8256306: ObjectMonitor::_contentions field should not be 'jint'
Reviewed-by: dholmes, stuefe, dcubed
This commit is contained in:
parent
52d5d1b361
commit
f3ba2690c5
src
hotspot/share/runtime
jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime
@ -485,7 +485,7 @@ bool ObjectMonitor::enter(JavaThread* current) {
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// just exited the monitor.
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}
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if (event.should_commit()) {
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event.set_previousOwner((uintptr_t)_previous_owner_tid);
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event.set_previousOwner(_previous_owner_tid);
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event.commit();
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}
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OM_PERFDATA_OP(ContendedLockAttempts, inc());
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@ -545,7 +545,7 @@ bool ObjectMonitor::deflate_monitor() {
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// Java threads. The GC already broke the association with the object.
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set_owner_from(NULL, DEFLATER_MARKER);
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assert(contentions() >= 0, "must be non-negative: contentions=%d", contentions());
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_contentions = -max_jint;
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_contentions = INT_MIN; // minimum negative int
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} else {
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// Attempt async deflation protocol.
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@ -572,7 +572,7 @@ bool ObjectMonitor::deflate_monitor() {
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// Make a zero contentions field negative to force any contending threads
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// to retry. This is the second part of the async deflation dance.
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if (Atomic::cmpxchg(&_contentions, (jint)0, -max_jint) != 0) {
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if (Atomic::cmpxchg(&_contentions, 0, INT_MIN) != 0) {
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// Contentions was no longer 0 so we lost the race since the
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// ObjectMonitor is now busy. Restore owner to NULL if it is
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// still DEFLATER_MARKER:
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@ -2243,7 +2243,7 @@ void ObjectMonitor::print_debug_style_on(outputStream* st) const {
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st->print_cr(" [%d] = '\\0'", (int)sizeof(_pad_buf0) - 1);
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st->print_cr(" }");
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st->print_cr(" _owner = " INTPTR_FORMAT, p2i(owner_raw()));
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st->print_cr(" _previous_owner_tid = " JLONG_FORMAT, _previous_owner_tid);
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st->print_cr(" _previous_owner_tid = " INTPTR_FORMAT, _previous_owner_tid);
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st->print_cr(" _pad_buf1 = {");
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st->print_cr(" [0] = '\\0'");
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st->print_cr(" ...");
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@ -148,13 +148,13 @@ class ObjectMonitor : public CHeapObj<mtInternal> {
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// Used by async deflation as a marker in the _owner field:
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#define DEFLATER_MARKER reinterpret_cast<void*>(-1)
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void* volatile _owner; // pointer to owning thread OR BasicLock
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volatile jlong _previous_owner_tid; // thread id of the previous owner of the monitor
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volatile uintptr_t _previous_owner_tid; // thread id of the previous owner of the monitor
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// Separate _owner and _next_om on different cache lines since
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// both can have busy multi-threaded access. _previous_owner_tid is only
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// changed by ObjectMonitor::exit() so it is a good choice to share the
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// cache line with _owner.
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DEFINE_PAD_MINUS_SIZE(1, OM_CACHE_LINE_SIZE, sizeof(void* volatile) +
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sizeof(volatile jlong));
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sizeof(volatile uintptr_t));
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ObjectMonitor* _next_om; // Next ObjectMonitor* linkage
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volatile intx _recursions; // recursion count, 0 for first entry
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ObjectWaiter* volatile _EntryList; // Threads blocked on entry or reentry.
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@ -168,13 +168,13 @@ class ObjectMonitor : public CHeapObj<mtInternal> {
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volatile int _Spinner; // for exit->spinner handoff optimization
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volatile int _SpinDuration;
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jint _contentions; // Number of active contentions in enter(). It is used by is_busy()
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int _contentions; // Number of active contentions in enter(). It is used by is_busy()
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// along with other fields to determine if an ObjectMonitor can be
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// deflated. It is also used by the async deflation protocol. See
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// ObjectMonitor::deflate_monitor().
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protected:
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ObjectWaiter* volatile _WaitSet; // LL of threads wait()ing on the monitor
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volatile jint _waiters; // number of waiting threads
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volatile int _waiters; // number of waiting threads
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private:
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volatile int _WaitSetLock; // protects Wait Queue - simple spinlock
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@ -238,9 +238,10 @@ class ObjectMonitor : public CHeapObj<mtInternal> {
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bool is_busy() const {
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// TODO-FIXME: assert _owner == null implies _recursions = 0
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intptr_t ret_code = _waiters | intptr_t(_cxq) | intptr_t(_EntryList);
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if (contentions() > 0) {
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ret_code |= contentions();
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intptr_t ret_code = intptr_t(_waiters) | intptr_t(_cxq) | intptr_t(_EntryList);
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int cnts = contentions(); // read once
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if (cnts > 0) {
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ret_code |= intptr_t(cnts);
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}
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if (!owner_is_DEFLATER_MARKER()) {
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ret_code |= intptr_t(owner_raw());
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@ -281,10 +282,10 @@ class ObjectMonitor : public CHeapObj<mtInternal> {
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// _next_om field. Returns the prior value of the _next_om field.
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ObjectMonitor* try_set_next_om(ObjectMonitor* old_value, ObjectMonitor* new_value);
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jint waiters() const;
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int waiters() const;
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jint contentions() const;
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void add_to_contentions(jint value);
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int contentions() const;
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void add_to_contentions(int value);
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intx recursions() const { return _recursions; }
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// JVM/TI GetObjectMonitorUsage() needs this:
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@ -52,7 +52,7 @@ inline void ObjectMonitor::set_header(markWord hdr) {
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Atomic::store(&_header, hdr);
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}
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inline jint ObjectMonitor::waiters() const {
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inline int ObjectMonitor::waiters() const {
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return _waiters;
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}
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@ -79,12 +79,12 @@ inline bool ObjectMonitor::is_being_async_deflated() {
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}
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// Return number of threads contending for this monitor.
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inline jint ObjectMonitor::contentions() const {
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inline int ObjectMonitor::contentions() const {
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return Atomic::load(&_contentions);
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}
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// Add value to the contentions field.
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inline void ObjectMonitor::add_to_contentions(jint value) {
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inline void ObjectMonitor::add_to_contentions(int value) {
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Atomic::add(&_contentions, value);
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}
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@ -881,8 +881,8 @@ typedef HashtableEntry<InstanceKlass*, mtClass> KlassHashtableEntry;
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unchecked_nonstatic_field(ObjectMonitor, _owner, sizeof(void *)) /* NOTE: no type */ \
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volatile_nonstatic_field(ObjectMonitor, _next_om, ObjectMonitor*) \
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volatile_nonstatic_field(BasicLock, _displaced_header, markWord) \
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nonstatic_field(ObjectMonitor, _contentions, jint) \
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volatile_nonstatic_field(ObjectMonitor, _waiters, jint) \
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nonstatic_field(ObjectMonitor, _contentions, int) \
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volatile_nonstatic_field(ObjectMonitor, _waiters, int) \
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volatile_nonstatic_field(ObjectMonitor, _recursions, intx) \
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nonstatic_field(BasicObjectLock, _lock, BasicLock) \
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nonstatic_field(BasicObjectLock, _obj, oop) \
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@ -1,5 +1,5 @@
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/*
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* Copyright (c) 2001, 2020, Oracle and/or its affiliates. All rights reserved.
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* Copyright (c) 2001, 2021, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@ -52,9 +52,9 @@ public class ObjectMonitor extends VMObject {
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ownerFieldOffset = f.getOffset();
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f = type.getField("_next_om");
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nextOMFieldOffset = f.getOffset();
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contentionsField = type.getJIntField("_contentions");
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waitersField = type.getJIntField("_waiters");
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recursionsField = type.getCIntegerField("_recursions");
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contentionsField = new CIntField(type.getCIntegerField("_contentions"), 0);
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waitersField = new CIntField(type.getCIntegerField("_waiters"), 0);
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recursionsField = type.getCIntegerField("_recursions");
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}
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public ObjectMonitor(Address addr) {
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@ -83,7 +83,7 @@ public class ObjectMonitor extends VMObject {
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// FIXME
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// void set_owner(void* owner);
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public int waiters() { return waitersField.getValue(addr); }
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public int waiters() { return (int)waitersField.getValue(this); }
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public Address nextOM() { return addr.getAddressAt(nextOMFieldOffset); }
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// FIXME
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@ -100,7 +100,7 @@ public class ObjectMonitor extends VMObject {
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}
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public int contentions() {
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return contentionsField.getValue(addr);
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return (int)contentionsField.getValue(this);
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}
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// The following four either aren't expressed as typed fields in
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@ -111,8 +111,8 @@ public class ObjectMonitor extends VMObject {
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private static long objectFieldOffset;
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private static long ownerFieldOffset;
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private static long nextOMFieldOffset;
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private static JIntField contentionsField;
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private static JIntField waitersField;
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private static CIntField contentionsField;
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private static CIntField waitersField;
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private static CIntegerField recursionsField;
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// FIXME: expose platform-dependent stuff
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}
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