From 81554d51bf181f341cf6fd50390103424954ac19 Mon Sep 17 00:00:00 2001
From: jcoomes <unknown>
Date: Thu, 18 Mar 2010 13:31:51 -0700
Subject: [PATCH] 6935839: excessive marking stack growth during full gcs
 Summary: process one item at a time from the objarray stack/queue
 Reviewed-by: apetrusenko, tonyp

---
 .../parallelScavenge/psCompactionManager.cpp              | 8 ++++----
 src/share/vm/gc_implementation/shared/markSweep.cpp       | 3 ++-
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.cpp b/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.cpp
index a9723f3cd..c0dda2099 100644
--- a/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.cpp
+++ b/src/share/vm/gc_implementation/parallelScavenge/psCompactionManager.cpp
@@ -217,21 +217,21 @@ void ParCompactionManager::reset() {
 void ParCompactionManager::follow_marking_stacks() {
   do {
     // Drain the overflow stack first, to allow stealing from the marking stack.
+    oop obj;
     while (!overflow_stack()->is_empty()) {
       overflow_stack()->pop()->follow_contents(this);
     }
-    oop obj;
     while (marking_stack()->pop_local(obj)) {
       obj->follow_contents(this);
     }
 
+    // Process ObjArrays one at a time to avoid marking stack bloat.
     ObjArrayTask task;
-    while (!_objarray_overflow_stack->is_empty()) {
+    if (!_objarray_overflow_stack->is_empty()) {
       task = _objarray_overflow_stack->pop();
       objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
       k->oop_follow_contents(this, task.obj(), task.index());
-    }
-    while (_objarray_queue.pop_local(task)) {
+    } else if (_objarray_queue.pop_local(task)) {
       objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
       k->oop_follow_contents(this, task.obj(), task.index());
     }
diff --git a/src/share/vm/gc_implementation/shared/markSweep.cpp b/src/share/vm/gc_implementation/shared/markSweep.cpp
index 776730da7..d200fee44 100644
--- a/src/share/vm/gc_implementation/shared/markSweep.cpp
+++ b/src/share/vm/gc_implementation/shared/markSweep.cpp
@@ -111,7 +111,8 @@ void MarkSweep::follow_stack() {
       assert (obj->is_gc_marked(), "p must be marked");
       obj->follow_contents();
     }
-    while (!_objarray_stack->is_empty()) {
+    // Process ObjArrays one at a time to avoid marking stack bloat.
+    if (!_objarray_stack->is_empty()) {
       ObjArrayTask task = _objarray_stack->pop();
       objArrayKlass* const k = (objArrayKlass*)task.obj()->blueprint();
       k->oop_follow_contents(task.obj(), task.index());
-- 
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