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8189368: Add information on current bias holder for BiasedLockRevocation event

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Reviewed-by: mgronlun, dholmes, egahlin
This commit is contained in:
Robin Westberg 2017-10-30 16:37:53 +01:00 • committed by Erik Gahlin
parent 832d68597e
commit b36ba5ff60
2 changed files with 30 additions and 10 deletions
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39
src/hotspot/share/runtime/biasedLocking.cpp
View file

@ -145,7 +145,9 @@ static GrowableArray<MonitorInfo*>* get_or_compute_monitor_info(JavaThread* thre
return info; return info;
} }
static BiasedLocking::Condition revoke_bias(oop obj, bool allow_rebias, bool is_bulk, JavaThread* requesting_thread) { // After the call, *biased_locker will be set to obj->mark()->biased_locker() if biased_locker != NULL,
// AND it is a living thread. Otherwise it will not be updated, (i.e. the caller is responsible for initialization).
static BiasedLocking::Condition revoke_bias(oop obj, bool allow_rebias, bool is_bulk, JavaThread* requesting_thread, JavaThread** biased_locker) {
markOop mark = obj->mark(); markOop mark = obj->mark();
if (!mark->has_bias_pattern()) { if (!mark->has_bias_pattern()) {
if (log_is_enabled(Info, biasedlocking)) { if (log_is_enabled(Info, biasedlocking)) {
@ -298,6 +300,11 @@ static BiasedLocking::Condition revoke_bias(oop obj, bool allow_rebias, bool is_
} }
} }
// If requested, return information on which thread held the bias
if (biased_locker != NULL) {
*biased_locker = biased_thread;
}
return BiasedLocking::BIAS_REVOKED; return BiasedLocking::BIAS_REVOKED;
} }
@ -418,7 +425,7 @@ static BiasedLocking::Condition bulk_revoke_or_rebias_at_safepoint(oop o,
// At this point we're done. All we have to do is potentially // At this point we're done. All we have to do is potentially
// adjust the header of the given object to revoke its bias. // adjust the header of the given object to revoke its bias.
revoke_bias(o, attempt_rebias_of_object && klass->prototype_header()->has_bias_pattern(), true, requesting_thread); revoke_bias(o, attempt_rebias_of_object && klass->prototype_header()->has_bias_pattern(), true, requesting_thread, NULL);
} else { } else {
if (log_is_enabled(Info, biasedlocking)) { if (log_is_enabled(Info, biasedlocking)) {
ResourceMark rm; ResourceMark rm;
@ -440,14 +447,14 @@ static BiasedLocking::Condition bulk_revoke_or_rebias_at_safepoint(oop o,
oop owner = mon_info->owner(); oop owner = mon_info->owner();
markOop mark = owner->mark(); markOop mark = owner->mark();
if ((owner->klass() == k_o) && mark->has_bias_pattern()) { if ((owner->klass() == k_o) && mark->has_bias_pattern()) {
revoke_bias(owner, false, true, requesting_thread); revoke_bias(owner, false, true, requesting_thread, NULL);
} }
} }
} }
// Must force the bias of the passed object to be forcibly revoked // Must force the bias of the passed object to be forcibly revoked
// as well to ensure guarantees to callers // as well to ensure guarantees to callers
revoke_bias(o, false, true, requesting_thread); revoke_bias(o, false, true, requesting_thread, NULL);
} }
log_info(biasedlocking)("* Ending bulk revocation"); log_info(biasedlocking)("* Ending bulk revocation");
@ -486,19 +493,22 @@ protected:
GrowableArray<Handle>* _objs; GrowableArray<Handle>* _objs;
JavaThread* _requesting_thread; JavaThread* _requesting_thread;
BiasedLocking::Condition _status_code; BiasedLocking::Condition _status_code;
traceid _biased_locker_id;
public: public:
VM_RevokeBias(Handle* obj, JavaThread* requesting_thread) VM_RevokeBias(Handle* obj, JavaThread* requesting_thread)
: _obj(obj) : _obj(obj)
, _objs(NULL) , _objs(NULL)
, _requesting_thread(requesting_thread) , _requesting_thread(requesting_thread)
, _status_code(BiasedLocking::NOT_BIASED) {} , _status_code(BiasedLocking::NOT_BIASED)
, _biased_locker_id(0) {}
VM_RevokeBias(GrowableArray<Handle>* objs, JavaThread* requesting_thread) VM_RevokeBias(GrowableArray<Handle>* objs, JavaThread* requesting_thread)
: _obj(NULL) : _obj(NULL)
, _objs(objs) , _objs(objs)
, _requesting_thread(requesting_thread) , _requesting_thread(requesting_thread)
, _status_code(BiasedLocking::NOT_BIASED) {} , _status_code(BiasedLocking::NOT_BIASED)
, _biased_locker_id(0) {}
virtual VMOp_Type type() const { return VMOp_RevokeBias; } virtual VMOp_Type type() const { return VMOp_RevokeBias; }
@ -525,7 +535,11 @@ public:
virtual void doit() { virtual void doit() {
if (_obj != NULL) { if (_obj != NULL) {
log_info(biasedlocking)("Revoking bias with potentially per-thread safepoint:"); log_info(biasedlocking)("Revoking bias with potentially per-thread safepoint:");
_status_code = revoke_bias((*_obj)(), false, false, _requesting_thread); JavaThread* biased_locker = NULL;
_status_code = revoke_bias((*_obj)(), false, false, _requesting_thread, &biased_locker);
if (biased_locker != NULL) {
_biased_locker_id = THREAD_TRACE_ID(biased_locker);
}
clean_up_cached_monitor_info(); clean_up_cached_monitor_info();
return; return;
} else { } else {
@ -537,6 +551,10 @@ public:
BiasedLocking::Condition status_code() const { BiasedLocking::Condition status_code() const {
return _status_code; return _status_code;
} }
traceid biased_locker() const {
return _biased_locker_id;
}
}; };
@ -645,7 +663,7 @@ BiasedLocking::Condition BiasedLocking::revoke_and_rebias(Handle obj, bool attem
ResourceMark rm; ResourceMark rm;
log_info(biasedlocking)("Revoking bias by walking my own stack:"); log_info(biasedlocking)("Revoking bias by walking my own stack:");
EventBiasedLockSelfRevocation event; EventBiasedLockSelfRevocation event;
BiasedLocking::Condition cond = revoke_bias(obj(), false, false, (JavaThread*) THREAD); BiasedLocking::Condition cond = revoke_bias(obj(), false, false, (JavaThread*) THREAD, NULL);
((JavaThread*) THREAD)->set_cached_monitor_info(NULL); ((JavaThread*) THREAD)->set_cached_monitor_info(NULL);
assert(cond == BIAS_REVOKED, "why not?"); assert(cond == BIAS_REVOKED, "why not?");
if (event.should_commit()) { if (event.should_commit()) {
@ -661,6 +679,7 @@ BiasedLocking::Condition BiasedLocking::revoke_and_rebias(Handle obj, bool attem
event.set_lockClass(k); event.set_lockClass(k);
// Subtract 1 to match the id of events committed inside the safepoint // Subtract 1 to match the id of events committed inside the safepoint
event.set_safepointId(SafepointSynchronize::safepoint_counter() - 1); event.set_safepointId(SafepointSynchronize::safepoint_counter() - 1);
event.set_previousOwner(revoke.biased_locker());
event.commit(); event.commit();
} }
return revoke.status_code(); return revoke.status_code();
@ -700,7 +719,7 @@ void BiasedLocking::revoke_at_safepoint(Handle h_obj) {
oop obj = h_obj(); oop obj = h_obj();
HeuristicsResult heuristics = update_heuristics(obj, false); HeuristicsResult heuristics = update_heuristics(obj, false);
if (heuristics == HR_SINGLE_REVOKE) { if (heuristics == HR_SINGLE_REVOKE) {
revoke_bias(obj, false, false, NULL); revoke_bias(obj, false, false, NULL, NULL);
} else if ((heuristics == HR_BULK_REBIAS) || } else if ((heuristics == HR_BULK_REBIAS) ||
(heuristics == HR_BULK_REVOKE)) { (heuristics == HR_BULK_REVOKE)) {
bulk_revoke_or_rebias_at_safepoint(obj, (heuristics == HR_BULK_REBIAS), false, NULL); bulk_revoke_or_rebias_at_safepoint(obj, (heuristics == HR_BULK_REBIAS), false, NULL);
@ -716,7 +735,7 @@ void BiasedLocking::revoke_at_safepoint(GrowableArray<Handle>* objs) {
oop obj = (objs->at(i))(); oop obj = (objs->at(i))();
HeuristicsResult heuristics = update_heuristics(obj, false); HeuristicsResult heuristics = update_heuristics(obj, false);
if (heuristics == HR_SINGLE_REVOKE) { if (heuristics == HR_SINGLE_REVOKE) {
revoke_bias(obj, false, false, NULL); revoke_bias(obj, false, false, NULL, NULL);
} else if ((heuristics == HR_BULK_REBIAS) || } else if ((heuristics == HR_BULK_REBIAS) ||
(heuristics == HR_BULK_REVOKE)) { (heuristics == HR_BULK_REVOKE)) {
bulk_revoke_or_rebias_at_safepoint(obj, (heuristics == HR_BULK_REBIAS), false, NULL); bulk_revoke_or_rebias_at_safepoint(obj, (heuristics == HR_BULK_REBIAS), false, NULL);

1
src/hotspot/share/trace/traceevents.xml
View file

@ -108,6 +108,7 @@ Declares a structure type that can be used in other events.
description="Revoked bias of object" has_thread="true" has_stacktrace="true" is_instant="false"> description="Revoked bias of object" has_thread="true" has_stacktrace="true" is_instant="false">
<value type="CLASS" field="lockClass" label="Lock Class" description="Class of object whose biased lock was revoked"/> <value type="CLASS" field="lockClass" label="Lock Class" description="Class of object whose biased lock was revoked"/>
<value type="INTEGER" field="safepointId" label="Safepoint Identifier" relation="SafepointId"/> <value type="INTEGER" field="safepointId" label="Safepoint Identifier" relation="SafepointId"/>
<value type="THREAD" field="previousOwner" label="Previous Owner" description="Thread owning the bias before revocation"/>
</event> </event>
<event id="BiasedLockSelfRevocation" path="java/biased_lock_self_revocation" label="Biased Lock Self Revocation" <event id="BiasedLockSelfRevocation" path="java/biased_lock_self_revocation" label="Biased Lock Self Revocation"