8210889: Some service thread cleanups can be starved
Summary: Do all available work on each iteration.
Reviewed-by: pliden, tschatzl, coleenp
--- a/src/hotspot/share/runtime/serviceThread.cpp Wed Sep 19 16:07:03 2018 -0700
+++ b/src/hotspot/share/runtime/serviceThread.cpp Wed Sep 19 20:07:02 2018 -0400
@@ -86,7 +86,6 @@
bool has_jvmti_events = false;
bool has_gc_notification_event = false;
bool has_dcmd_notification_event = false;
- bool acs_notify = false;
bool stringtable_work = false;
bool symboltable_work = false;
bool resolved_method_table_work = false;
@@ -104,16 +103,20 @@
ThreadBlockInVM tbivm(jt);
MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
- while (!(sensors_changed = LowMemoryDetector::has_pending_requests()) &&
- !(has_jvmti_events = JvmtiDeferredEventQueue::has_events()) &&
- !(has_gc_notification_event = GCNotifier::has_event()) &&
- !(has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) &&
- !(stringtable_work = StringTable::has_work()) &&
- !(symboltable_work = SymbolTable::has_work()) &&
- !(resolved_method_table_work = ResolvedMethodTable::has_work()) &&
- !(protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work())) {
- // wait until one of the sensors has pending requests, or there is a
- // pending JVMTI event or JMX GC notification to post
+ // Process all available work on each (outer) iteration, rather than
+ // only the first recognized bit of work, to avoid frequently true early
+ // tests from potentially starving later work. Hence the use of
+ // arithmetic-or to combine results; we don't want short-circuiting.
+ while (((sensors_changed = LowMemoryDetector::has_pending_requests()) |
+ (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |
+ (has_gc_notification_event = GCNotifier::has_event()) |
+ (has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) |
+ (stringtable_work = StringTable::has_work()) |
+ (symboltable_work = SymbolTable::has_work()) |
+ (resolved_method_table_work = ResolvedMethodTable::has_work()) |
+ (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()))
+ == 0) {
+ // Wait until notified that there is some work to do.
Service_lock->wait(Mutex::_no_safepoint_check_flag);
}