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8038212: Method::is_valid_method() check has performance regression impact for stackwalking

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Only prune metaspace virtual spaces at safepoint so walking them is safe outside a safepoint.

Reviewed-by: mgerdin, mgronlun, hseigel, stefank
This commit is contained in:
Coleen Phillimore 2014-05-15 18:23:26 -04:00
parent cc3c656cf1
commit c336175c94
13 changed files with 84 additions and 72 deletions
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29
hotspot/src/share/vm/classfile/classLoaderData.cpp
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@ -549,6 +549,8 @@ ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
bool ClassLoaderDataGraph::_should_purge = false;
// Add a new class loader data node to the list. Assign the newly created
// ClassLoaderData into the java/lang/ClassLoader object as a hidden field
ClassLoaderData* ClassLoaderDataGraph::add(Handle loader, bool is_anonymous, TRAPS) {
@ -675,32 +677,6 @@ GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
return array;
}
// For profiling and hsfind() only. Otherwise, this is unsafe (and slow). This
// is done lock free to avoid lock inversion problems. It is safe because
// new ClassLoaderData are added to the end of the CLDG, and only removed at
// safepoint. The _unloading list can be deallocated concurrently with CMS so
// this doesn't look in metaspace for classes that have been unloaded.
bool ClassLoaderDataGraph::contains(const void* x) {
if (DumpSharedSpaces) {
// There are only two metaspaces to worry about.
ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
}
if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
return true;
}
for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
return true;
}
}
// Do not check unloading list because deallocation can be concurrent.
return false;
}
#ifndef PRODUCT
bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
@ -759,6 +735,7 @@ bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
}
void ClassLoaderDataGraph::purge() {
assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");
ClassLoaderData* list = _unloading;
_unloading = NULL;
ClassLoaderData* next = list;