Mercurial > hg > truffle
changeset 1520:bb843ebc7c55
6919638: CMS: ExplicitGCInvokesConcurrent misinteracts with gc locker
Summary: GC-locker induced concurrent full gc should be asynchronous; policy now controlled by a separate flag, which defaults to false.
Reviewed-by: jmasa
author | ysr |
---|---|
date | Mon, 03 May 2010 20:19:05 -0700 |
parents | 7145628c2fa2 |
children | a8127dc669ba |
files | src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp src/share/vm/memory/genCollectedHeap.cpp src/share/vm/runtime/globals.hpp |
diffstat | 5 files changed, 14 insertions(+), 9 deletions(-) [+] |
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--- a/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Mon May 03 17:23:58 2010 -0400 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.cpp Mon May 03 20:19:05 2010 -0700 @@ -1424,10 +1424,9 @@ bool CMSCollector::shouldConcurrentCollect() { if (_full_gc_requested) { - assert(ExplicitGCInvokesConcurrent, "Unexpected state"); if (Verbose && PrintGCDetails) { gclog_or_tty->print_cr("CMSCollector: collect because of explicit " - " gc request"); + " gc request (or gc_locker)"); } return true; }
--- a/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp Mon May 03 17:23:58 2010 -0400 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.cpp Mon May 03 20:19:05 2010 -0700 @@ -163,6 +163,7 @@ // GenCollectedHeap heap. void VM_GenCollectFullConcurrent::doit() { assert(Thread::current()->is_VM_thread(), "Should be VM thread"); + assert(GCLockerInvokesConcurrent || ExplicitGCInvokesConcurrent, "Unexpected"); GenCollectedHeap* gch = GenCollectedHeap::heap(); if (_gc_count_before == gch->total_collections()) { @@ -190,7 +191,7 @@ CMSCollector::disable_icms(); // In case CMS thread was in icms_wait(), wake it up. CMSCollector::start_icms(); - // Nudge the CMS thread to start a concurrent collection + // Nudge the CMS thread to start a concurrent collection. CMSCollector::request_full_gc(_full_gc_count_before); } else { FullGCCount_lock->notify_all(); // Inform the Java thread its work is done @@ -231,7 +232,9 @@ // e.g. at the rate of 1 full gc per ms, this could // overflow in about 1000 years. GenCollectedHeap* gch = GenCollectedHeap::heap(); - if (gch->total_full_collections_completed() <= _full_gc_count_before) { + if (_gc_cause != GCCause::_gc_locker && + gch->total_full_collections_completed() <= _full_gc_count_before) { + assert(ExplicitGCInvokesConcurrent, "Error"); // Now, wait for witnessing concurrent gc cycle to complete, // but do so in native mode, because we want to lock the // FullGCEvent_lock, which may be needed by the VM thread
--- a/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp Mon May 03 17:23:58 2010 -0400 +++ b/src/share/vm/gc_implementation/concurrentMarkSweep/vmCMSOperations.hpp Mon May 03 20:19:05 2010 -0700 @@ -126,8 +126,7 @@ GCCause::Cause gc_cause) : VM_GC_Operation(gc_count_before, full_gc_count_before, true /* full */) { _gc_cause = gc_cause; - assert(FullGCCount_lock != NULL && UseConcMarkSweepGC && - ExplicitGCInvokesConcurrent, "Otherwise shouldn't be here"); + assert(FullGCCount_lock != NULL, "Error"); assert(UseAsyncConcMarkSweepGC, "Else will hang caller"); } ~VM_GenCollectFullConcurrent() {}
--- a/src/share/vm/memory/genCollectedHeap.cpp Mon May 03 17:23:58 2010 -0400 +++ b/src/share/vm/memory/genCollectedHeap.cpp Mon May 03 20:19:05 2010 -0700 @@ -410,9 +410,9 @@ } bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { - return (cause == GCCause::_java_lang_system_gc || - cause == GCCause::_gc_locker) && - UseConcMarkSweepGC && ExplicitGCInvokesConcurrent; + return UseConcMarkSweepGC && + ((cause == GCCause::_gc_locker && GCLockerInvokesConcurrent) || + (cause == GCCause::_java_lang_system_gc && ExplicitGCInvokesConcurrent)); } void GenCollectedHeap::do_collection(bool full,
--- a/src/share/vm/runtime/globals.hpp Mon May 03 17:23:58 2010 -0400 +++ b/src/share/vm/runtime/globals.hpp Mon May 03 20:19:05 2010 -0700 @@ -1303,6 +1303,10 @@ "also unloads classes during such a concurrent gc cycle " \ "(effective only when UseConcMarkSweepGC)") \ \ + product(bool, GCLockerInvokesConcurrent, false, \ + "The exit of a JNI CS necessitating a scavenge also" \ + " kicks off a bkgrd concurrent collection") \ + \ develop(bool, UseCMSAdaptiveFreeLists, true, \ "Use Adaptive Free Lists in the CMS generation") \ \