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8213092: Add more runtime locks for concurrent class unloading

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Add locks for calling CLDG::purge concurrently as well and for calling SystemDictionary::do_unloading concurrently.

Reviewed-by: eosterlund, hseigel
This commit is contained in:
Coleen Phillimore 2018-11-16 10:54:04 -05:00
parent dce8ff4dba
commit 673c68d993
6 changed files with 36 additions and 43 deletions
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34
src/hotspot/share/classfile/systemDictionary.cpp
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@ -1807,18 +1807,26 @@ void SystemDictionary::add_to_hierarchy(InstanceKlass* k, TRAPS) {
bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
bool unloading_occurred;
bool is_concurrent = !SafepointSynchronize::is_at_safepoint();
{
GCTraceTime(Debug, gc, phases) t("ClassLoaderData", gc_timer);
assert_locked_or_safepoint(ClassLoaderDataGraph_lock); // caller locks.
// First, mark for unload all ClassLoaderData referencing a dead class loader.
unloading_occurred = ClassLoaderDataGraph::do_unloading();
if (unloading_occurred) {
MutexLockerEx ml2(is_concurrent ? Module_lock : NULL);
JFR_ONLY(Jfr::on_unloading_classes();)
MutexLockerEx ml1(is_concurrent ? SystemDictionary_lock : NULL);
ClassLoaderDataGraph::clean_module_and_package_info();
}
}
// TODO: just return if !unloading_occurred.
// Cleanup ResolvedMethodTable even if no unloading occurred.
{
GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
ResolvedMethodTable::trigger_cleanup();
}
if (unloading_occurred) {
{
GCTraceTime(Debug, gc, phases) t("SymbolTable", gc_timer);
@ -1827,23 +1835,21 @@ bool SystemDictionary::do_unloading(GCTimer* gc_timer) {
}
{
MutexLockerEx ml(is_concurrent ? SystemDictionary_lock : NULL);
GCTraceTime(Debug, gc, phases) t("Dictionary", gc_timer);
constraints()->purge_loader_constraints();
resolution_errors()->purge_resolution_errors();
}
}
{
GCTraceTime(Debug, gc, phases) t("ProtectionDomainCacheTable", gc_timer);
// Oops referenced by the protection domain cache table may get unreachable independently
// of the class loader (eg. cached protection domain oops). So we need to
// explicitly unlink them here.
_pd_cache_table->trigger_cleanup();
}
{
GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
ResolvedMethodTable::trigger_cleanup();
{
GCTraceTime(Debug, gc, phases) t("ResolvedMethodTable", gc_timer);
// Oops referenced by the protection domain cache table may get unreachable independently
// of the class loader (eg. cached protection domain oops). So we need to
// explicitly unlink them here.
// All protection domain oops are linked to the caller class, so if nothing
// unloads, this is not needed.
_pd_cache_table->trigger_cleanup();
}
}
return unloading_occurred;