1 /*
2 * Copyright (c) 2021, Red Hat, Inc. All rights reserved.
3 * Copyright (c) 2020, 2023, Oracle and/or its affiliates. All rights reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27
28 #include "gc/shenandoah/shenandoahAsserts.hpp"
29 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
30 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
31 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
32 #include "gc/shenandoah/shenandoahStackWatermark.hpp"
33 #include "gc/shenandoah/shenandoahUtils.hpp"
34 #include "runtime/safepointVerifiers.hpp"
35
36 uint32_t ShenandoahStackWatermark::_epoch_id = 1;
37
38 ShenandoahOnStackCodeBlobClosure::ShenandoahOnStackCodeBlobClosure() :
39 _bs_nm(BarrierSet::barrier_set()->barrier_set_nmethod()) {}
40
41 void ShenandoahOnStackCodeBlobClosure::do_code_blob(CodeBlob* cb) {
42 nmethod* const nm = cb->as_nmethod_or_null();
43 if (nm != nullptr) {
44 const bool result = _bs_nm->nmethod_entry_barrier(nm);
45 assert(result, "NMethod on-stack must be alive");
46 }
47 }
48
49 ThreadLocalAllocStats& ShenandoahStackWatermark::stats() {
50 return _stats;
51 }
52
53 uint32_t ShenandoahStackWatermark::epoch_id() const {
54 return _epoch_id;
55 }
56
57 void ShenandoahStackWatermark::change_epoch_id() {
58 shenandoah_assert_safepoint();
59 _epoch_id++;
60 }
61
62 ShenandoahStackWatermark::ShenandoahStackWatermark(JavaThread* jt) :
63 StackWatermark(jt, StackWatermarkKind::gc, _epoch_id),
64 _heap(ShenandoahHeap::heap()),
65 _stats(),
66 _keep_alive_cl(),
67 _evac_update_oop_cl(),
68 _cb_cl() {}
69
70 OopClosure* ShenandoahStackWatermark::closure_from_context(void* context) {
71 if (context != nullptr) {
72 assert(_heap->is_concurrent_weak_root_in_progress() ||
73 _heap->is_concurrent_mark_in_progress(),
74 "Only these two phases");
75 assert(Thread::current()->is_Worker_thread(), "Unexpected thread passing in context: " PTR_FORMAT, p2i(context));
76 return reinterpret_cast<OopClosure*>(context);
77 } else {
78 if (_heap->is_concurrent_mark_in_progress()) {
79 return &_keep_alive_cl;
80 } else if (_heap->is_concurrent_weak_root_in_progress()) {
81 assert(_heap->is_evacuation_in_progress(), "Nothing to evacuate");
82 return &_evac_update_oop_cl;
83 } else {
84 ShouldNotReachHere();
85 return nullptr;
86 }
87 }
88 }
89
90 void ShenandoahStackWatermark::start_processing_impl(void* context) {
91 NoSafepointVerifier nsv;
92 ShenandoahHeap* const heap = ShenandoahHeap::heap();
93
94 // Process the non-frame part of the thread
95 if (heap->is_concurrent_mark_in_progress()) {
96 // We need to reset all TLABs because they might be below the TAMS, and we need to mark
97 // the objects in them. Do not let mutators allocate any new objects in their current TLABs.
98 // It is also a good place to resize the TLAB sizes for future allocations.
99 retire_tlab();
100
101 _jt->oops_do_no_frames(closure_from_context(context), &_cb_cl);
102 } else if (heap->is_concurrent_weak_root_in_progress()) {
103 assert(heap->is_evacuation_in_progress(), "Should not be armed");
104 // Retire the TLABs, which will force threads to reacquire their TLABs.
105 // This is needed for two reasons. Strong one: new allocations would be with new freeset,
106 // which would be outside the collection set, so no cset writes would happen there.
107 // Weaker one: new allocations would happen past update watermark, and so less work would
108 // be needed for reference updates (would update the large filler instead).
109 retire_tlab();
110
111 _jt->oops_do_no_frames(closure_from_context(context), &_cb_cl);
112 } else {
113 ShouldNotReachHere();
114 }
115
116 // Publishes the processing start to concurrent threads
117 StackWatermark::start_processing_impl(context);
118 }
119
120 void ShenandoahStackWatermark::retire_tlab() {
121 // Retire TLAB
122 if (UseTLAB) {
123 _stats.reset();
124 _jt->tlab().retire(&_stats);
125 if (ResizeTLAB) {
126 _jt->tlab().resize();
127 }
128 }
129 }
130
131 void ShenandoahStackWatermark::process(const frame& fr, RegisterMap& register_map, void* context) {
132 OopClosure* oops = closure_from_context(context);
133 assert(oops != nullptr, "Should not get to here");
134 ShenandoahHeap* const heap = ShenandoahHeap::heap();
135 assert((heap->is_concurrent_weak_root_in_progress() && heap->is_evacuation_in_progress()) ||
136 heap->is_concurrent_mark_in_progress(),
137 "Only these two phases");
138 fr.oops_do(oops, &_cb_cl, ®ister_map, DerivedPointerIterationMode::_directly);
139 }