
- regular_clock_call();
+ abort_marking_if_regular_check_fail();
} else if (_curr_region->is_humongous() && mr.start() == _curr_region->bottom()) {
if (_next_mark_bitmap->is_marked(mr.start())) {
// The object is marked - apply the closure
@@ -2680,10 +2679,10 @@ void G1CMTask::do_marking_step(double time_target_ms,
// Even if this task aborted while scanning the humongous object
// we can (and should) give up the current region.
giveup_current_region();
- regular_clock_call();
+ abort_marking_if_regular_check_fail();
} else if (_next_mark_bitmap->iterate(&bitmap_closure, mr)) {
giveup_current_region();
- regular_clock_call();
+ abort_marking_if_regular_check_fail();
} else {
assert(has_aborted(), "currently the only way to do so");
// The only way to abort the bitmap iteration is to return
@@ -2738,7 +2737,7 @@ void G1CMTask::do_marking_step(double time_target_ms,
// block of empty regions. So we need to call the regular clock
// method once round the loop to make sure it's called
// frequently enough.
- regular_clock_call();
+ abort_marking_if_regular_check_fail();
}
if (!has_aborted() && _curr_region == NULL) {
@@ -2816,6 +2815,7 @@ void G1CMTask::do_marking_step(double time_target_ms,
guarantee(_cm->mark_stack_empty(), "only way to reach here");
guarantee(_task_queue->size() == 0, "only way to reach here");
guarantee(!_cm->has_overflown(), "only way to reach here");
+ guarantee(!has_aborted(), "should never happen if termination has completed");
} else {
// Apparently there's more work to do. Let's abort this task. It
// will restart it and we can hopefully find more things to do.
diff --git a/src/hotspot/share/gc/g1/g1ConcurrentMark.hpp b/src/hotspot/share/gc/g1/g1ConcurrentMark.hpp
index b5eb26197..b760fe977 100644
--- a/src/hotspot/share/gc/g1/g1ConcurrentMark.hpp
+++ b/src/hotspot/share/gc/g1/g1ConcurrentMark.hpp
@@ -730,7 +730,11 @@ private:
// Supposed to be called regularly during a marking step as
// it checks a bunch of conditions that might cause the marking step
// to abort
- void regular_clock_call();
+ // Return true if the marking step should continue. Otherwise, return false to abort
+ bool regular_clock_call();
+
+ // Set abort flag if regular_clock_call() check fails
+ inline void abort_marking_if_regular_check_fail();
// Test whether obj might have already been passed over by the
// mark bitmap scan, and so needs to be pushed onto the mark stack.
diff --git a/src/hotspot/share/gc/g1/g1ConcurrentMark.inline.hpp b/src/hotspot/share/gc/g1/g1ConcurrentMark.inline.hpp
index 4a969c511..383cdc563 100644
--- a/src/hotspot/share/gc/g1/g1ConcurrentMark.inline.hpp
+++ b/src/hotspot/share/gc/g1/g1ConcurrentMark.inline.hpp
@@ -210,6 +210,12 @@ inline void G1ConcurrentMark::add_to_liveness(uint worker_id, oop const obj, siz
task(worker_id)->update_liveness(obj, size);
}
+inline void G1CMTask::abort_marking_if_regular_check_fail() {
+ if (!regular_clock_call()) {
+ set_has_aborted();
+ }
+}
+
inline bool G1CMTask::make_reference_grey(oop obj) {
if (!_cm->mark_in_next_bitmap(_worker_id, obj)) {
return false;
diff --git a/src/hotspot/share/gc/shared/owstTaskTerminator.cpp b/src/hotspot/share/gc/shared/owstTaskTerminator.cpp
index 3c32ab627..2856a9981 100644
--- a/src/hotspot/share/gc/shared/owstTaskTerminator.cpp
+++ b/src/hotspot/share/gc/shared/owstTaskTerminator.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
+ * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
@@ -38,15 +38,17 @@ bool OWSTTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
// Single worker, done
if (_n_threads == 1) {
_offered_termination = 1;
+ assert(!peek_in_queue_set(), "Precondition");
return true;
}
_blocker->lock_without_safepoint_check();
- // All arrived, done
_offered_termination++;
+ // All arrived, done
if (_offered_termination == _n_threads) {
_blocker->notify_all();
_blocker->unlock();
+ assert(!peek_in_queue_set(), "Precondition");
return true;
}
@@ -59,21 +61,31 @@ bool OWSTTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
if (do_spin_master_work(terminator)) {
assert(_offered_termination == _n_threads, "termination condition");
+ assert(!peek_in_queue_set(), "Precondition");
return true;
} else {
_blocker->lock_without_safepoint_check();
+ // There is possibility that termination is reached between dropping the lock
+ // before returning from do_spin_master_work() and acquiring lock above.
+ if (_offered_termination == _n_threads) {
+ _blocker->unlock();
+ assert(!peek_in_queue_set(), "Precondition");
+ return true;
+ }
}
} else {
_blocker->wait(true, WorkStealingSleepMillis);
if (_offered_termination == _n_threads) {
_blocker->unlock();
+ assert(!peek_in_queue_set(), "Precondition");
return true;
}
}
size_t tasks = tasks_in_queue_set();
if (exit_termination(tasks, terminator)) {
+ assert_lock_strong(_blocker);
_offered_termination--;
_blocker->unlock();
return false;
@@ -153,19 +165,24 @@ bool OWSTTaskTerminator::do_spin_master_work(TerminatorTerminator* terminator) {
_total_peeks++;
#endif
size_t tasks = tasks_in_queue_set();
- if (exit_termination(tasks, terminator)) {
+ bool exit = exit_termination(tasks, terminator);
+ {
MonitorLockerEx locker(_blocker, Mutex::_no_safepoint_check_flag);
- if (tasks >= _offered_termination - 1) {
- locker.notify_all();
- } else {
- for (; tasks > 1; tasks--) {
- locker.notify();
+ // Termination condition reached
+ if (_offered_termination == _n_threads) {
+ _spin_master = NULL;
+ return true;
+ } else if (exit) {
+ if (tasks >= _offered_termination - 1) {
+ locker.notify_all();
+ } else {
+ for (; tasks > 1; tasks--) {
+ locker.notify();
+ }
}
+ _spin_master = NULL;
+ return false;
}
- _spin_master = NULL;
- return false;
- } else if (_offered_termination == _n_threads) {
- return true;
}
}
}
diff --git a/src/hotspot/share/gc/shared/owstTaskTerminator.hpp b/src/hotspot/share/gc/shared/owstTaskTerminator.hpp
index 9e6fe135a..190033eb7 100644
--- a/src/hotspot/share/gc/shared/owstTaskTerminator.hpp
+++ b/src/hotspot/share/gc/shared/owstTaskTerminator.hpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
+ * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
@@ -55,6 +55,7 @@ public:
}
virtual ~OWSTTaskTerminator() {
+ assert(_spin_master == NULL, "Should have been reset");
assert(_blocker != NULL, "Can not be NULL");
delete _blocker;
}
diff --git a/src/hotspot/share/gc/shared/taskqueue.cpp b/src/hotspot/share/gc/shared/taskqueue.cpp
index 47639bdf9..697c13645 100644
--- a/src/hotspot/share/gc/shared/taskqueue.cpp
+++ b/src/hotspot/share/gc/shared/taskqueue.cpp
@@ -1,5 +1,5 @@
/*
- * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2019, 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
@@ -25,6 +25,9 @@
#include "precompiled.hpp"
#include "gc/shared/taskqueue.hpp"
#include "gc/shared/owstTaskTerminator.hpp"
+#if INCLUDE_SHENANDOAHGC
+#include "gc/shenandoah/shenandoahHeap.hpp"
+#endif
#include "oops/oop.inline.hpp"
#include "logging/log.hpp"
#include "runtime/atomic.hpp"
@@ -118,6 +121,14 @@ ParallelTaskTerminator(uint n_threads, TaskQueueSetSuper* queue_set) :
_queue_set(queue_set),
_offered_termination(0) {}
+ParallelTaskTerminator::~ParallelTaskTerminator() {
+ assert(_offered_termination == 0 || !peek_in_queue_set(), "Precondition");
+#if INCLUDE_SHENANDOAHGC
+ if (UseShenandoahGC && ShenandoahHeap::heap()->cancelled_gc()) return;
+#endif
+ assert(_offered_termination == 0 || _offered_termination == _n_threads, "Terminated or aborted" );
+}
+
bool ParallelTaskTerminator::peek_in_queue_set() {
return _queue_set->peek();
}
@@ -162,6 +173,7 @@ ParallelTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
assert(_offered_termination <= _n_threads, "Invariant");
// Are all threads offering termination?
if (_offered_termination == _n_threads) {
+ assert(!peek_in_queue_set(), "Precondition");
return true;
} else {
// Look for more work.
@@ -211,9 +223,7 @@ ParallelTaskTerminator::offer_termination(TerminatorTerminator* terminator) {
#endif
if (peek_in_queue_set() ||
(terminator != NULL && terminator->should_exit_termination())) {
- Atomic::dec(&_offered_termination);
- assert(_offered_termination < _n_threads, "Invariant");
- return false;
+ return complete_or_exit_termination();
}
}
}
@@ -229,6 +239,23 @@ void ParallelTaskTerminator::print_termination_counts() {
}
#endif
+bool ParallelTaskTerminator::complete_or_exit_termination() {
+ // If termination is ever reached, terminator should stay in such state,
+ // so that all threads see the same state
+ uint current_offered = _offered_termination;
+ uint expected_value;
+ do {
+ if (current_offered == _n_threads) {
+ assert(!peek_in_queue_set(), "Precondition");
+ return true;
+ }
+ expected_value = current_offered;
+ } while ((current_offered = Atomic::cmpxchg(current_offered - 1, &_offered_termination, current_offered)) != expected_value);
+
+ assert(_offered_termination < _n_threads, "Invariant");
+ return false;
+}
+
void ParallelTaskTerminator::reset_for_reuse() {
if (_offered_termination != 0) {
assert(_offered_termination == _n_threads,
diff --git a/src/hotspot/share/gc/shared/taskqueue.hpp b/src/hotspot/share/gc/shared/taskqueue.hpp
index 1b60a62c2..110757684 100644
--- a/src/hotspot/share/gc/shared/taskqueue.hpp
+++ b/src/hotspot/share/gc/shared/taskqueue.hpp
@@ -491,11 +491,18 @@ protected:
virtual void yield();
void sleep(uint millis);
+ // Called when exiting termination is requested.
+ // When the request is made, terminator may have already terminated
+ // (e.g. all threads are arrived and offered termination). In this case,
+ // it should ignore the request and complete the termination.
+ // Return true if termination is completed. Otherwise, return false.
+ bool complete_or_exit_termination();
public:
// "n_threads" is the number of threads to be terminated. "queue_set" is a
// queue sets of work queues of other threads.
ParallelTaskTerminator(uint n_threads, TaskQueueSetSuper* queue_set);
+ virtual ~ParallelTaskTerminator();
// The current thread has no work, and is ready to terminate if everyone
// else is. If returns "true", all threads are terminated. If returns
--
2.19.1
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