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8232788: Move biased locking initalization

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Reviewed-by: pchilanomate, dholmes
This commit is contained in:
Coleen Phillimore 2019-10-24 08:52:33 -04:00
parent 31ab60e211
commit 9308d18580
3 changed files with 18 additions and 21 deletions
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20
src/hotspot/share/classfile/systemDictionary.cpp
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@ -2132,26 +2132,6 @@ void SystemDictionary::update_dictionary(unsigned int d_hash,
{
MutexLocker mu1(SystemDictionary_lock, THREAD);
// See whether biased locking is enabled and if so set it for this
// klass.
// Note that this must be done past the last potential blocking
// point / safepoint. We might enable biased locking lazily using a
// VM_Operation to iterate the SystemDictionary and installing the
// biasable mark word into each InstanceKlass's prototype header.
// To avoid race conditions where we accidentally miss enabling the
// optimization for one class in the process of being added to the
// dictionary, we must not safepoint after the test of
// BiasedLocking::enabled().
if (UseBiasedLocking && BiasedLocking::enabled()) {
// Set biased locking bit for all loaded classes; it will be
// cleared if revocation occurs too often for this type
// NOTE that we must only do this when the class is initally
// defined, not each time it is referenced from a new class loader
if (k->class_loader() == class_loader()) {
k->set_prototype_header(markWord::biased_locking_prototype());
}
}
// Make a new dictionary entry.
Dictionary* dictionary = loader_data->dictionary();
InstanceKlass* sd_check = find_class(d_hash, name, dictionary);

12
src/hotspot/share/oops/instanceKlass.cpp
View File

@ -69,6 +69,7 @@
#include "prims/jvmtiThreadState.hpp"
#include "prims/methodComparator.hpp"
#include "runtime/atomic.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/fieldDescriptor.inline.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/javaCalls.hpp"
@ -456,6 +457,12 @@ InstanceKlass::InstanceKlass(const ClassFileParser& parser, unsigned kind, Klass
if (Arguments::is_dumping_archive()) {
SystemDictionaryShared::init_dumptime_info(this);
}
// Set biased locking bit for all instances of this class; it will be
// cleared if revocation occurs too often for this type
if (UseBiasedLocking && BiasedLocking::enabled()) {
set_prototype_header(markWord::biased_locking_prototype());
}
}
void InstanceKlass::deallocate_methods(ClassLoaderData* loader_data,
@ -2408,6 +2415,11 @@ void InstanceKlass::restore_unshareable_info(ClassLoaderData* loader_data, Handl
// --> see ArrayKlass::complete_create_array_klass()
array_klasses()->restore_unshareable_info(ClassLoaderData::the_null_class_loader_data(), Handle(), CHECK);
}
// Initialize current biased locking state.
if (UseBiasedLocking && BiasedLocking::enabled()) {
set_prototype_header(markWord::biased_locking_prototype());
}
}
// returns true IFF is_in_error_state() has been changed as a result of this call.

7
test/hotspot/gtest/oops/test_markOop.cpp → test/hotspot/gtest/oops/test_markWord.cpp
View File

@ -27,6 +27,7 @@
#include "memory/universe.hpp"
#include "oops/oop.inline.hpp"
#include "runtime/atomic.hpp"
#include "runtime/biasedLocking.hpp"
#include "runtime/interfaceSupport.inline.hpp"
#include "runtime/orderAccess.hpp"
#include "runtime/os.hpp"
@ -84,10 +85,14 @@ TEST_VM(markWord, printing) {
ThreadInVMfromNative invm(THREAD);
ResourceMark rm(THREAD);
if (!UseBiasedLocking || !BiasedLocking::enabled()) {
// Can't test this with biased locking disabled.
return;
}
oop obj = SystemDictionary::Byte_klass()->allocate_instance(THREAD);
FlagSetting fs(WizardMode, true);
FlagSetting bf(UseBiasedLocking, true);
HandleMark hm(THREAD);
Handle h_obj(THREAD, obj);