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8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects

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Removed all write barriers during reference processing and added explicit write barriers when iterating through the discovered list.

Reviewed-by: pliden, jmasa, tschatzl
This commit is contained in:
Bengt Rutisson 2014-06-03 10:44:36 +02:00
parent 3e5805dc08
commit 426151a22e
7 changed files with 38 additions and 96 deletions
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23
hotspot/src/share/vm/memory/referenceProcessor.hpp
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@ -99,7 +99,6 @@ private:
oop _referent;
OopClosure* _keep_alive;
BoolObjectClosure* _is_alive;
bool _discovered_list_needs_post_barrier;
DEBUG_ONLY(
oop _first_seen; // cyclic linked list check
@ -113,8 +112,7 @@ private:
public:
inline DiscoveredListIterator(DiscoveredList& refs_list,
OopClosure* keep_alive,
BoolObjectClosure* is_alive,
bool discovered_list_needs_post_barrier = false):
BoolObjectClosure* is_alive):
_refs_list(refs_list),
_prev_next(refs_list.adr_head()),
_prev(NULL),
@ -128,8 +126,7 @@ public:
#endif
_next(NULL),
_keep_alive(keep_alive),
_is_alive(is_alive),
_discovered_list_needs_post_barrier(discovered_list_needs_post_barrier)
_is_alive(is_alive)
{ }
// End Of List.
@ -230,14 +227,6 @@ class ReferenceProcessor : public CHeapObj<mtGC> {
// other collectors in configuration
bool _discovery_is_mt; // true if reference discovery is MT.
// If true, setting "next" field of a discovered refs list requires
// write post barrier. (Must be true if used in a collector in which
// elements of a discovered list may be moved during discovery: for
// example, a collector like Garbage-First that moves objects during a
// long-term concurrent marking phase that does weak reference
// discovery.)
bool _discovered_list_needs_post_barrier;
bool _enqueuing_is_done; // true if all weak references enqueued
bool _processing_is_mt; // true during phases when
// reference processing is MT.
@ -382,11 +371,6 @@ class ReferenceProcessor : public CHeapObj<mtGC> {
void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor);
protected:
// Set the 'discovered' field of the given reference to
// the given value - emitting post barriers depending upon
// the value of _discovered_list_needs_post_barrier.
void set_discovered(oop ref, oop value);
// "Preclean" the given discovered reference list
// by removing references with strongly reachable referents.
// Currently used in support of CMS only.
@ -427,8 +411,7 @@ class ReferenceProcessor : public CHeapObj<mtGC> {
bool mt_processing = false, uint mt_processing_degree = 1,
bool mt_discovery = false, uint mt_discovery_degree = 1,
bool atomic_discovery = true,
BoolObjectClosure* is_alive_non_header = NULL,
bool discovered_list_needs_post_barrier = false);
BoolObjectClosure* is_alive_non_header = NULL);
// RefDiscoveryPolicy values
enum DiscoveryPolicy {