Bug Summary

File:jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp
Warning:line 174, column 14
Called C++ object pointer is null

Annotated Source Code

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clang -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name referenceProcessor.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 2 -mthread-model posix -fno-delete-null-pointer-checks -mframe-pointer=all -relaxed-aliasing -fmath-errno -fno-rounding-math -masm-verbose -mconstructor-aliases -munwind-tables -target-cpu x86-64 -dwarf-column-info -fno-split-dwarf-inlining -debugger-tuning=gdb -resource-dir /usr/lib/llvm-10/lib/clang/10.0.0 -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/hotspot/variant-server/libjvm/objs/precompiled -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -D __STDC_CONSTANT_MACROS -D _GNU_SOURCE -D _REENTRANT -D LIBC=gnu -D LINUX -D VM_LITTLE_ENDIAN -D _LP64=1 -D ASSERT -D CHECK_UNHANDLED_OOPS -D TARGET_ARCH_x86 -D INCLUDE_SUFFIX_OS=_linux -D INCLUDE_SUFFIX_CPU=_x86 -D INCLUDE_SUFFIX_COMPILER=_gcc -D TARGET_COMPILER_gcc -D AMD64 -D HOTSPOT_LIB_ARCH="amd64" -D COMPILER1 -D COMPILER2 -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/hotspot/variant-server/gensrc/adfiles -I /home/daniel/Projects/java/jdk/src/hotspot/share -I /home/daniel/Projects/java/jdk/src/hotspot/os/linux -I /home/daniel/Projects/java/jdk/src/hotspot/os/posix -I /home/daniel/Projects/java/jdk/src/hotspot/cpu/x86 -I /home/daniel/Projects/java/jdk/src/hotspot/os_cpu/linux_x86 -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/hotspot/variant-server/gensrc -I /home/daniel/Projects/java/jdk/src/hotspot/share/precompiled -I /home/daniel/Projects/java/jdk/src/hotspot/share/include -I /home/daniel/Projects/java/jdk/src/hotspot/os/posix/include -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/support/modules_include/java.base -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/support/modules_include/java.base/linux -I /home/daniel/Projects/java/jdk/src/java.base/share/native/libjimage -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/hotspot/variant-server/gensrc/adfiles -I /home/daniel/Projects/java/jdk/src/hotspot/share -I /home/daniel/Projects/java/jdk/src/hotspot/os/linux -I /home/daniel/Projects/java/jdk/src/hotspot/os/posix -I /home/daniel/Projects/java/jdk/src/hotspot/cpu/x86 -I /home/daniel/Projects/java/jdk/src/hotspot/os_cpu/linux_x86 -I /home/daniel/Projects/java/jdk/build/linux-x86_64-server-fastdebug/hotspot/variant-server/gensrc -D _FORTIFY_SOURCE=2 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/c++/7.5.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/x86_64-linux-gnu/c++/7.5.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/x86_64-linux-gnu/c++/7.5.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/7.5.0/../../../../include/c++/7.5.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-10/lib/clang/10.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O3 -Wno-format-zero-length -Wno-unused-parameter -Wno-unused -Wno-parentheses -Wno-comment -Wno-unknown-pragmas -Wno-address -Wno-delete-non-virtual-dtor -Wno-char-subscripts -Wno-array-bounds -Wno-int-in-bool-context -Wno-ignored-qualifiers -Wno-missing-field-initializers -Wno-implicit-fallthrough -Wno-empty-body -Wno-strict-overflow -Wno-sequence-point -Wno-maybe-uninitialized -Wno-misleading-indentation -Wno-cast-function-type -Wno-shift-negative-value -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /home/daniel/Projects/java/jdk/make/hotspot -ferror-limit 19 -fmessage-length 0 -fvisibility hidden -stack-protector 1 -fno-rtti -fgnuc-version=4.2.1 -fobjc-runtime=gcc -fdiagnostics-show-option -vectorize-loops -vectorize-slp -analyzer-output=html -faddrsig -o /home/daniel/Projects/java/scan/2021-12-21-193737-8510-1 -x c++ /home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp
1/*
2 * Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25#include "precompiled.hpp"
26#include "classfile/javaClasses.inline.hpp"
27#include "gc/shared/collectedHeap.hpp"
28#include "gc/shared/collectedHeap.inline.hpp"
29#include "gc/shared/gc_globals.hpp"
30#include "gc/shared/gcTimer.hpp"
31#include "gc/shared/gcTraceTime.inline.hpp"
32#include "gc/shared/referencePolicy.hpp"
33#include "gc/shared/referenceProcessor.inline.hpp"
34#include "gc/shared/referenceProcessorPhaseTimes.hpp"
35#include "logging/log.hpp"
36#include "memory/allocation.inline.hpp"
37#include "memory/resourceArea.hpp"
38#include "memory/universe.hpp"
39#include "oops/access.inline.hpp"
40#include "oops/oop.inline.hpp"
41#include "runtime/java.hpp"
42#include "runtime/nonJavaThread.hpp"
43#include "utilities/globalDefinitions.hpp"
44
45ReferencePolicy* ReferenceProcessor::_always_clear_soft_ref_policy = NULL__null;
46ReferencePolicy* ReferenceProcessor::_default_soft_ref_policy = NULL__null;
47jlong ReferenceProcessor::_soft_ref_timestamp_clock = 0;
48
49void referenceProcessor_init() {
50 ReferenceProcessor::init_statics();
51}
52
53void ReferenceProcessor::init_statics() {
54 // We need a monotonically non-decreasing time in ms but
55 // os::javaTimeMillis() does not guarantee monotonicity.
56 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
57
58 // Initialize the soft ref timestamp clock.
59 _soft_ref_timestamp_clock = now;
60 // Also update the soft ref clock in j.l.r.SoftReference
61 java_lang_ref_SoftReference::set_clock(_soft_ref_timestamp_clock);
62
63 _always_clear_soft_ref_policy = new AlwaysClearPolicy();
64 if (CompilerConfig::is_c2_or_jvmci_compiler_enabled()) {
65 _default_soft_ref_policy = new LRUMaxHeapPolicy();
66 } else {
67 _default_soft_ref_policy = new LRUCurrentHeapPolicy();
68 }
69 guarantee(RefDiscoveryPolicy == ReferenceBasedDiscovery ||do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery || RefDiscoveryPolicy
== ReferentBasedDiscovery)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 71, "guarantee(" "RefDiscoveryPolicy == ReferenceBasedDiscovery || RefDiscoveryPolicy == ReferentBasedDiscovery"
") failed", "Unrecognized RefDiscoveryPolicy"); ::breakpoint
(); } } while (0)
70 RefDiscoveryPolicy == ReferentBasedDiscovery,do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery || RefDiscoveryPolicy
== ReferentBasedDiscovery)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 71, "guarantee(" "RefDiscoveryPolicy == ReferenceBasedDiscovery || RefDiscoveryPolicy == ReferentBasedDiscovery"
") failed", "Unrecognized RefDiscoveryPolicy"); ::breakpoint
(); } } while (0)
71 "Unrecognized RefDiscoveryPolicy")do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery || RefDiscoveryPolicy
== ReferentBasedDiscovery)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 71, "guarantee(" "RefDiscoveryPolicy == ReferenceBasedDiscovery || RefDiscoveryPolicy == ReferentBasedDiscovery"
") failed", "Unrecognized RefDiscoveryPolicy"); ::breakpoint
(); } } while (0);
72}
73
74void ReferenceProcessor::enable_discovery(bool check_no_refs) {
75#ifdef ASSERT1
76 // Verify that we're not currently discovering refs
77 assert(!_discovering_refs, "nested call?")do { if (!(!_discovering_refs)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 77, "assert(" "!_discovering_refs" ") failed", "nested call?"
); ::breakpoint(); } } while (0);
78
79 if (check_no_refs) {
80 // Verify that the discovered lists are empty
81 verify_no_references_recorded();
82 }
83#endif // ASSERT
84
85 _discovering_refs = true;
86}
87
88ReferenceProcessor::ReferenceProcessor(BoolObjectClosure* is_subject_to_discovery,
89 uint mt_processing_degree,
90 uint mt_discovery_degree,
91 bool concurrent_discovery,
92 BoolObjectClosure* is_alive_non_header) :
93 _is_subject_to_discovery(is_subject_to_discovery),
94 _discovering_refs(false),
95 _next_id(0),
96 _is_alive_non_header(is_alive_non_header)
97{
98 assert(is_subject_to_discovery != NULL, "must be set")do { if (!(is_subject_to_discovery != __null)) { (*g_assert_poison
) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 98, "assert(" "is_subject_to_discovery != __null" ") failed"
, "must be set"); ::breakpoint(); } } while (0);
99
100 _discovery_is_concurrent = concurrent_discovery;
101 _discovery_is_mt = (mt_discovery_degree > 1);
102 _num_queues = MAX2(1U, mt_processing_degree);
103 _max_num_queues = MAX2(_num_queues, mt_discovery_degree);
104 _discovered_refs = NEW_C_HEAP_ARRAY(DiscoveredList,(DiscoveredList*) (AllocateHeap((_max_num_queues * number_of_subclasses_of_ref
()) * sizeof(DiscoveredList), mtGC))
105 _max_num_queues * number_of_subclasses_of_ref(), mtGC)(DiscoveredList*) (AllocateHeap((_max_num_queues * number_of_subclasses_of_ref
()) * sizeof(DiscoveredList), mtGC));
106
107 _discoveredSoftRefs = &_discovered_refs[0];
108 _discoveredWeakRefs = &_discoveredSoftRefs[_max_num_queues];
109 _discoveredFinalRefs = &_discoveredWeakRefs[_max_num_queues];
110 _discoveredPhantomRefs = &_discoveredFinalRefs[_max_num_queues];
111
112 // Initialize all entries to NULL
113 for (uint i = 0; i < _max_num_queues * number_of_subclasses_of_ref(); i++) {
114 _discovered_refs[i].clear();
115 }
116
117 setup_policy(false /* default soft ref policy */);
118}
119
120#ifndef PRODUCT
121void ReferenceProcessor::verify_no_references_recorded() {
122 guarantee(!_discovering_refs, "Discovering refs?")do { if (!(!_discovering_refs)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 122, "guarantee(" "!_discovering_refs" ") failed", "Discovering refs?"
); ::breakpoint(); } } while (0);
123 for (uint i = 0; i < _max_num_queues * number_of_subclasses_of_ref(); i++) {
124 guarantee(_discovered_refs[i].is_empty(),do { if (!(_discovered_refs[i].is_empty())) { (*g_assert_poison
) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 125, "guarantee(" "_discovered_refs[i].is_empty()" ") failed"
, "Found non-empty discovered list at %u", i); ::breakpoint()
; } } while (0)
125 "Found non-empty discovered list at %u", i)do { if (!(_discovered_refs[i].is_empty())) { (*g_assert_poison
) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 125, "guarantee(" "_discovered_refs[i].is_empty()" ") failed"
, "Found non-empty discovered list at %u", i); ::breakpoint()
; } } while (0);
126 }
127}
128#endif
129
130bool ReferenceProcessor::processing_is_mt() const {
131 return ParallelRefProcEnabled && _num_queues > 1;
132}
133
134void ReferenceProcessor::weak_oops_do(OopClosure* f) {
135 for (uint i = 0; i < _max_num_queues * number_of_subclasses_of_ref(); i++) {
136 if (UseCompressedOops) {
137 f->do_oop((narrowOop*)_discovered_refs[i].adr_head());
138 } else {
139 f->do_oop((oop*)_discovered_refs[i].adr_head());
140 }
141 }
142}
143
144void ReferenceProcessor::update_soft_ref_master_clock() {
145 // Update (advance) the soft ref master clock field. This must be done
146 // after processing the soft ref list.
147
148 // We need a monotonically non-decreasing time in ms but
149 // os::javaTimeMillis() does not guarantee monotonicity.
150 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
151
152 NOT_PRODUCT(if (now < _soft_ref_timestamp_clock) { (!(LogImpl<(LogTag
::_gc), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::is_level(LogLevel
::Warning))) ? (void)0 : LogImpl<(LogTag::_gc), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)>::write<LogLevel::Warning>("time warp: "
"%" "l" "d" " to " "%" "l" "d", _soft_ref_timestamp_clock, now
); }
153 if (now < _soft_ref_timestamp_clock) {if (now < _soft_ref_timestamp_clock) { (!(LogImpl<(LogTag
::_gc), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::is_level(LogLevel
::Warning))) ? (void)0 : LogImpl<(LogTag::_gc), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)>::write<LogLevel::Warning>("time warp: "
"%" "l" "d" " to " "%" "l" "d", _soft_ref_timestamp_clock, now
); }
154 log_warning(gc)("time warp: " JLONG_FORMAT " to " JLONG_FORMAT,if (now < _soft_ref_timestamp_clock) { (!(LogImpl<(LogTag
::_gc), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::is_level(LogLevel
::Warning))) ? (void)0 : LogImpl<(LogTag::_gc), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)>::write<LogLevel::Warning>("time warp: "
"%" "l" "d" " to " "%" "l" "d", _soft_ref_timestamp_clock, now
); }
155 _soft_ref_timestamp_clock, now);if (now < _soft_ref_timestamp_clock) { (!(LogImpl<(LogTag
::_gc), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::is_level(LogLevel
::Warning))) ? (void)0 : LogImpl<(LogTag::_gc), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)>::write<LogLevel::Warning>("time warp: "
"%" "l" "d" " to " "%" "l" "d", _soft_ref_timestamp_clock, now
); }
156 }if (now < _soft_ref_timestamp_clock) { (!(LogImpl<(LogTag
::_gc), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::is_level(LogLevel
::Warning))) ? (void)0 : LogImpl<(LogTag::_gc), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)>::write<LogLevel::Warning>("time warp: "
"%" "l" "d" " to " "%" "l" "d", _soft_ref_timestamp_clock, now
); }
157 )if (now < _soft_ref_timestamp_clock) { (!(LogImpl<(LogTag
::_gc), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::is_level(LogLevel
::Warning))) ? (void)0 : LogImpl<(LogTag::_gc), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)>::write<LogLevel::Warning>("time warp: "
"%" "l" "d" " to " "%" "l" "d", _soft_ref_timestamp_clock, now
); }
158 // The values of now and _soft_ref_timestamp_clock are set using
159 // javaTimeNanos(), which is guaranteed to be monotonically
160 // non-decreasing provided the underlying platform provides such
161 // a time source (and it is bug free).
162 // In product mode, however, protect ourselves from non-monotonicity.
163 if (now > _soft_ref_timestamp_clock) {
164 _soft_ref_timestamp_clock = now;
165 java_lang_ref_SoftReference::set_clock(now);
166 }
167 // Else leave clock stalled at its old value until time progresses
168 // past clock value.
169}
170
171size_t ReferenceProcessor::total_count(DiscoveredList lists[]) const {
172 size_t total = 0;
173 for (uint i = 0; i < _max_num_queues; ++i) {
6
←
Assuming 'i' is < field '_max_num_queues'
→
7
←
Loop condition is true. Entering loop body
→
174 total += lists[i].length();
8
←
Called C++ object pointer is null
175 }
176 return total;
177}
178
179#ifdef ASSERT1
180void ReferenceProcessor::verify_total_count_zero(DiscoveredList lists[], const char* type) {
181 size_t count = total_count(lists);
182 assert(count == 0, "%ss must be empty but has " SIZE_FORMAT " elements", type, count)do { if (!(count == 0)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 182, "assert(" "count == 0" ") failed", "%ss must be empty but has "
"%" "l" "u" " elements", type, count); ::breakpoint(); } } while
(0);
183}
184#endif
185
186ReferenceProcessorStats ReferenceProcessor::process_discovered_references(RefProcProxyTask& proxy_task,
187 ReferenceProcessorPhaseTimes& phase_times) {
188
189 double start_time = os::elapsedTime();
190
191 // Stop treating discovered references specially.
192 disable_discovery();
193
194 phase_times.set_ref_discovered(REF_SOFT, total_count(_discoveredSoftRefs));
195 phase_times.set_ref_discovered(REF_WEAK, total_count(_discoveredWeakRefs));
196 phase_times.set_ref_discovered(REF_FINAL, total_count(_discoveredFinalRefs));
197 phase_times.set_ref_discovered(REF_PHANTOM, total_count(_discoveredPhantomRefs));
198
199 update_soft_ref_master_clock();
200
201 phase_times.set_processing_is_mt(processing_is_mt());
202
203 {
204 RefProcTotalPhaseTimesTracker tt(SoftWeakFinalRefsPhase, &phase_times);
205 process_soft_weak_final_refs(proxy_task, phase_times);
206 }
207
208 {
209 RefProcTotalPhaseTimesTracker tt(KeepAliveFinalRefsPhase, &phase_times);
210 process_final_keep_alive(proxy_task, phase_times);
211 }
212
213 {
214 RefProcTotalPhaseTimesTracker tt(PhantomRefsPhase, &phase_times);
215 process_phantom_refs(proxy_task, phase_times);
216 }
217
218 phase_times.set_total_time_ms((os::elapsedTime() - start_time) * 1000);
219
220 // Elements on discovered lists were pushed to the pending list.
221 verify_no_references_recorded();
222
223 ReferenceProcessorStats stats(phase_times.ref_discovered(REF_SOFT),
224 phase_times.ref_discovered(REF_WEAK),
225 phase_times.ref_discovered(REF_FINAL),
226 phase_times.ref_discovered(REF_PHANTOM));
227 return stats;
228}
229
230void BarrierEnqueueDiscoveredFieldClosure::enqueue(HeapWord* discovered_field_addr, oop value) {
231 assert(Universe::heap()->is_in(discovered_field_addr), PTR_FORMAT " not in heap", p2i(discovered_field_addr))do { if (!(Universe::heap()->is_in(discovered_field_addr))
) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 231, "assert(" "Universe::heap()->is_in(discovered_field_addr)"
") failed", "0x%016" "l" "x" " not in heap", p2i(discovered_field_addr
)); ::breakpoint(); } } while (0);
232 HeapAccess<AS_NO_KEEPALIVE>::oop_store(discovered_field_addr,
233 value);
234}
235
236void DiscoveredListIterator::load_ptrs(DEBUG_ONLY(bool allow_null_referent)bool allow_null_referent) {
237 _current_discovered_addr = java_lang_ref_Reference::discovered_addr_raw(_current_discovered);
238 oop discovered = java_lang_ref_Reference::discovered(_current_discovered);
239 assert(_current_discovered_addr && oopDesc::is_oop_or_null(discovered),do { if (!(_current_discovered_addr && oopDesc::is_oop_or_null
(discovered))) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 240, "assert(" "_current_discovered_addr && oopDesc::is_oop_or_null(discovered)"
") failed", "Expected an oop or NULL for discovered field at "
"0x%016" "l" "x", p2i(discovered)); ::breakpoint(); } } while
(0)
240 "Expected an oop or NULL for discovered field at " PTR_FORMAT, p2i(discovered))do { if (!(_current_discovered_addr && oopDesc::is_oop_or_null
(discovered))) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 240, "assert(" "_current_discovered_addr && oopDesc::is_oop_or_null(discovered)"
") failed", "Expected an oop or NULL for discovered field at "
"0x%016" "l" "x", p2i(discovered)); ::breakpoint(); } } while
(0);
241 _next_discovered = discovered;
242 _referent = java_lang_ref_Reference::unknown_referent_no_keepalive(_current_discovered);
243 assert(Universe::heap()->is_in_or_null(_referent),do { if (!(Universe::heap()->is_in_or_null(_referent))) { (
*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 244, "assert(" "Universe::heap()->is_in_or_null(_referent)"
") failed", "Wrong oop found in java.lang.Reference object")
; ::breakpoint(); } } while (0)
244 "Wrong oop found in java.lang.Reference object")do { if (!(Universe::heap()->is_in_or_null(_referent))) { (
*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 244, "assert(" "Universe::heap()->is_in_or_null(_referent)"
") failed", "Wrong oop found in java.lang.Reference object")
; ::breakpoint(); } } while (0);
245 assert(allow_null_referent ?do { if (!(allow_null_referent ? oopDesc::is_oop_or_null(_referent
) : oopDesc::is_oop(_referent))) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 250, "assert(" "allow_null_referent ? oopDesc::is_oop_or_null(_referent) : oopDesc::is_oop(_referent)"
") failed", "Expected an oop%s for referent field at " "0x%016"
"l" "x", (allow_null_referent ? " or NULL" : ""), p2i(_referent
)); ::breakpoint(); } } while (0)
246 oopDesc::is_oop_or_null(_referent)do { if (!(allow_null_referent ? oopDesc::is_oop_or_null(_referent
) : oopDesc::is_oop(_referent))) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 250, "assert(" "allow_null_referent ? oopDesc::is_oop_or_null(_referent) : oopDesc::is_oop(_referent)"
") failed", "Expected an oop%s for referent field at " "0x%016"
"l" "x", (allow_null_referent ? " or NULL" : ""), p2i(_referent
)); ::breakpoint(); } } while (0)
247 : oopDesc::is_oop(_referent),do { if (!(allow_null_referent ? oopDesc::is_oop_or_null(_referent
) : oopDesc::is_oop(_referent))) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 250, "assert(" "allow_null_referent ? oopDesc::is_oop_or_null(_referent) : oopDesc::is_oop(_referent)"
") failed", "Expected an oop%s for referent field at " "0x%016"
"l" "x", (allow_null_referent ? " or NULL" : ""), p2i(_referent
)); ::breakpoint(); } } while (0)
248 "Expected an oop%s for referent field at " PTR_FORMAT,do { if (!(allow_null_referent ? oopDesc::is_oop_or_null(_referent
) : oopDesc::is_oop(_referent))) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 250, "assert(" "allow_null_referent ? oopDesc::is_oop_or_null(_referent) : oopDesc::is_oop(_referent)"
") failed", "Expected an oop%s for referent field at " "0x%016"
"l" "x", (allow_null_referent ? " or NULL" : ""), p2i(_referent
)); ::breakpoint(); } } while (0)
249 (allow_null_referent ? " or NULL" : ""),do { if (!(allow_null_referent ? oopDesc::is_oop_or_null(_referent
) : oopDesc::is_oop(_referent))) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 250, "assert(" "allow_null_referent ? oopDesc::is_oop_or_null(_referent) : oopDesc::is_oop(_referent)"
") failed", "Expected an oop%s for referent field at " "0x%016"
"l" "x", (allow_null_referent ? " or NULL" : ""), p2i(_referent
)); ::breakpoint(); } } while (0)
250 p2i(_referent))do { if (!(allow_null_referent ? oopDesc::is_oop_or_null(_referent
) : oopDesc::is_oop(_referent))) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 250, "assert(" "allow_null_referent ? oopDesc::is_oop_or_null(_referent) : oopDesc::is_oop(_referent)"
") failed", "Expected an oop%s for referent field at " "0x%016"
"l" "x", (allow_null_referent ? " or NULL" : ""), p2i(_referent
)); ::breakpoint(); } } while (0);
251}
252
253void DiscoveredListIterator::remove() {
254 assert(oopDesc::is_oop(_current_discovered), "Dropping a bad reference")do { if (!(oopDesc::is_oop(_current_discovered))) { (*g_assert_poison
) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 254, "assert(" "oopDesc::is_oop(_current_discovered)" ") failed"
, "Dropping a bad reference"); ::breakpoint(); } } while (0);
255 RawAccess<>::oop_store(_current_discovered_addr, oop(NULL__null));
256
257 // First _prev_next ref actually points into DiscoveredList (gross).
258 oop new_next;
259 if (_next_discovered == _current_discovered) {
260 // At the end of the list, we should make _prev point to itself.
261 // If _ref is the first ref, then _prev_next will be in the DiscoveredList,
262 // and _prev will be NULL.
263 new_next = _prev_discovered;
264 } else {
265 new_next = _next_discovered;
266 }
267 // Remove Reference object from discovered list. We do not need barriers here,
268 // as we only remove. We will do the barrier when we actually advance the cursor.
269 RawAccess<>::oop_store(_prev_discovered_addr, new_next);
270 _removed++;
271 _refs_list.dec_length(1);
272}
273
274void DiscoveredListIterator::make_referent_alive() {
275 HeapWord* addr = java_lang_ref_Reference::referent_addr_raw(_current_discovered);
276 if (UseCompressedOops) {
277 _keep_alive->do_oop((narrowOop*)addr);
278 } else {
279 _keep_alive->do_oop((oop*)addr);
280 }
281}
282
283void DiscoveredListIterator::clear_referent() {
284 java_lang_ref_Reference::clear_referent(_current_discovered);
285}
286
287void DiscoveredListIterator::enqueue() {
288 if (_prev_discovered_addr != _refs_list.adr_head()) {
289 _enqueue->enqueue(_prev_discovered_addr, _current_discovered);
290 } else {
291 RawAccess<>::oop_store(_prev_discovered_addr, _current_discovered);
292 }
293}
294
295void DiscoveredListIterator::complete_enqueue() {
296 if (_prev_discovered != nullptr) {
297 // This is the last object.
298 // Swap refs_list into pending list and set obj's
299 // discovered to what we read from the pending list.
300 oop old = Universe::swap_reference_pending_list(_refs_list.head());
301 _enqueue->enqueue(java_lang_ref_Reference::discovered_addr_raw(_prev_discovered), old);
302 }
303}
304
305inline void log_preclean_ref(const DiscoveredListIterator& iter, const char* reason) {
306 if (log_develop_is_enabled(Trace, gc, ref)(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>
::is_level(LogLevel::Trace))) {
307 ResourceMark rm;
308 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Precleaning %s reference " PTR_FORMAT"0x%016" "l" "x" ": %s",
309 reason, p2i(iter.obj()),
310 iter.obj()->klass()->internal_name());
311 }
312}
313
314inline void log_dropped_ref(const DiscoveredListIterator& iter, const char* reason) {
315 if (log_develop_is_enabled(Trace, gc, ref)(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>
::is_level(LogLevel::Trace))) {
316 ResourceMark rm;
317 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Dropping %s reference " PTR_FORMAT"0x%016" "l" "x" ": %s",
318 reason, p2i(iter.obj()),
319 iter.obj()->klass()->internal_name());
320 }
321}
322
323inline void log_enqueued_ref(const DiscoveredListIterator& iter, const char* reason) {
324 if (log_develop_is_enabled(Trace, gc, ref)(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>
::is_level(LogLevel::Trace))) {
325 ResourceMark rm;
326 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Enqueue %s reference (" INTPTR_FORMAT"0x%016" "l" "x" ": %s)",
327 reason, p2i(iter.obj()), iter.obj()->klass()->internal_name());
328 }
329 assert(oopDesc::is_oop(iter.obj()), "Adding a bad reference")do { if (!(oopDesc::is_oop(iter.obj()))) { (*g_assert_poison)
= 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 329, "assert(" "oopDesc::is_oop(iter.obj())" ") failed", "Adding a bad reference"
); ::breakpoint(); } } while (0);
330}
331
332size_t ReferenceProcessor::process_discovered_list_work(DiscoveredList& refs_list,
333 BoolObjectClosure* is_alive,
334 OopClosure* keep_alive,
335 EnqueueDiscoveredFieldClosure* enqueue,
336 bool do_enqueue_and_clear) {
337 DiscoveredListIterator iter(refs_list, keep_alive, is_alive, enqueue);
338 while (iter.has_next()) {
339 iter.load_ptrs(DEBUG_ONLY(discovery_is_concurrent() /* allow_null_referent */)discovery_is_concurrent());
340 if (iter.referent() == NULL__null) {
341 // Reference has been cleared since discovery; only possible if
342 // discovery is concurrent (checked by load_ptrs). Remove
343 // reference from list.
344 log_dropped_ref(iter, "cleared");
345 iter.remove();
346 iter.move_to_next();
347 } else if (iter.is_referent_alive()) {
348 // The referent is reachable after all.
349 // Remove reference from list.
350 log_dropped_ref(iter, "reachable");
351 iter.remove();
352 // Update the referent pointer as necessary. Note that this
353 // should not entail any recursive marking because the
354 // referent must already have been traversed.
355 iter.make_referent_alive();
356 iter.move_to_next();
357 } else {
358 if (do_enqueue_and_clear) {
359 iter.clear_referent();
360 iter.enqueue();
361 log_enqueued_ref(iter, "cleared");
362 }
363 // Keep in discovered list
364 iter.next();
365 }
366 }
367 if (do_enqueue_and_clear) {
368 iter.complete_enqueue();
369 refs_list.clear();
370 }
371
372 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>(" Dropped " SIZE_FORMAT"%" "l" "u" " active Refs out of " SIZE_FORMAT"%" "l" "u"
373 " Refs in discovered list " INTPTR_FORMAT"0x%016" "l" "x",
374 iter.removed(), iter.processed(), p2i(&refs_list));
375 return iter.removed();
376}
377
378size_t ReferenceProcessor::process_final_keep_alive_work(DiscoveredList& refs_list,
379 OopClosure* keep_alive,
380 EnqueueDiscoveredFieldClosure* enqueue) {
381 DiscoveredListIterator iter(refs_list, keep_alive, NULL__null, enqueue);
382 while (iter.has_next()) {
383 iter.load_ptrs(DEBUG_ONLY(false /* allow_null_referent */)false);
384 // keep the referent and followers around
385 iter.make_referent_alive();
386
387 // Self-loop next, to mark the FinalReference not active.
388 assert(java_lang_ref_Reference::next(iter.obj()) == NULL, "enqueued FinalReference")do { if (!(java_lang_ref_Reference::next(iter.obj()) == __null
)) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 388, "assert(" "java_lang_ref_Reference::next(iter.obj()) == __null"
") failed", "enqueued FinalReference"); ::breakpoint(); } } while
(0);
389 java_lang_ref_Reference::set_next_raw(iter.obj(), iter.obj());
390
391 iter.enqueue();
392 log_enqueued_ref(iter, "Final");
393 iter.next();
394 }
395 iter.complete_enqueue();
396 refs_list.clear();
397
398 assert(iter.removed() == 0, "This phase does not remove anything.")do { if (!(iter.removed() == 0)) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 398, "assert(" "iter.removed() == 0" ") failed", "This phase does not remove anything."
); ::breakpoint(); } } while (0);
399 return iter.removed();
400}
401
402void
403ReferenceProcessor::clear_discovered_references(DiscoveredList& refs_list) {
404 oop obj = NULL__null;
405 oop next = refs_list.head();
406 while (next != obj) {
407 obj = next;
408 next = java_lang_ref_Reference::discovered(obj);
409 java_lang_ref_Reference::set_discovered_raw(obj, NULL__null);
410 }
411 refs_list.clear();
412}
413
414void ReferenceProcessor::abandon_partial_discovery() {
415 // loop over the lists
416 for (uint i = 0; i < _max_num_queues * number_of_subclasses_of_ref(); i++) {
417 if ((i % _max_num_queues) == 0) {
418 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Abandoning %s discovered list", list_name(i));
419 }
420 clear_discovered_references(_discovered_refs[i]);
421 }
422}
423
424size_t ReferenceProcessor::total_reference_count(ReferenceType type) const {
425 DiscoveredList* list = NULL__null;
1
'list' initialized to a null pointer value
→
426
427 switch (type) {
2
←
Control jumps to 'case REF_NONE:' at line 441
→
428 case REF_SOFT:
429 list = _discoveredSoftRefs;
430 break;
431 case REF_WEAK:
432 list = _discoveredWeakRefs;
433 break;
434 case REF_FINAL:
435 list = _discoveredFinalRefs;
436 break;
437 case REF_PHANTOM:
438 list = _discoveredPhantomRefs;
439 break;
440 case REF_OTHER:
441 case REF_NONE:
442 default:
443 ShouldNotReachHere()do { (*g_assert_poison) = 'X';; report_should_not_reach_here(
"/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 443); ::breakpoint(); } while (0);
3
←
Loop condition is false. Exiting loop
→
444 }
445 return total_count(list);
4
←
Passing null pointer value via 1st parameter 'lists'
→
5
←
Calling 'ReferenceProcessor::total_count'
→
446}
447
448void RefProcTask::process_discovered_list(uint worker_id,
449 ReferenceType ref_type,
450 BoolObjectClosure* is_alive,
451 OopClosure* keep_alive,
452 EnqueueDiscoveredFieldClosure* enqueue) {
453 ReferenceProcessor::RefProcSubPhases subphase;
454 DiscoveredList* dl;
455 switch (ref_type) {
456 case ReferenceType::REF_SOFT:
457 subphase = ReferenceProcessor::ProcessSoftRefSubPhase;
458 dl = _ref_processor._discoveredSoftRefs;
459 break;
460 case ReferenceType::REF_WEAK:
461 subphase = ReferenceProcessor::ProcessWeakRefSubPhase;
462 dl = _ref_processor._discoveredWeakRefs;
463 break;
464 case ReferenceType::REF_FINAL:
465 subphase = ReferenceProcessor::ProcessFinalRefSubPhase;
466 dl = _ref_processor._discoveredFinalRefs;
467 break;
468 case ReferenceType::REF_PHANTOM:
469 subphase = ReferenceProcessor::ProcessPhantomRefsSubPhase;
470 dl = _ref_processor._discoveredPhantomRefs;
471 break;
472 default:
473 ShouldNotReachHere()do { (*g_assert_poison) = 'X';; report_should_not_reach_here(
"/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 473); ::breakpoint(); } while (0);
474 }
475
476 // Only Final refs are not enqueued and cleared here.
477 bool do_enqueue_and_clear = (ref_type != REF_FINAL);
478
479 {
480 RefProcSubPhasesWorkerTimeTracker tt(subphase, _phase_times, tracker_id(worker_id));
481 size_t const removed = _ref_processor.process_discovered_list_work(dl[worker_id],
482 is_alive,
483 keep_alive,
484 enqueue,
485 do_enqueue_and_clear);
486 _phase_times->add_ref_cleared(ref_type, removed);
487 }
488}
489
490class RefProcSoftWeakFinalPhaseTask: public RefProcTask {
491public:
492 RefProcSoftWeakFinalPhaseTask(ReferenceProcessor& ref_processor,
493 ReferenceProcessorPhaseTimes* phase_times)
494 : RefProcTask(ref_processor,
495 phase_times) {}
496
497 void rp_work(uint worker_id,
498 BoolObjectClosure* is_alive,
499 OopClosure* keep_alive,
500 EnqueueDiscoveredFieldClosure* enqueue,
501 VoidClosure* complete_gc) override {
502 RefProcWorkerTimeTracker t(_phase_times->soft_weak_final_refs_phase_worker_time_sec(), tracker_id(worker_id));
503
504 process_discovered_list(worker_id, REF_SOFT, is_alive, keep_alive, enqueue);
505
506 process_discovered_list(worker_id, REF_WEAK, is_alive, keep_alive, enqueue);
507
508 process_discovered_list(worker_id, REF_FINAL, is_alive, keep_alive, enqueue);
509
510 // Close the reachable set; needed for collectors which keep_alive_closure do
511 // not immediately complete their work.
512 complete_gc->do_void();
513 }
514};
515
516class RefProcKeepAliveFinalPhaseTask: public RefProcTask {
517public:
518 RefProcKeepAliveFinalPhaseTask(ReferenceProcessor& ref_processor,
519 ReferenceProcessorPhaseTimes* phase_times)
520 : RefProcTask(ref_processor,
521 phase_times) {}
522
523 void rp_work(uint worker_id,
524 BoolObjectClosure* is_alive,
525 OopClosure* keep_alive,
526 EnqueueDiscoveredFieldClosure* enqueue,
527 VoidClosure* complete_gc) override {
528 RefProcSubPhasesWorkerTimeTracker tt(ReferenceProcessor::KeepAliveFinalRefsSubPhase, _phase_times, tracker_id(worker_id));
529 _ref_processor.process_final_keep_alive_work(_ref_processor._discoveredFinalRefs[worker_id], keep_alive, enqueue);
530 // Close the reachable set
531 complete_gc->do_void();
532 }
533};
534
535class RefProcPhantomPhaseTask: public RefProcTask {
536public:
537 RefProcPhantomPhaseTask(ReferenceProcessor& ref_processor,
538 ReferenceProcessorPhaseTimes* phase_times)
539 : RefProcTask(ref_processor,
540 phase_times) {}
541
542 void rp_work(uint worker_id,
543 BoolObjectClosure* is_alive,
544 OopClosure* keep_alive,
545 EnqueueDiscoveredFieldClosure* enqueue,
546 VoidClosure* complete_gc) override {
547 process_discovered_list(worker_id, REF_PHANTOM, is_alive, keep_alive, enqueue);
548
549 // Close the reachable set; needed for collectors which keep_alive_closure do
550 // not immediately complete their work.
551 complete_gc->do_void();
552 }
553};
554
555void ReferenceProcessor::log_reflist(const char* prefix, DiscoveredList list[], uint num_active_queues) {
556 LogTarget(Trace, gc, ref)LogTargetImpl<LogLevel::Trace, (LogTag::_gc), (LogTag::_ref
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG)> lt;
557
558 if (!lt.is_enabled()) {
559 return;
560 }
561
562 size_t total = 0;
563
564 LogStream ls(lt);
565 ls.print("%s", prefix);
566 for (uint i = 0; i < num_active_queues; i++) {
567 ls.print(SIZE_FORMAT"%" "l" "u" " ", list[i].length());
568 total += list[i].length();
569 }
570 ls.print_cr("(" SIZE_FORMAT"%" "l" "u" ")", total);
571}
572
573#ifndef PRODUCT
574void ReferenceProcessor::log_reflist_counts(DiscoveredList ref_lists[], uint num_active_queues) {
575 if (!log_is_enabled(Trace, gc, ref)(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG)
, (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>
::is_level(LogLevel::Trace))) {
576 return;
577 }
578
579 log_reflist("", ref_lists, num_active_queues);
580#ifdef ASSERT1
581 for (uint i = num_active_queues; i < _max_num_queues; i++) {
582 assert(ref_lists[i].length() == 0, SIZE_FORMAT " unexpected References in %u",do { if (!(ref_lists[i].length() == 0)) { (*g_assert_poison) =
'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 583, "assert(" "ref_lists[i].length() == 0" ") failed", "%"
"l" "u" " unexpected References in %u", ref_lists[i].length(
), i); ::breakpoint(); } } while (0)
583 ref_lists[i].length(), i)do { if (!(ref_lists[i].length() == 0)) { (*g_assert_poison) =
'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 583, "assert(" "ref_lists[i].length() == 0" ") failed", "%"
"l" "u" " unexpected References in %u", ref_lists[i].length(
), i); ::breakpoint(); } } while (0);
584 }
585#endif
586}
587#endif
588
589void ReferenceProcessor::set_active_mt_degree(uint v) {
590 assert(v <= max_num_queues(), "Mt degree %u too high, maximum %u", v, max_num_queues())do { if (!(v <= max_num_queues())) { (*g_assert_poison) = 'X'
;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 590, "assert(" "v <= max_num_queues()" ") failed", "Mt degree %u too high, maximum %u"
, v, max_num_queues()); ::breakpoint(); } } while (0);
591 _num_queues = v;
592 _next_id = 0;
593}
594
595bool ReferenceProcessor::need_balance_queues(DiscoveredList refs_lists[]) {
596 assert(processing_is_mt(), "why balance non-mt processing?")do { if (!(processing_is_mt())) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 596, "assert(" "processing_is_mt()" ") failed", "why balance non-mt processing?"
); ::breakpoint(); } } while (0);
597 // _num_queues is the processing degree. Only list entries up to
598 // _num_queues will be processed, so any non-empty lists beyond
599 // that must be redistributed to lists in that range. Even if not
600 // needed for that, balancing may be desirable to eliminate poor
601 // distribution of references among the lists.
602 if (ParallelRefProcBalancingEnabled) {
603 return true; // Configuration says do it.
604 } else {
605 // Configuration says don't balance, but if there are non-empty
606 // lists beyond the processing degree, then must ignore the
607 // configuration and balance anyway.
608 for (uint i = _num_queues; i < _max_num_queues; ++i) {
609 if (!refs_lists[i].is_empty()) {
610 return true; // Must balance despite configuration.
611 }
612 }
613 return false; // Safe to obey configuration and not balance.
614 }
615}
616
617void ReferenceProcessor::maybe_balance_queues(DiscoveredList refs_lists[]) {
618 assert(processing_is_mt(), "Should not call this otherwise")do { if (!(processing_is_mt())) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 618, "assert(" "processing_is_mt()" ") failed", "Should not call this otherwise"
); ::breakpoint(); } } while (0);
619 if (need_balance_queues(refs_lists)) {
620 balance_queues(refs_lists);
621 }
622}
623
624// Balances reference queues.
625// Move entries from all queues[0, 1, ..., _max_num_q-1] to
626// queues[0, 1, ..., _num_q-1] because only the first _num_q
627// corresponding to the active workers will be processed.
628void ReferenceProcessor::balance_queues(DiscoveredList ref_lists[])
629{
630 // calculate total length
631 size_t total_refs = 0;
632 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Balance ref_lists ");
633
634 log_reflist_counts(ref_lists, _max_num_queues);
635
636 for (uint i = 0; i < _max_num_queues; ++i) {
637 total_refs += ref_lists[i].length();
638 }
639 size_t avg_refs = total_refs / _num_queues + 1;
640 uint to_idx = 0;
641 for (uint from_idx = 0; from_idx < _max_num_queues; from_idx++) {
642 bool move_all = false;
643 if (from_idx >= _num_queues) {
644 move_all = ref_lists[from_idx].length() > 0;
645 }
646 while ((ref_lists[from_idx].length() > avg_refs) ||
647 move_all) {
648 assert(to_idx < _num_queues, "Sanity Check!")do { if (!(to_idx < _num_queues)) { (*g_assert_poison) = 'X'
;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 648, "assert(" "to_idx < _num_queues" ") failed", "Sanity Check!"
); ::breakpoint(); } } while (0);
649 if (ref_lists[to_idx].length() < avg_refs) {
650 // move superfluous refs
651 size_t refs_to_move;
652 // Move all the Ref's if the from queue will not be processed.
653 if (move_all) {
654 refs_to_move = MIN2(ref_lists[from_idx].length(),
655 avg_refs - ref_lists[to_idx].length());
656 } else {
657 refs_to_move = MIN2(ref_lists[from_idx].length() - avg_refs,
658 avg_refs - ref_lists[to_idx].length());
659 }
660
661 assert(refs_to_move > 0, "otherwise the code below will fail")do { if (!(refs_to_move > 0)) { (*g_assert_poison) = 'X';;
report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 661, "assert(" "refs_to_move > 0" ") failed", "otherwise the code below will fail"
); ::breakpoint(); } } while (0);
662
663 oop move_head = ref_lists[from_idx].head();
664 oop move_tail = move_head;
665 oop new_head = move_head;
666 // find an element to split the list on
667 for (size_t j = 0; j < refs_to_move; ++j) {
668 move_tail = new_head;
669 new_head = java_lang_ref_Reference::discovered(new_head);
670 }
671
672 // Add the chain to the to list.
673 if (ref_lists[to_idx].head() == NULL__null) {
674 // to list is empty. Make a loop at the end.
675 java_lang_ref_Reference::set_discovered_raw(move_tail, move_tail);
676 } else {
677 java_lang_ref_Reference::set_discovered_raw(move_tail, ref_lists[to_idx].head());
678 }
679 ref_lists[to_idx].set_head(move_head);
680 ref_lists[to_idx].inc_length(refs_to_move);
681
682 // Remove the chain from the from list.
683 if (move_tail == new_head) {
684 // We found the end of the from list.
685 ref_lists[from_idx].set_head(NULL__null);
686 } else {
687 ref_lists[from_idx].set_head(new_head);
688 }
689 ref_lists[from_idx].dec_length(refs_to_move);
690 if (ref_lists[from_idx].length() == 0) {
691 break;
692 }
693 } else {
694 to_idx = (to_idx + 1) % _num_queues;
695 }
696 }
697 }
698#ifdef ASSERT1
699 log_reflist_counts(ref_lists, _num_queues);
700 size_t balanced_total_refs = 0;
701 for (uint i = 0; i < _num_queues; ++i) {
702 balanced_total_refs += ref_lists[i].length();
703 }
704 assert(total_refs == balanced_total_refs, "Balancing was incomplete")do { if (!(total_refs == balanced_total_refs)) { (*g_assert_poison
) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 704, "assert(" "total_refs == balanced_total_refs" ") failed"
, "Balancing was incomplete"); ::breakpoint(); } } while (0);
705#endif
706}
707
708void ReferenceProcessor::run_task(RefProcTask& task, RefProcProxyTask& proxy_task, bool marks_oops_alive) {
709 log_debug(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Debug))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Debug>("ReferenceProcessor::execute queues: %d, %s, marks_oops_alive: %s",
710 num_queues(),
711 processing_is_mt() ? "RefProcThreadModel::Multi" : "RefProcThreadModel::Single",
712 marks_oops_alive ? "true" : "false");
713
714 proxy_task.prepare_run_task(task, num_queues(), processing_is_mt() ? RefProcThreadModel::Multi : RefProcThreadModel::Single, marks_oops_alive);
715 if (processing_is_mt()) {
716 WorkerThreads* workers = Universe::heap()->safepoint_workers();
717 assert(workers != NULL, "can not dispatch multi threaded without workers")do { if (!(workers != __null)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 717, "assert(" "workers != __null" ") failed", "can not dispatch multi threaded without workers"
); ::breakpoint(); } } while (0);
718 assert(workers->active_workers() >= num_queues(),do { if (!(workers->active_workers() >= num_queues())) {
(*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 720, "assert(" "workers->active_workers() >= num_queues()"
") failed", "Ergonomically chosen workers(%u) should be less than or equal to active workers(%u)"
, num_queues(), workers->active_workers()); ::breakpoint()
; } } while (0)
719 "Ergonomically chosen workers(%u) should be less than or equal to active workers(%u)",do { if (!(workers->active_workers() >= num_queues())) {
(*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 720, "assert(" "workers->active_workers() >= num_queues()"
") failed", "Ergonomically chosen workers(%u) should be less than or equal to active workers(%u)"
, num_queues(), workers->active_workers()); ::breakpoint()
; } } while (0)
720 num_queues(), workers->active_workers())do { if (!(workers->active_workers() >= num_queues())) {
(*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 720, "assert(" "workers->active_workers() >= num_queues()"
") failed", "Ergonomically chosen workers(%u) should be less than or equal to active workers(%u)"
, num_queues(), workers->active_workers()); ::breakpoint()
; } } while (0);
721 workers->run_task(&proxy_task, num_queues());
722 } else {
723 for (unsigned i = 0; i < _max_num_queues; ++i) {
724 proxy_task.work(i);
725 }
726 }
727}
728
729void ReferenceProcessor::process_soft_weak_final_refs(RefProcProxyTask& proxy_task,
730 ReferenceProcessorPhaseTimes& phase_times) {
731
732 size_t const num_soft_refs = phase_times.ref_discovered(REF_SOFT);
733 size_t const num_weak_refs = phase_times.ref_discovered(REF_WEAK);
734 size_t const num_final_refs = phase_times.ref_discovered(REF_FINAL);
735 size_t const num_total_refs = num_soft_refs + num_weak_refs + num_final_refs;
736
737 if (num_total_refs == 0) {
738 log_debug(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Debug))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Debug>("Skipped SoftWeakFinalRefsPhase of Reference Processing: no references");
739 return;
740 }
741
742 RefProcMTDegreeAdjuster a(this, SoftWeakFinalRefsPhase, num_total_refs);
743
744 if (processing_is_mt()) {
745 RefProcBalanceQueuesTimeTracker tt(SoftWeakFinalRefsPhase, &phase_times);
746 maybe_balance_queues(_discoveredSoftRefs);
747 maybe_balance_queues(_discoveredWeakRefs);
748 maybe_balance_queues(_discoveredFinalRefs);
749 }
750
751 RefProcPhaseTimeTracker tt(SoftWeakFinalRefsPhase, &phase_times);
752
753 log_reflist("SoftWeakFinalRefsPhase Soft before", _discoveredSoftRefs, _max_num_queues);
754 log_reflist("SoftWeakFinalRefsPhase Weak before", _discoveredWeakRefs, _max_num_queues);
755 log_reflist("SoftWeakFinalRefsPhase Final before", _discoveredFinalRefs, _max_num_queues);
756
757 RefProcSoftWeakFinalPhaseTask phase_task(*this, &phase_times);
758 run_task(phase_task, proxy_task, false);
759
760 verify_total_count_zero(_discoveredSoftRefs, "SoftReference");
761 verify_total_count_zero(_discoveredWeakRefs, "WeakReference");
762 log_reflist("SoftWeakFinalRefsPhase Final after", _discoveredFinalRefs, _max_num_queues);
763}
764
765void ReferenceProcessor::process_final_keep_alive(RefProcProxyTask& proxy_task,
766 ReferenceProcessorPhaseTimes& phase_times) {
767
768 size_t const num_final_refs = phase_times.ref_discovered(REF_FINAL);
769
770 if (num_final_refs == 0) {
771 log_debug(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Debug))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Debug>("Skipped KeepAliveFinalRefsPhase of Reference Processing: no references");
772 return;
773 }
774
775 RefProcMTDegreeAdjuster a(this, KeepAliveFinalRefsPhase, num_final_refs);
776
777 if (processing_is_mt()) {
778 RefProcBalanceQueuesTimeTracker tt(KeepAliveFinalRefsPhase, &phase_times);
779 maybe_balance_queues(_discoveredFinalRefs);
780 }
781
782 // Traverse referents of final references and keep them and followers alive.
783 RefProcPhaseTimeTracker tt(KeepAliveFinalRefsPhase, &phase_times);
784 RefProcKeepAliveFinalPhaseTask phase_task(*this, &phase_times);
785 run_task(phase_task, proxy_task, true);
786
787 verify_total_count_zero(_discoveredFinalRefs, "FinalReference");
788}
789
790void ReferenceProcessor::process_phantom_refs(RefProcProxyTask& proxy_task,
791 ReferenceProcessorPhaseTimes& phase_times) {
792
793 size_t const num_phantom_refs = phase_times.ref_discovered(REF_PHANTOM);
794
795 if (num_phantom_refs == 0) {
796 log_debug(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Debug))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Debug>("Skipped PhantomRefsPhase of Reference Processing: no references");
797 return;
798 }
799
800 RefProcMTDegreeAdjuster a(this, PhantomRefsPhase, num_phantom_refs);
801
802 if (processing_is_mt()) {
803 RefProcBalanceQueuesTimeTracker tt(PhantomRefsPhase, &phase_times);
804 maybe_balance_queues(_discoveredPhantomRefs);
805 }
806
807 // Walk phantom references appropriately.
808 RefProcPhaseTimeTracker tt(PhantomRefsPhase, &phase_times);
809
810 log_reflist("PhantomRefsPhase Phantom before", _discoveredPhantomRefs, _max_num_queues);
811
812 RefProcPhantomPhaseTask phase_task(*this, &phase_times);
813 run_task(phase_task, proxy_task, false);
814
815 verify_total_count_zero(_discoveredPhantomRefs, "PhantomReference");
816}
817
818inline DiscoveredList* ReferenceProcessor::get_discovered_list(ReferenceType rt) {
819 uint id = 0;
820 // Determine the queue index to use for this object.
821 if (_discovery_is_mt) {
822 // During a multi-threaded discovery phase,
823 // each thread saves to its "own" list.
824 id = WorkerThread::worker_id();
825 } else {
826 // single-threaded discovery, we save in round-robin
827 // fashion to each of the lists.
828 if (processing_is_mt()) {
829 id = next_id();
830 }
831 }
832 assert(id < _max_num_queues, "Id is out of bounds id %u and max id %u)", id, _max_num_queues)do { if (!(id < _max_num_queues)) { (*g_assert_poison) = 'X'
;; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 832, "assert(" "id < _max_num_queues" ") failed", "Id is out of bounds id %u and max id %u)"
, id, _max_num_queues); ::breakpoint(); } } while (0);
833
834 // Get the discovered queue to which we will add
835 DiscoveredList* list = NULL__null;
836 switch (rt) {
837 case REF_OTHER:
838 // Unknown reference type, no special treatment
839 break;
840 case REF_SOFT:
841 list = &_discoveredSoftRefs[id];
842 break;
843 case REF_WEAK:
844 list = &_discoveredWeakRefs[id];
845 break;
846 case REF_FINAL:
847 list = &_discoveredFinalRefs[id];
848 break;
849 case REF_PHANTOM:
850 list = &_discoveredPhantomRefs[id];
851 break;
852 case REF_NONE:
853 // we should not reach here if we are an InstanceRefKlass
854 default:
855 ShouldNotReachHere()do { (*g_assert_poison) = 'X';; report_should_not_reach_here(
"/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 855); ::breakpoint(); } while (0);
856 }
857 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Thread %d gets list " INTPTR_FORMAT"0x%016" "l" "x", id, p2i(list));
858 return list;
859}
860
861inline bool ReferenceProcessor::set_discovered_link(HeapWord* discovered_addr, oop next_discovered) {
862 return discovery_is_mt() ? set_discovered_link_mt(discovered_addr, next_discovered)
863 : set_discovered_link_st(discovered_addr, next_discovered);
864}
865
866inline void ReferenceProcessor::add_to_discovered_list(DiscoveredList& refs_list,
867 oop obj,
868 HeapWord* discovered_addr) {
869 oop current_head = refs_list.head();
870 // Prepare value to put into the discovered field. The last ref must have its
871 // discovered field pointing to itself.
872 oop next_discovered = (current_head != NULL__null) ? current_head : obj;
873
874 bool added = set_discovered_link(discovered_addr, next_discovered);
875 if (added) {
876 // We can always add the object without synchronization: every thread has its
877 // own list head.
878 refs_list.add_as_head(obj);
879 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Discovered reference (%s) (" INTPTR_FORMAT"0x%016" "l" "x" ": %s)",
880 discovery_is_mt() ? "mt" : "st", p2i(obj), obj->klass()->internal_name());
881 } else {
882 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Already discovered reference (mt) (" INTPTR_FORMAT"0x%016" "l" "x" ": %s)",
883 p2i(obj), obj->klass()->internal_name());
884 }
885}
886
887inline bool ReferenceProcessor::set_discovered_link_st(HeapWord* discovered_addr,
888 oop next_discovered) {
889 assert(!discovery_is_mt(), "must be")do { if (!(!discovery_is_mt())) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 889, "assert(" "!discovery_is_mt()" ") failed", "must be");
::breakpoint(); } } while (0);
890
891 if (discovery_is_stw()) {
892 // Do a raw store here: the field will be visited later when processing
893 // the discovered references.
894 RawAccess<>::oop_store(discovered_addr, next_discovered);
895 } else {
896 HeapAccess<AS_NO_KEEPALIVE>::oop_store(discovered_addr, next_discovered);
897 }
898 // Always successful.
899 return true;
900}
901
902inline bool ReferenceProcessor::set_discovered_link_mt(HeapWord* discovered_addr,
903 oop next_discovered) {
904 assert(discovery_is_mt(), "must be")do { if (!(discovery_is_mt())) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 904, "assert(" "discovery_is_mt()" ") failed", "must be"); ::
breakpoint(); } } while (0);
905
906 // We must make sure this object is only enqueued once. Try to CAS into the discovered_addr.
907 oop retest;
908 if (discovery_is_stw()) {
909 // Try a raw store here, still making sure that we enqueue only once: the field
910 // will be visited later when processing the discovered references.
911 retest = RawAccess<>::oop_atomic_cmpxchg(discovered_addr, oop(NULL__null), next_discovered);
912 } else {
913 retest = HeapAccess<AS_NO_KEEPALIVE>::oop_atomic_cmpxchg(discovered_addr, oop(NULL__null), next_discovered);
914 }
915 return retest == NULL__null;
916}
917
918#ifndef PRODUCT
919// Concurrent discovery might allow us to observe j.l.References with NULL
920// referents, being those cleared concurrently by mutators during (or after) discovery.
921void ReferenceProcessor::verify_referent(oop obj) {
922 bool concurrent = discovery_is_concurrent();
923 oop referent = java_lang_ref_Reference::unknown_referent_no_keepalive(obj);
924 assert(concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc::is_oop(referent),do { if (!(concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc
::is_oop(referent))) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 927, "assert(" "concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc::is_oop(referent)"
") failed", "Bad referent " "0x%016" "l" "x" " found in Reference "
"0x%016" "l" "x" " during %sconcurrent discovery ", p2i(referent
), p2i(obj), concurrent ? "" : "non-"); ::breakpoint(); } } while
(0)
925 "Bad referent " INTPTR_FORMAT " found in Reference "do { if (!(concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc
::is_oop(referent))) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 927, "assert(" "concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc::is_oop(referent)"
") failed", "Bad referent " "0x%016" "l" "x" " found in Reference "
"0x%016" "l" "x" " during %sconcurrent discovery ", p2i(referent
), p2i(obj), concurrent ? "" : "non-"); ::breakpoint(); } } while
(0)
926 INTPTR_FORMAT " during %sconcurrent discovery ",do { if (!(concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc
::is_oop(referent))) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 927, "assert(" "concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc::is_oop(referent)"
") failed", "Bad referent " "0x%016" "l" "x" " found in Reference "
"0x%016" "l" "x" " during %sconcurrent discovery ", p2i(referent
), p2i(obj), concurrent ? "" : "non-"); ::breakpoint(); } } while
(0)
927 p2i(referent), p2i(obj), concurrent ? "" : "non-")do { if (!(concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc
::is_oop(referent))) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 927, "assert(" "concurrent ? oopDesc::is_oop_or_null(referent) : oopDesc::is_oop(referent)"
") failed", "Bad referent " "0x%016" "l" "x" " found in Reference "
"0x%016" "l" "x" " during %sconcurrent discovery ", p2i(referent
), p2i(obj), concurrent ? "" : "non-"); ::breakpoint(); } } while
(0);
928}
929#endif
930
931bool ReferenceProcessor::is_subject_to_discovery(oop const obj) const {
932 return _is_subject_to_discovery->do_object_b(obj);
933}
934
935// We mention two of several possible choices here:
936// #0: if the reference object is not in the "originating generation"
937// (or part of the heap being collected, indicated by our "span")
938// we don't treat it specially (i.e. we scan it as we would
939// a normal oop, treating its references as strong references).
940// This means that references can't be discovered unless their
941// referent is also in the same span. This is the simplest,
942// most "local" and most conservative approach, albeit one
943// that may cause weak references to be enqueued least promptly.
944// We call this choice the "ReferenceBasedDiscovery" policy.
945// #1: the reference object may be in any generation (span), but if
946// the referent is in the generation (span) being currently collected
947// then we can discover the reference object, provided
948// the object has not already been discovered by
949// a different concurrently running discoverer (as may be the
950// case, for instance, if the reference object is in G1 old gen and
951// the referent in G1 young gen), and provided the processing
952// of this reference object by the current collector will
953// appear atomically to every other discoverer in the system.
954// (Thus, for instance, a concurrent discoverer may not
955// discover references in other generations even if the
956// referent is in its own generation). This policy may,
957// in certain cases, enqueue references somewhat sooner than
958// might Policy #0 above, but at marginally increased cost
959// and complexity in processing these references.
960// We call this choice the "ReferentBasedDiscovery" policy.
961bool ReferenceProcessor::discover_reference(oop obj, ReferenceType rt) {
962 // Make sure we are discovering refs (rather than processing discovered refs).
963 if (!_discovering_refs || !RegisterReferences) {
964 return false;
965 }
966
967 if ((rt == REF_FINAL) && (java_lang_ref_Reference::next(obj) != NULL__null)) {
968 // Don't rediscover non-active FinalReferences.
969 return false;
970 }
971
972 if (RefDiscoveryPolicy == ReferenceBasedDiscovery &&
973 !is_subject_to_discovery(obj)) {
974 // Reference is not in the originating generation;
975 // don't treat it specially (i.e. we want to scan it as a normal
976 // object with strong references).
977 return false;
978 }
979
980 // We only discover references whose referents are not (yet)
981 // known to be strongly reachable.
982 if (is_alive_non_header() != NULL__null) {
983 verify_referent(obj);
984 oop referent = java_lang_ref_Reference::unknown_referent_no_keepalive(obj);
985 if (is_alive_non_header()->do_object_b(referent)) {
986 return false; // referent is reachable
987 }
988 }
989 if (rt == REF_SOFT) {
990 // For soft refs we can decide now if these are not
991 // current candidates for clearing, in which case we
992 // can mark through them now, rather than delaying that
993 // to the reference-processing phase. Since all current
994 // time-stamp policies advance the soft-ref clock only
995 // at a full collection cycle, this is always currently
996 // accurate.
997 if (!_current_soft_ref_policy->should_clear_reference(obj, _soft_ref_timestamp_clock)) {
998 return false;
999 }
1000 }
1001
1002 ResourceMark rm; // Needed for tracing.
1003
1004 HeapWord* const discovered_addr = java_lang_ref_Reference::discovered_addr_raw(obj);
1005 const oop discovered = java_lang_ref_Reference::discovered(obj);
1006 assert(oopDesc::is_oop_or_null(discovered), "Expected an oop or NULL for discovered field at " PTR_FORMAT, p2i(discovered))do { if (!(oopDesc::is_oop_or_null(discovered))) { (*g_assert_poison
) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1006, "assert(" "oopDesc::is_oop_or_null(discovered)" ") failed"
, "Expected an oop or NULL for discovered field at " "0x%016"
"l" "x", p2i(discovered)); ::breakpoint(); } } while (0);
1007 if (discovered != NULL__null) {
1008 // The reference has already been discovered...
1009 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>("Already discovered reference (" INTPTR_FORMAT"0x%016" "l" "x" ": %s)",
1010 p2i(obj), obj->klass()->internal_name());
1011 if (RefDiscoveryPolicy == ReferentBasedDiscovery) {
1012 // assumes that an object is not processed twice;
1013 // if it's been already discovered it must be on another
1014 // generation's discovered list; so we won't discover it.
1015 return false;
1016 } else {
1017 assert(RefDiscoveryPolicy == ReferenceBasedDiscovery,do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery)) { (
*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1018, "assert(" "RefDiscoveryPolicy == ReferenceBasedDiscovery"
") failed", "Unrecognized policy"); ::breakpoint(); } } while
(0)
1018 "Unrecognized policy")do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery)) { (
*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1018, "assert(" "RefDiscoveryPolicy == ReferenceBasedDiscovery"
") failed", "Unrecognized policy"); ::breakpoint(); } } while
(0);
1019 // Check assumption that an object is not potentially
1020 // discovered twice except by concurrent collectors that potentially
1021 // trace the same Reference object twice.
1022 assert(UseG1GC, "Only possible with a concurrent marking collector")do { if (!(UseG1GC)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1022, "assert(" "UseG1GC" ") failed", "Only possible with a concurrent marking collector"
); ::breakpoint(); } } while (0);
1023 return true;
1024 }
1025 }
1026
1027 if (RefDiscoveryPolicy == ReferentBasedDiscovery) {
1028 verify_referent(obj);
1029 // Discover if and only if EITHER:
1030 // .. reference is in our span, OR
1031 // .. we are a stw discoverer and referent is in our span
1032 if (is_subject_to_discovery(obj) ||
1033 (discovery_is_stw() &&
1034 is_subject_to_discovery(java_lang_ref_Reference::unknown_referent_no_keepalive(obj)))) {
1035 } else {
1036 return false;
1037 }
1038 } else {
1039 assert(RefDiscoveryPolicy == ReferenceBasedDiscovery &&do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery &&
is_subject_to_discovery(obj))) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1040, "assert(" "RefDiscoveryPolicy == ReferenceBasedDiscovery && is_subject_to_discovery(obj)"
") failed", "code inconsistency"); ::breakpoint(); } } while
(0)
1040 is_subject_to_discovery(obj), "code inconsistency")do { if (!(RefDiscoveryPolicy == ReferenceBasedDiscovery &&
is_subject_to_discovery(obj))) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1040, "assert(" "RefDiscoveryPolicy == ReferenceBasedDiscovery && is_subject_to_discovery(obj)"
") failed", "code inconsistency"); ::breakpoint(); } } while
(0);
1041 }
1042
1043 // Get the right type of discovered queue head.
1044 DiscoveredList* list = get_discovered_list(rt);
1045 if (list == NULL__null) {
1046 return false; // nothing special needs to be done
1047 }
1048
1049 add_to_discovered_list(*list, obj, discovered_addr);
1050
1051 assert(oopDesc::is_oop(obj), "Discovered a bad reference")do { if (!(oopDesc::is_oop(obj))) { (*g_assert_poison) = 'X';
; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1051, "assert(" "oopDesc::is_oop(obj)" ") failed", "Discovered a bad reference"
); ::breakpoint(); } } while (0);
1052 verify_referent(obj);
1053 return true;
1054}
1055
1056void ReferenceProcessor::preclean_discovered_references(BoolObjectClosure* is_alive,
1057 EnqueueDiscoveredFieldClosure* enqueue,
1058 YieldClosure* yield,
1059 GCTimer* gc_timer) {
1060 // These lists can be handled here in any order and, indeed, concurrently.
1061
1062 // Soft references
1063 {
1064 GCTraceTime(Debug, gc, ref)GCTraceTimeWrapper<LogLevel::Debug, (LogTag::_gc), (LogTag
::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG)> tm("Preclean SoftReferences", gc_timer);
1065 log_reflist("SoftRef before: ", _discoveredSoftRefs, _max_num_queues);
1066 for (uint i = 0; i < _max_num_queues; i++) {
1067 if (yield->should_return()) {
1068 return;
1069 }
1070 if (preclean_discovered_reflist(_discoveredSoftRefs[i], is_alive,
1071 enqueue, yield)) {
1072 log_reflist("SoftRef abort: ", _discoveredSoftRefs, _max_num_queues);
1073 return;
1074 }
1075 }
1076 log_reflist("SoftRef after: ", _discoveredSoftRefs, _max_num_queues);
1077 }
1078
1079 // Weak references
1080 {
1081 GCTraceTime(Debug, gc, ref)GCTraceTimeWrapper<LogLevel::Debug, (LogTag::_gc), (LogTag
::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG)> tm("Preclean WeakReferences", gc_timer);
1082 log_reflist("WeakRef before: ", _discoveredWeakRefs, _max_num_queues);
1083 for (uint i = 0; i < _max_num_queues; i++) {
1084 if (yield->should_return()) {
1085 return;
1086 }
1087 if (preclean_discovered_reflist(_discoveredWeakRefs[i], is_alive,
1088 enqueue, yield)) {
1089 log_reflist("WeakRef abort: ", _discoveredWeakRefs, _max_num_queues);
1090 return;
1091 }
1092 }
1093 log_reflist("WeakRef after: ", _discoveredWeakRefs, _max_num_queues);
1094 }
1095
1096 // Final references
1097 {
1098 GCTraceTime(Debug, gc, ref)GCTraceTimeWrapper<LogLevel::Debug, (LogTag::_gc), (LogTag
::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG)> tm("Preclean FinalReferences", gc_timer);
1099 log_reflist("FinalRef before: ", _discoveredFinalRefs, _max_num_queues);
1100 for (uint i = 0; i < _max_num_queues; i++) {
1101 if (yield->should_return()) {
1102 return;
1103 }
1104 if (preclean_discovered_reflist(_discoveredFinalRefs[i], is_alive,
1105 enqueue, yield)) {
1106 log_reflist("FinalRef abort: ", _discoveredFinalRefs, _max_num_queues);
1107 return;
1108 }
1109 }
1110 log_reflist("FinalRef after: ", _discoveredFinalRefs, _max_num_queues);
1111 }
1112
1113 // Phantom references
1114 {
1115 GCTraceTime(Debug, gc, ref)GCTraceTimeWrapper<LogLevel::Debug, (LogTag::_gc), (LogTag
::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG)> tm("Preclean PhantomReferences", gc_timer);
1116 log_reflist("PhantomRef before: ", _discoveredPhantomRefs, _max_num_queues);
1117 for (uint i = 0; i < _max_num_queues; i++) {
1118 if (yield->should_return()) {
1119 return;
1120 }
1121 if (preclean_discovered_reflist(_discoveredPhantomRefs[i], is_alive,
1122 enqueue, yield)) {
1123 log_reflist("PhantomRef abort: ", _discoveredPhantomRefs, _max_num_queues);
1124 return;
1125 }
1126 }
1127 log_reflist("PhantomRef after: ", _discoveredPhantomRefs, _max_num_queues);
1128 }
1129}
1130
1131bool ReferenceProcessor::preclean_discovered_reflist(DiscoveredList& refs_list,
1132 BoolObjectClosure* is_alive,
1133 EnqueueDiscoveredFieldClosure* enqueue,
1134 YieldClosure* yield) {
1135 DiscoveredListIterator iter(refs_list, nullptr /* keep_alive */, is_alive, enqueue);
1136 while (iter.has_next()) {
1137 if (yield->should_return_fine_grain()) {
1138 return true;
1139 }
1140 iter.load_ptrs(DEBUG_ONLY(true /* allow_null_referent */)true);
1141 if (iter.referent() == nullptr) {
1142 log_preclean_ref(iter, "cleared");
1143 iter.remove();
1144 iter.move_to_next();
1145 } else if (iter.is_referent_alive()) {
1146 log_preclean_ref(iter, "reachable");
1147 iter.remove();
1148 iter.move_to_next();
1149 } else {
1150 iter.next();
1151 }
1152 }
1153
1154 if (iter.processed() > 0) {
1155 log_develop_trace(gc, ref)(!(LogImpl<(LogTag::_gc), (LogTag::_ref), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG), (LogTag::__NO_TAG)
>::is_level(LogLevel::Trace))) ? (void)0 : LogImpl<(LogTag
::_gc), (LogTag::_ref), (LogTag::__NO_TAG), (LogTag::__NO_TAG
), (LogTag::__NO_TAG), (LogTag::__NO_TAG)>::write<LogLevel
::Trace>(" Dropped " SIZE_FORMAT"%" "l" "u" " Refs out of " SIZE_FORMAT"%" "l" "u" " Refs in discovered list " INTPTR_FORMAT"0x%016" "l" "x",
1156 iter.removed(), iter.processed(), p2i(&refs_list));
1157 }
1158 return false;
1159}
1160
1161const char* ReferenceProcessor::list_name(uint i) {
1162 assert(i <= _max_num_queues * number_of_subclasses_of_ref(),do { if (!(i <= _max_num_queues * number_of_subclasses_of_ref
())) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1163, "assert(" "i <= _max_num_queues * number_of_subclasses_of_ref()"
") failed", "Out of bounds index"); ::breakpoint(); } } while
(0)
1163 "Out of bounds index")do { if (!(i <= _max_num_queues * number_of_subclasses_of_ref
())) { (*g_assert_poison) = 'X';; report_vm_error("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1163, "assert(" "i <= _max_num_queues * number_of_subclasses_of_ref()"
") failed", "Out of bounds index"); ::breakpoint(); } } while
(0);
1164
1165 int j = i / _max_num_queues;
1166 switch (j) {
1167 case 0: return "SoftRef";
1168 case 1: return "WeakRef";
1169 case 2: return "FinalRef";
1170 case 3: return "PhantomRef";
1171 }
1172 ShouldNotReachHere()do { (*g_assert_poison) = 'X';; report_should_not_reach_here(
"/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1172); ::breakpoint(); } while (0);
1173 return NULL__null;
1174}
1175
1176uint RefProcMTDegreeAdjuster::ergo_proc_thread_count(size_t ref_count,
1177 uint max_threads,
1178 RefProcPhases phase) const {
1179 assert(0 < max_threads, "must allow at least one thread")do { if (!(0 < max_threads)) { (*g_assert_poison) = 'X';; report_vm_error
("/home/daniel/Projects/java/jdk/src/hotspot/share/gc/shared/referenceProcessor.cpp"
, 1179, "assert(" "0 < max_threads" ") failed", "must allow at least one thread"
); ::breakpoint(); } } while (0);
1180
1181 if (use_max_threads(phase) || (ReferencesPerThread == 0)) {
1182 return max_threads;
1183 }
1184
1185 size_t thread_count = 1 + (ref_count / ReferencesPerThread);
1186 return (uint)MIN3(thread_count,
1187 static_cast<size_t>(max_threads),
1188 (size_t)os::active_processor_count());
1189}
1190
1191bool RefProcMTDegreeAdjuster::use_max_threads(RefProcPhases phase) const {
1192 // Even a small number of references in this phase could produce large amounts of work.
1193 return phase == ReferenceProcessor::KeepAliveFinalRefsPhase;
1194}
1195
1196RefProcMTDegreeAdjuster::RefProcMTDegreeAdjuster(ReferenceProcessor* rp,
1197 RefProcPhases phase,
1198 size_t ref_count):
1199 _rp(rp),
1200 _saved_num_queues(_rp->num_queues()) {
1201 uint workers = ergo_proc_thread_count(ref_count, _rp->num_queues(), phase);
1202 _rp->set_active_mt_degree(workers);
1203}
1204
1205RefProcMTDegreeAdjuster::~RefProcMTDegreeAdjuster() {
1206 // Revert to previous status.
1207 _rp->set_active_mt_degree(_saved_num_queues);
1208}