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8181859: Monitor deflation is not checked in cleanup path

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Reviewed-by: sspitsyn, dcubed, shade, cvarming
This commit is contained in:
Robbin Ehn 2017-06-15 09:52:44 +02:00
parent 2a0bd0cd04
commit 0d3624a309
4 changed files with 25 additions and 1 deletions
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6
hotspot/src/share/vm/runtime/globals.hpp
View file

@ -1184,6 +1184,12 @@ public:
\
product(bool, MonitorInUseLists, true, "Track Monitors for Deflation") \
\
experimental(intx, MonitorUsedDeflationThreshold, 90, \
"Percentage of used monitors before triggering cleanup " \
"safepoint which deflates monitors (0 is off). " \
"The check is performed on GuaranteedSafepointInterval.") \
range(0, 100) \
\
experimental(intx, SyncFlags, 0, "(Unsafe, Unstable) " \
"Experimental Sync flags") \
\

2
hotspot/src/share/vm/runtime/safepoint.cpp
View file

@ -525,6 +525,8 @@ void SafepointSynchronize::end() {
}
bool SafepointSynchronize::is_cleanup_needed() {
// Need a safepoint if there are many monitors to deflate.
if (ObjectSynchronizer::is_cleanup_needed()) return true;
// Need a safepoint if some inline cache buffers is non-empty
if (!InlineCacheBuffer::is_empty()) return true;
return false;

15
hotspot/src/share/vm/runtime/synchronizer.cpp
View file

@ -962,6 +962,21 @@ static inline ObjectMonitor* next(ObjectMonitor* block) {
return block;
}
static bool monitors_used_above_threshold() {
if (gMonitorPopulation == 0) {
return false;
}
int monitors_used = gMonitorPopulation - gMonitorFreeCount;
int monitor_usage = (monitors_used * 100LL) / gMonitorPopulation;
return monitor_usage > MonitorUsedDeflationThreshold;
}
bool ObjectSynchronizer::is_cleanup_needed() {
if (MonitorUsedDeflationThreshold > 0) {
return monitors_used_above_threshold();
}
return false;
}
void ObjectSynchronizer::oops_do(OopClosure* f) {
if (MonitorInUseLists) {

3
hotspot/src/share/vm/runtime/synchronizer.hpp
View file

@ -1,5 +1,5 @@
/*
* Copyright (c) 1998, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -135,6 +135,7 @@ class ObjectSynchronizer : AllStatic {
static bool deflate_monitor(ObjectMonitor* mid, oop obj,
ObjectMonitor** freeHeadp,
ObjectMonitor** freeTailp);
static bool is_cleanup_needed();
static void oops_do(OopClosure* f);
// Process oops in thread local used monitors
static void thread_local_used_oops_do(Thread* thread, OopClosure* f);