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8061205: MetadataOnStackMark only needs to walk code cache during class redefinition

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Only do full metadata walk during class redefinition and only walk handles during class unloading.

Reviewed-by: sspitsyn, stefank
This commit is contained in:
Coleen Phillimore 2015-03-13 12:40:39 -04:00
parent 984cf4c9b5
commit 7b384c6958
19 changed files with 147 additions and 248 deletions
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42
hotspot/src/share/vm/oops/instanceKlass.cpp
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@ -3492,9 +3492,11 @@ void InstanceKlass::set_init_state(ClassState state) {
#endif
// RedefineClasses() support for previous versions:
// Purge previous versions
// RedefineClasses() support for previous versions:
int InstanceKlass::_previous_version_count = 0;
// Purge previous versions before adding new previous versions of the class.
void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
if (ik->previous_versions() != NULL) {
// This klass has previous versions so see what we can cleanup
@ -3524,6 +3526,11 @@ void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
// are executing. Unlink this previous_version.
// The previous version InstanceKlass is on the ClassLoaderData deallocate list
// so will be deallocated during the next phase of class unloading.
RC_TRACE(0x00000200, ("purge: previous version " INTPTR_FORMAT " is dead",
pv_node));
// For debugging purposes.
pv_node->set_is_scratch_class();
pv_node->class_loader_data()->add_to_deallocate_list(pv_node);
pv_node = pv_node->previous_versions();
last->link_previous_versions(pv_node);
deleted_count++;
@ -3537,7 +3544,7 @@ void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
live_count++;
}
// At least one method is live in this previous version so clean its MethodData.
// At least one method is live in this previous version.
// Reset dead EMCP methods not to get breakpoints.
// All methods are deallocated when all of the methods for this class are no
// longer running.
@ -3561,12 +3568,6 @@ void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
("purge: %s(%s): prev method @%d in version @%d is alive",
method->name()->as_C_string(),
method->signature()->as_C_string(), j, version));
#ifdef ASSERT
if (method->method_data() != NULL) {
// Verify MethodData for running methods don't refer to old methods.
method->method_data()->verify_clean_weak_method_links();
}
#endif // ASSERT
}
}
}
@ -3579,18 +3580,6 @@ void InstanceKlass::purge_previous_versions(InstanceKlass* ik) {
("purge: previous version stats: live=%d, deleted=%d", live_count,
deleted_count));
}
#ifdef ASSERT
// Verify clean MethodData for this class's methods, e.g. they don't refer to
// old methods that are no longer running.
Array<Method*>* methods = ik->methods();
int num_methods = methods->length();
for (int index = 0; index < num_methods; ++index) {
if (methods->at(index)->method_data() != NULL) {
methods->at(index)->method_data()->verify_clean_weak_method_links();
}
}
#endif // ASSERT
}
void InstanceKlass::mark_newly_obsolete_methods(Array<Method*>* old_methods,
@ -3677,6 +3666,11 @@ void InstanceKlass::add_previous_version(instanceKlassHandle scratch_class,
ConstantPool* cp_ref = scratch_class->constants();
if (!cp_ref->on_stack()) {
RC_TRACE(0x00000400, ("add: scratch class not added; no methods are running"));
// For debugging purposes.
scratch_class->set_is_scratch_class();
scratch_class->class_loader_data()->add_to_deallocate_list(scratch_class());
// Update count for class unloading.
_previous_version_count--;
return;
}
@ -3688,8 +3682,8 @@ void InstanceKlass::add_previous_version(instanceKlassHandle scratch_class,
// if EMCP method (not obsolete) is on the stack, mark as EMCP so that
// we can add breakpoints for it.
// We set the method->on_stack bit during safepoints for class redefinition and
// class unloading and use this bit to set the is_running_emcp bit.
// We set the method->on_stack bit during safepoints for class redefinition
// and use this bit to set the is_running_emcp bit.
// After the safepoint, the on_stack bit is cleared and the running emcp
// method may exit. If so, we would set a breakpoint in a method that
// is never reached, but this won't be noticeable to the programmer.
@ -3708,6 +3702,8 @@ void InstanceKlass::add_previous_version(instanceKlassHandle scratch_class,
assert(scratch_class->previous_versions() == NULL, "shouldn't have a previous version");
scratch_class->link_previous_versions(previous_versions());
link_previous_versions(scratch_class());
// Update count for class unloading.
_previous_version_count++;
} // end add_previous_version()