--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -44,52 +44,12 @@
   bool lock_owned = lock->owned_by_self();
   if (lock_owned) {
     MutexUnlocker mul(lock);
-    return mem_allocate_work(size);
+    return mem_allocate_in_gen(size, _gen);
   } else {
-    return mem_allocate_work(size);
+    return mem_allocate_in_gen(size, _gen);
   }
 }
 
-HeapWord* CMSPermGen::mem_allocate_work(size_t size) {
-  assert(!_gen->freelistLock()->owned_by_self(), "Potetntial deadlock");
-
-  MutexLocker ml(Heap_lock);
-  HeapWord* obj = NULL;
-
-  obj = _gen->allocate(size, false);
-  // Since we want to minimize pause times, we will prefer
-  // expanding the perm gen rather than doing a stop-world
-  // collection to satisfy the allocation request.
-  if (obj == NULL) {
-    // Try to expand the perm gen and allocate space.
-    obj = _gen->expand_and_allocate(size, false, false);
-    if (obj == NULL) {
-      // Let's see if a normal stop-world full collection will
-      // free up enough space.
-      SharedHeap::heap()->collect_locked(GCCause::_permanent_generation_full);
-      obj = _gen->allocate(size, false);
-      if (obj == NULL) {
-        // The collection above may have shrunk the space, so try
-        // to expand again and allocate space.
-        obj = _gen->expand_and_allocate(size, false, false);
-      }
-      if (obj == NULL) {
-        // We have not been able to allocate space despite a
-        // full stop-world collection. We now make a last-ditch collection
-        // attempt (in which soft refs are all aggressively freed)
-        // that will try to reclaim as much space as possible.
-        SharedHeap::heap()->collect_locked(GCCause::_last_ditch_collection);
-        obj = _gen->allocate(size, false);
-        if (obj == NULL) {
-          // Expand generation in case it was shrunk following the collection.
-          obj = _gen->expand_and_allocate(size, false, false);
-        }
-      }
-    }
-  }
-  return obj;
-}
-
 void CMSPermGen::compute_new_size() {
   _gen->compute_new_size();
 }

--- a/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.hpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/cmsPermGen.hpp	Tue Apr 01 15:13:47 2008 +0400
@@ -29,7 +29,6 @@
 class CMSPermGen:  public PermGen {
   friend class VMStructs;
 
-  HeapWord* mem_allocate_work(size_t size);
  protected:
   // The "generation" view.
   ConcurrentMarkSweepGeneration* _gen;

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -590,6 +590,31 @@
       full_gc_count = Universe::heap()->total_full_collections();
 
       result = perm_gen()->allocate_permanent(size);
+
+      if (result != NULL) {
+        return result;
+      }
+
+      if (GC_locker::is_active_and_needs_gc()) {
+        // If this thread is not in a jni critical section, we stall
+        // the requestor until the critical section has cleared and
+        // GC allowed. When the critical section clears, a GC is
+        // initiated by the last thread exiting the critical section; so
+        // we retry the allocation sequence from the beginning of the loop,
+        // rather than causing more, now probably unnecessary, GC attempts.
+        JavaThread* jthr = JavaThread::current();
+        if (!jthr->in_critical()) {
+          MutexUnlocker mul(Heap_lock);
+          GC_locker::stall_until_clear();
+          continue;
+        } else {
+          if (CheckJNICalls) {
+            fatal("Possible deadlock due to allocating while"
+                  " in jni critical section");
+          }
+          return NULL;
+        }
+      }
     }
 
     if (result == NULL) {
@@ -622,6 +647,12 @@
       if (op.prologue_succeeded()) {
         assert(Universe::heap()->is_in_permanent_or_null(op.result()),
           "result not in heap");
+        // If GC was locked out during VM operation then retry allocation
+        // and/or stall as necessary.
+        if (op.gc_locked()) {
+          assert(op.result() == NULL, "must be NULL if gc_locked() is true");
+          continue;  // retry and/or stall as necessary
+        }
         // If a NULL results is being returned, an out-of-memory
         // will be thrown now.  Clear the gc_time_limit_exceeded
         // flag to avoid the following situation.

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -999,7 +999,7 @@
   DEBUG_ONLY(mark_bitmap_count = mark_bitmap_size = 0;)
 
   // Increment the invocation count
-  heap->increment_total_collections();
+  heap->increment_total_collections(true);
 
   // We need to track unique mark sweep invocations as well.
   _total_invocations++;
@@ -1964,7 +1964,7 @@
   assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
   assert(ref_processor() != NULL, "Sanity");
 
-  if (GC_locker::is_active()) {
+  if (GC_locker::check_active_before_gc()) {
     return;
   }
 

--- a/hotspot/src/share/vm/gc_implementation/parallelScavenge/vmPSOperations.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/parallelScavenge/vmPSOperations.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -69,6 +69,9 @@
 
   GCCauseSetter gccs(heap, _gc_cause);
   _result = heap->failed_permanent_mem_allocate(_size);
+  if (_result == NULL && GC_locker::is_active_and_needs_gc()) {
+    set_gc_locked();
+  }
   notify_gc_end();
 }
 

--- a/hotspot/src/share/vm/gc_implementation/shared/vmGCOperations.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/shared/vmGCOperations.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -144,3 +144,18 @@
   gch->do_full_collection(gch->must_clear_all_soft_refs(), _max_level);
   notify_gc_end();
 }
+
+void VM_GenCollectForPermanentAllocation::doit() {
+  JvmtiGCForAllocationMarker jgcm;
+  notify_gc_begin(true);
+  GenCollectedHeap* gch = GenCollectedHeap::heap();
+  GCCauseSetter gccs(gch, _gc_cause);
+  gch->do_full_collection(gch->must_clear_all_soft_refs(),
+                          gch->n_gens() - 1);
+  _res = gch->perm_gen()->allocate(_size, false);
+  assert(gch->is_in_reserved_or_null(_res), "result not in heap");
+  if (_res == NULL && GC_locker::is_active_and_needs_gc()) {
+    set_gc_locked();
+  }
+  notify_gc_end();
+}

--- a/hotspot/src/share/vm/gc_implementation/shared/vmGCOperations.hpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/gc_implementation/shared/vmGCOperations.hpp	Tue Apr 01 15:13:47 2008 +0400
@@ -43,6 +43,7 @@
 //     is specified; and also the attach "inspectheap" operation
 //
 //  VM_GenCollectForAllocation
+//  VM_GenCollectForPermanentAllocation
 //  VM_ParallelGCFailedAllocation
 //  VM_ParallelGCFailedPermanentAllocation
 //   - this operation is invoked when allocation is failed;
@@ -166,3 +167,23 @@
   virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
   virtual void doit();
 };
+
+class VM_GenCollectForPermanentAllocation: public VM_GC_Operation {
+ private:
+  HeapWord*   _res;
+  size_t      _size;                       // size of object to be allocated
+ public:
+  VM_GenCollectForPermanentAllocation(size_t size,
+                                      unsigned int gc_count_before,
+                                      unsigned int full_gc_count_before,
+                                      GCCause::Cause gc_cause)
+    : VM_GC_Operation(gc_count_before, full_gc_count_before, true),
+      _size(size) {
+    _res = NULL;
+    _gc_cause = gc_cause;
+  }
+  ~VM_GenCollectForPermanentAllocation()  {}
+  virtual VMOp_Type type() const { return VMOp_GenCollectForPermanentAllocation; }
+  virtual void doit();
+  HeapWord* result() const       { return _res; }
+};

--- a/hotspot/src/share/vm/includeDB_core	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/includeDB_core	Tue Apr 01 15:13:47 2008 +0400
@@ -719,6 +719,11 @@
 ciObjArray.cpp                          ciUtilities.hpp
 ciObjArray.cpp                          objArrayOop.hpp
 
+ciObjArray.cpp                          ciObjArray.hpp
+ciObjArray.cpp                          ciNullObject.hpp
+ciObjArray.cpp                          ciUtilities.hpp
+ciObjArray.cpp                          objArrayOop.hpp
+
 ciObjArrayKlass.cpp                     ciInstanceKlass.hpp
 ciObjArrayKlass.cpp                     ciObjArrayKlass.hpp
 ciObjArrayKlass.cpp                     ciObjArrayKlassKlass.hpp
@@ -1636,6 +1641,7 @@
 
 gcLocker.cpp                            gcLocker.inline.hpp
 gcLocker.cpp                            sharedHeap.hpp
+gcLocker.cpp                            resourceArea.hpp
 
 gcLocker.hpp                            collectedHeap.hpp
 gcLocker.hpp                            genCollectedHeap.hpp
@@ -3061,13 +3067,14 @@
 oopMap.cpp                              signature.hpp
 
 oopMap.hpp                              allocation.hpp
+oopMapCache.cpp                         jvmtiRedefineClassesTrace.hpp
 oopMap.hpp                              compressedStream.hpp
 oopMap.hpp                              growableArray.hpp
 oopMap.hpp                              vmreg.hpp
 
 oopMapCache.cpp                         allocation.inline.hpp
+oopMapCache.cpp                         jvmtiRedefineClassesTrace.hpp
 oopMapCache.cpp                         handles.inline.hpp
-oopMapCache.cpp                         jvmtiRedefineClassesTrace.hpp
 oopMapCache.cpp                         oop.inline.hpp
 oopMapCache.cpp                         oopMapCache.hpp
 oopMapCache.cpp                         resourceArea.hpp
@@ -3315,6 +3322,10 @@
 permGen.cpp                             oop.inline.hpp
 permGen.cpp                             permGen.hpp
 permGen.cpp                             universe.hpp
+permGen.cpp                             gcLocker.hpp
+permGen.cpp                             gcLocker.inline.hpp
+permGen.cpp                             vmGCOperations.hpp
+permGen.cpp                             vmThread.hpp
 
 permGen.hpp                             gcCause.hpp
 permGen.hpp                             generation.hpp

--- a/hotspot/src/share/vm/memory/gcLocker.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/memory/gcLocker.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -32,6 +32,12 @@
 
 void GC_locker::stall_until_clear() {
   assert(!JavaThread::current()->in_critical(), "Would deadlock");
+  if (PrintJNIGCStalls && PrintGCDetails) {
+    ResourceMark rm; // JavaThread::name() allocates to convert to UTF8
+    gclog_or_tty->print_cr(
+      "Allocation failed. Thread \"%s\" is stalled by JNI critical section.",
+      JavaThread::current()->name());
+  }
   MutexLocker   ml(JNICritical_lock);
   // Wait for _needs_gc  to be cleared
   while (GC_locker::needs_gc()) {

--- a/hotspot/src/share/vm/memory/genCollectedHeap.hpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/memory/genCollectedHeap.hpp	Tue Apr 01 15:13:47 2008 +0400
@@ -35,6 +35,7 @@
   friend class CMSCollector;
   friend class GenMarkSweep;
   friend class VM_GenCollectForAllocation;
+  friend class VM_GenCollectForPermanentAllocation;
   friend class VM_GenCollectFull;
   friend class VM_GenCollectFullConcurrent;
   friend class VM_GC_HeapInspection;

--- a/hotspot/src/share/vm/memory/permGen.cpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/memory/permGen.cpp	Tue Apr 01 15:13:47 2008 +0400
@@ -25,6 +25,70 @@
 #include "incls/_precompiled.incl"
 #include "incls/_permGen.cpp.incl"
 
+HeapWord* PermGen::mem_allocate_in_gen(size_t size, Generation* gen) {
+  MutexLocker ml(Heap_lock);
+  GCCause::Cause next_cause = GCCause::_permanent_generation_full;
+  GCCause::Cause prev_cause = GCCause::_no_gc;
+
+  for (;;) {
+    HeapWord* obj = gen->allocate(size, false);
+    if (obj != NULL) {
+      return obj;
+    }
+    if (gen->capacity() < _capacity_expansion_limit ||
+        prev_cause != GCCause::_no_gc) {
+      obj = gen->expand_and_allocate(size, false);
+    }
+    if (obj == NULL && prev_cause != GCCause::_last_ditch_collection) {
+      if (GC_locker::is_active_and_needs_gc()) {
+        // If this thread is not in a jni critical section, we stall
+        // the requestor until the critical section has cleared and
+        // GC allowed. When the critical section clears, a GC is
+        // initiated by the last thread exiting the critical section; so
+        // we retry the allocation sequence from the beginning of the loop,
+        // rather than causing more, now probably unnecessary, GC attempts.
+        JavaThread* jthr = JavaThread::current();
+        if (!jthr->in_critical()) {
+          MutexUnlocker mul(Heap_lock);
+          // Wait for JNI critical section to be exited
+          GC_locker::stall_until_clear();
+          continue;
+        } else {
+          if (CheckJNICalls) {
+            fatal("Possible deadlock due to allocating while"
+                  " in jni critical section");
+          }
+          return NULL;
+        }
+      }
+
+      // Read the GC count while holding the Heap_lock
+      unsigned int gc_count_before      = SharedHeap::heap()->total_collections();
+      unsigned int full_gc_count_before = SharedHeap::heap()->total_full_collections();
+      {
+        MutexUnlocker mu(Heap_lock);  // give up heap lock, execute gets it back
+        VM_GenCollectForPermanentAllocation op(size, gc_count_before, full_gc_count_before,
+                                               next_cause);
+        VMThread::execute(&op);
+        if (!op.prologue_succeeded() || op.gc_locked()) {
+          assert(op.result() == NULL, "must be NULL if gc_locked() is true");
+          continue;  // retry and/or stall as necessary
+        }
+        obj = op.result();
+        assert(obj == NULL || SharedHeap::heap()->is_in_reserved(obj),
+               "result not in heap");
+        if (obj != NULL) {
+          return obj;
+        }
+      }
+      prev_cause = next_cause;
+      next_cause = GCCause::_last_ditch_collection;
+    } else {
+      return obj;
+    }
+  }
+}
+
 CompactingPermGen::CompactingPermGen(ReservedSpace rs,
                                      ReservedSpace shared_rs,
                                      size_t initial_byte_size,
@@ -44,40 +108,7 @@
 }
 
 HeapWord* CompactingPermGen::mem_allocate(size_t size) {
-  MutexLocker ml(Heap_lock);
-  HeapWord* obj = _gen->allocate(size, false);
-  bool tried_collection = false;
-  bool tried_expansion = false;
-  while (obj == NULL) {
-    if (_gen->capacity() >= _capacity_expansion_limit || tried_expansion) {
-      // Expansion limit reached, try collection before expanding further
-      // For now we force a full collection, this could be changed
-      SharedHeap::heap()->collect_locked(GCCause::_permanent_generation_full);
-      obj = _gen->allocate(size, false);
-      tried_collection = true;
-      tried_expansion =  false;    // ... following the collection:
-                                   // the collection may have shrunk the space.
-    }
-    if (obj == NULL && !tried_expansion) {
-      obj = _gen->expand_and_allocate(size, false);
-      tried_expansion = true;
-    }
-    if (obj == NULL && tried_collection && tried_expansion) {
-      // We have not been able to allocate despite a collection and
-      // an attempted space expansion. We now make a last-ditch collection
-      // attempt that will try to reclaim as much space as possible (for
-      // example by aggressively clearing all soft refs).
-      SharedHeap::heap()->collect_locked(GCCause::_last_ditch_collection);
-      obj = _gen->allocate(size, false);
-      if (obj == NULL) {
-        // An expansion attempt is necessary since the previous
-        // collection may have shrunk the space.
-        obj = _gen->expand_and_allocate(size, false);
-      }
-      break;
-    }
-  }
-  return obj;
+  return mem_allocate_in_gen(size, _gen);
 }
 
 void CompactingPermGen::compute_new_size() {

--- a/hotspot/src/share/vm/memory/permGen.hpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/memory/permGen.hpp	Tue Apr 01 15:13:47 2008 +0400
@@ -38,6 +38,8 @@
   size_t _capacity_expansion_limit;  // maximum expansion allowed without a
                                      // full gc occuring
 
+  HeapWord* mem_allocate_in_gen(size_t size, Generation* gen);
+
  public:
   enum Name {
     MarkSweepCompact, MarkSweep, ConcurrentMarkSweep

--- a/hotspot/src/share/vm/runtime/globals.hpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/runtime/globals.hpp	Tue Apr 01 15:13:47 2008 +0400
@@ -1919,6 +1919,10 @@
   develop(bool, IgnoreLibthreadGPFault, false,                              \
           "Suppress workaround for libthread GP fault")                     \
                                                                             \
+  product(bool, PrintJNIGCStalls, false,                                    \
+          "Print diagnostic message when GC is stalled"                     \
+          "by JNI critical section")                                        \
+                                                                            \
   /* JVMTI heap profiling */                                                \
                                                                             \
   diagnostic(bool, TraceJVMTIObjectTagging, false,                          \

--- a/hotspot/src/share/vm/runtime/vm_operations.hpp	Thu Mar 27 17:22:06 2008 -0700
+++ b/hotspot/src/share/vm/runtime/vm_operations.hpp	Tue Apr 01 15:13:47 2008 +0400
@@ -49,6 +49,7 @@
   template(GenCollectFull)                        \
   template(GenCollectFullConcurrent)              \
   template(GenCollectForAllocation)               \
+  template(GenCollectForPermanentAllocation)      \
   template(ParallelGCFailedAllocation)            \
   template(ParallelGCFailedPermanentAllocation)   \
   template(ParallelGCSystemGC)                    \