7144296: PS: Optimize nmethods processing

Summary: Prunes scavenge roots in code list every young GC, promote objects directly pointed by the code immediately
Reviewed-by: johnc, jcoomes

src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.cpp

 /*
- * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -247,167 +247,6 @@ void PSPromotionManager::flush_labs() {
   }
 }
 
-//
-// This method is pretty bulky. It would be nice to split it up
-// into smaller submethods, but we need to be careful not to hurt
-// performance.
-//
-
-oop PSPromotionManager::copy_to_survivor_space(oop o) {
-  assert(PSScavenge::should_scavenge(&o), "Sanity");
-
-  oop new_obj = NULL;
-
-  // NOTE! We must be very careful with any methods that access the mark
-  // in o. There may be multiple threads racing on it, and it may be forwarded
-  // at any time. Do not use oop methods for accessing the mark!
-  markOop test_mark = o->mark();
-
-  // The same test as "o->is_forwarded()"
-  if (!test_mark->is_marked()) {
-    bool new_obj_is_tenured = false;
-    size_t new_obj_size = o->size();
-
-    // Find the objects age, MT safe.
-    int age = (test_mark->has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
-      test_mark->displaced_mark_helper()->age() : test_mark->age();
-
-    // Try allocating obj in to-space (unless too old)
-    if (age < PSScavenge::tenuring_threshold()) {
-      new_obj = (oop) _young_lab.allocate(new_obj_size);
-      if (new_obj == NULL && !_young_gen_is_full) {
-        // Do we allocate directly, or flush and refill?
-        if (new_obj_size > (YoungPLABSize / 2)) {
-          // Allocate this object directly
-          new_obj = (oop)young_space()->cas_allocate(new_obj_size);
-        } else {
-          // Flush and fill
-          _young_lab.flush();
-
-          HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
-          if (lab_base != NULL) {
-            _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
-            // Try the young lab allocation again.
-            new_obj = (oop) _young_lab.allocate(new_obj_size);
-          } else {
-            _young_gen_is_full = true;
-          }
-        }
-      }
-    }
-
-    // Otherwise try allocating obj tenured
-    if (new_obj == NULL) {
-#ifndef PRODUCT
-      if (Universe::heap()->promotion_should_fail()) {
-        return oop_promotion_failed(o, test_mark);
-      }
-#endif  // #ifndef PRODUCT
-
-      new_obj = (oop) _old_lab.allocate(new_obj_size);
-      new_obj_is_tenured = true;
-
-      if (new_obj == NULL) {
-        if (!_old_gen_is_full) {
-          // Do we allocate directly, or flush and refill?
-          if (new_obj_size > (OldPLABSize / 2)) {
-            // Allocate this object directly
-            new_obj = (oop)old_gen()->cas_allocate(new_obj_size);
-          } else {
-            // Flush and fill
-            _old_lab.flush();
-
-            HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);
-            if(lab_base != NULL) {
-              _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
-              // Try the old lab allocation again.
-              new_obj = (oop) _old_lab.allocate(new_obj_size);
-            }
-          }
-        }
-
-        // This is the promotion failed test, and code handling.
-        // The code belongs here for two reasons. It is slightly
-        // different thatn the code below, and cannot share the
-        // CAS testing code. Keeping the code here also minimizes
-        // the impact on the common case fast path code.
-
-        if (new_obj == NULL) {
-          _old_gen_is_full = true;
-          return oop_promotion_failed(o, test_mark);
-        }
-      }
-    }
-
-    assert(new_obj != NULL, "allocation should have succeeded");
-
-    // Copy obj
-    Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)new_obj, new_obj_size);
-
-    // Now we have to CAS in the header.
-    if (o->cas_forward_to(new_obj, test_mark)) {
-      // We won any races, we "own" this object.
-      assert(new_obj == o->forwardee(), "Sanity");
-
-      // Increment age if obj still in new generation. Now that
-      // we're dealing with a markOop that cannot change, it is
-      // okay to use the non mt safe oop methods.
-      if (!new_obj_is_tenured) {
-        new_obj->incr_age();
-        assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
-      }
-
-      // Do the size comparison first with new_obj_size, which we
-      // already have. Hopefully, only a few objects are larger than
-      // _min_array_size_for_chunking, and most of them will be arrays.
-      // So, the is->objArray() test would be very infrequent.
-      if (new_obj_size > _min_array_size_for_chunking &&
-          new_obj->is_objArray() &&
-          PSChunkLargeArrays) {
-        // we'll chunk it
-        oop* const masked_o = mask_chunked_array_oop(o);
-        push_depth(masked_o);
-        TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_masked_pushes);
-      } else {
-        // we'll just push its contents
-        new_obj->push_contents(this);
-      }
-    }  else {
-      // We lost, someone else "owns" this object
-      guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");
-
-      // Try to deallocate the space.  If it was directly allocated we cannot
-      // deallocate it, so we have to test.  If the deallocation fails,
-      // overwrite with a filler object.
-      if (new_obj_is_tenured) {
-        if (!_old_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
-          CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
-        }
-      } else if (!_young_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
-        CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
-      }
-
-      // don't update this before the unallocation!
-      new_obj = o->forwardee();
-    }
-  } else {
-    assert(o->is_forwarded(), "Sanity");
-    new_obj = o->forwardee();
-  }
-
-#ifdef DEBUG
-  // This code must come after the CAS test, or it will print incorrect
-  // information.
-  if (TraceScavenge) {
-    gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (" SIZE_FORMAT ")}",
-       PSScavenge::should_scavenge(&new_obj) ? "copying" : "tenuring",
-       new_obj->blueprint()->internal_name(), o, new_obj, new_obj->size());
-  }
-#endif
-
-  return new_obj;
-}
-
 template <class T> void PSPromotionManager::process_array_chunk_work(
                                                  oop obj,
                                                  int start, int end) {

src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.hpp

 /*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -171,7 +171,7 @@ class PSPromotionManager : public CHeapObj {
   void set_old_gen_is_full(bool state) { _old_gen_is_full = state; }
 
   // Promotion methods
-  oop copy_to_survivor_space(oop o);
+  template<bool promote_immediately> oop copy_to_survivor_space(oop o);
   oop oop_promotion_failed(oop obj, markOop obj_mark);
 
   void reset();

src/share/vm/gc_implementation/parallelScavenge/psPromotionManager.inline.hpp

 /*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -61,6 +61,170 @@ inline void PSPromotionManager::claim_or_forward_depth(T* p) {
   claim_or_forward_internal_depth(p);
 }
 
+//
+// This method is pretty bulky. It would be nice to split it up
+// into smaller submethods, but we need to be careful not to hurt
+// performance.
+//
+template<bool promote_immediately>
+oop PSPromotionManager::copy_to_survivor_space(oop o) {
+  assert(PSScavenge::should_scavenge(&o), "Sanity");
+
+  oop new_obj = NULL;
+
+  // NOTE! We must be very careful with any methods that access the mark
+  // in o. There may be multiple threads racing on it, and it may be forwarded
+  // at any time. Do not use oop methods for accessing the mark!
+  markOop test_mark = o->mark();
+
+  // The same test as "o->is_forwarded()"
+  if (!test_mark->is_marked()) {
+    bool new_obj_is_tenured = false;
+    size_t new_obj_size = o->size();
+
+    if (!promote_immediately) {
+      // Find the objects age, MT safe.
+      int age = (test_mark->has_displaced_mark_helper() /* o->has_displaced_mark() */) ?
+        test_mark->displaced_mark_helper()->age() : test_mark->age();
+
+      // Try allocating obj in to-space (unless too old)
+      if (age < PSScavenge::tenuring_threshold()) {
+        new_obj = (oop) _young_lab.allocate(new_obj_size);
+        if (new_obj == NULL && !_young_gen_is_full) {
+          // Do we allocate directly, or flush and refill?
+          if (new_obj_size > (YoungPLABSize / 2)) {
+            // Allocate this object directly
+            new_obj = (oop)young_space()->cas_allocate(new_obj_size);
+          } else {
+            // Flush and fill
+            _young_lab.flush();
+
+            HeapWord* lab_base = young_space()->cas_allocate(YoungPLABSize);
+            if (lab_base != NULL) {
+              _young_lab.initialize(MemRegion(lab_base, YoungPLABSize));
+              // Try the young lab allocation again.
+              new_obj = (oop) _young_lab.allocate(new_obj_size);
+            } else {
+              _young_gen_is_full = true;
+            }
+          }
+        }
+      }
+    }
+
+    // Otherwise try allocating obj tenured
+    if (new_obj == NULL) {
+#ifndef PRODUCT
+      if (Universe::heap()->promotion_should_fail()) {
+        return oop_promotion_failed(o, test_mark);
+      }
+#endif  // #ifndef PRODUCT
+
+      new_obj = (oop) _old_lab.allocate(new_obj_size);
+      new_obj_is_tenured = true;
+
+      if (new_obj == NULL) {
+        if (!_old_gen_is_full) {
+          // Do we allocate directly, or flush and refill?
+          if (new_obj_size > (OldPLABSize / 2)) {
+            // Allocate this object directly
+            new_obj = (oop)old_gen()->cas_allocate(new_obj_size);
+          } else {
+            // Flush and fill
+            _old_lab.flush();
+
+            HeapWord* lab_base = old_gen()->cas_allocate(OldPLABSize);
+            if(lab_base != NULL) {
+              _old_lab.initialize(MemRegion(lab_base, OldPLABSize));
+              // Try the old lab allocation again.
+              new_obj = (oop) _old_lab.allocate(new_obj_size);
+            }
+          }
+        }
+
+        // This is the promotion failed test, and code handling.
+        // The code belongs here for two reasons. It is slightly
+        // different thatn the code below, and cannot share the
+        // CAS testing code. Keeping the code here also minimizes
+        // the impact on the common case fast path code.
+
+        if (new_obj == NULL) {
+          _old_gen_is_full = true;
+          return oop_promotion_failed(o, test_mark);
+        }
+      }
+    }
+
+    assert(new_obj != NULL, "allocation should have succeeded");
+
+    // Copy obj
+    Copy::aligned_disjoint_words((HeapWord*)o, (HeapWord*)new_obj, new_obj_size);
+
+    // Now we have to CAS in the header.
+    if (o->cas_forward_to(new_obj, test_mark)) {
+      // We won any races, we "own" this object.
+      assert(new_obj == o->forwardee(), "Sanity");
+
+      // Increment age if obj still in new generation. Now that
+      // we're dealing with a markOop that cannot change, it is
+      // okay to use the non mt safe oop methods.
+      if (!new_obj_is_tenured) {
+        new_obj->incr_age();
+        assert(young_space()->contains(new_obj), "Attempt to push non-promoted obj");
+      }
+
+      // Do the size comparison first with new_obj_size, which we
+      // already have. Hopefully, only a few objects are larger than
+      // _min_array_size_for_chunking, and most of them will be arrays.
+      // So, the is->objArray() test would be very infrequent.
+      if (new_obj_size > _min_array_size_for_chunking &&
+          new_obj->is_objArray() &&
+          PSChunkLargeArrays) {
+        // we'll chunk it
+        oop* const masked_o = mask_chunked_array_oop(o);
+        push_depth(masked_o);
+        TASKQUEUE_STATS_ONLY(++_arrays_chunked; ++_masked_pushes);
+      } else {
+        // we'll just push its contents
+        new_obj->push_contents(this);
+      }
+    }  else {
+      // We lost, someone else "owns" this object
+      guarantee(o->is_forwarded(), "Object must be forwarded if the cas failed.");
+
+      // Try to deallocate the space.  If it was directly allocated we cannot
+      // deallocate it, so we have to test.  If the deallocation fails,
+      // overwrite with a filler object.
+      if (new_obj_is_tenured) {
+        if (!_old_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
+          CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
+        }
+      } else if (!_young_lab.unallocate_object((HeapWord*) new_obj, new_obj_size)) {
+        CollectedHeap::fill_with_object((HeapWord*) new_obj, new_obj_size);
+      }
+
+      // don't update this before the unallocation!
+      new_obj = o->forwardee();
+    }
+  } else {
+    assert(o->is_forwarded(), "Sanity");
+    new_obj = o->forwardee();
+  }
+
+#ifdef DEBUG
+  // This code must come after the CAS test, or it will print incorrect
+  // information.
+  if (TraceScavenge) {
+    gclog_or_tty->print_cr("{%s %s " PTR_FORMAT " -> " PTR_FORMAT " (" SIZE_FORMAT ")}",
+       PSScavenge::should_scavenge(&new_obj) ? "copying" : "tenuring",
+       new_obj->blueprint()->internal_name(), o, new_obj, new_obj->size());
+  }
+#endif
+
+  return new_obj;
+}
+
+
 inline void PSPromotionManager::process_popped_location_depth(StarTask p) {
   if (is_oop_masked(p)) {
     assert(PSChunkLargeArrays, "invariant");
@@ -69,9 +233,9 @@ inline void PSPromotionManager::process_popped_location_depth(StarTask p) {
   } else {
     if (p.is_narrow()) {
       assert(UseCompressedOops, "Error");
-      PSScavenge::copy_and_push_safe_barrier(this, (narrowOop*)p);
+      PSScavenge::copy_and_push_safe_barrier<narrowOop, /*promote_immediately=*/false>(this, p);
     } else {
-      PSScavenge::copy_and_push_safe_barrier(this, (oop*)p);
+      PSScavenge::copy_and_push_safe_barrier<oop, /*promote_immediately=*/false>(this, p);
     }
   }
 }

src/share/vm/gc_implementation/parallelScavenge/psScavenge.cpp

@@ -24,6 +24,7 @@
 
 #include "precompiled.hpp"
 #include "classfile/symbolTable.hpp"
+#include "code/codeCache.hpp"
 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
 #include "gc_implementation/parallelScavenge/generationSizer.hpp"
@@ -100,7 +101,7 @@ public:
 
     // Weak refs may be visited more than once.
     if (PSScavenge::should_scavenge(p, _to_space)) {
-      PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p);
+      PSScavenge::copy_and_push_safe_barrier<T, /*promote_immediately=*/false>(_promotion_manager, p);
     }
   }
   virtual void do_oop(oop* p)       { PSKeepAliveClosure::do_oop_work(p); }
@@ -602,6 +603,8 @@ bool PSScavenge::invoke_no_policy() {
 
     NOT_PRODUCT(reference_processor()->verify_no_references_recorded());
 
+    CodeCache::prune_scavenge_root_nmethods();
+
     // Re-verify object start arrays
     if (VerifyObjectStartArray &&
         VerifyAfterGC) {

src/share/vm/gc_implementation/parallelScavenge/psScavenge.hpp

 /*
- * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -135,7 +135,8 @@ class PSScavenge: AllStatic {
   template <class T> static inline bool should_scavenge(T* p, MutableSpace* to_space);
   template <class T> static inline bool should_scavenge(T* p, bool check_to_space);
 
-  template <class T> inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p);
+  template <class T, bool promote_immediately>
+    inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p);
 
   // Is an object in the young generation
   // This assumes that the HeapWord argument is in the heap,

src/share/vm/gc_implementation/parallelScavenge/psScavenge.inline.hpp

 /*
- * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -28,6 +28,7 @@
 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp"
 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
 #include "gc_implementation/parallelScavenge/psPromotionManager.hpp"
+#include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
 
 inline void PSScavenge::save_to_space_top_before_gc() {
@@ -65,7 +66,7 @@ inline bool PSScavenge::should_scavenge(T* p, bool check_to_space) {
 // Attempt to "claim" oop at p via CAS, push the new obj if successful
 // This version tests the oop* to make sure it is within the heap before
 // attempting marking.
-template <class T>
+template <class T, bool promote_immediately>
 inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,
                                                    T*                  p) {
   assert(should_scavenge(p, true), "revisiting object?");
@@ -73,7 +74,7 @@ inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,
   oop o = oopDesc::load_decode_heap_oop_not_null(p);
   oop new_obj = o->is_forwarded()
         ? o->forwardee()
-        : pm->copy_to_survivor_space(o);
+        : pm->copy_to_survivor_space<promote_immediately>(o);
   oopDesc::encode_store_heap_oop_not_null(p, new_obj);
 
   // We cannot mark without test, as some code passes us pointers
@@ -86,7 +87,8 @@ inline void PSScavenge::copy_and_push_safe_barrier(PSPromotionManager* pm,
   }
 }
 
-class PSScavengeRootsClosure: public OopClosure {
+template<bool promote_immediately>
+class PSRootsClosure: public OopClosure {
  private:
   PSPromotionManager* _promotion_manager;
 
@@ -94,13 +96,16 @@ class PSScavengeRootsClosure: public OopClosure {
   template <class T> void do_oop_work(T *p) {
     if (PSScavenge::should_scavenge(p)) {
       // We never card mark roots, maybe call a func without test?
-      PSScavenge::copy_and_push_safe_barrier(_promotion_manager, p);
+      PSScavenge::copy_and_push_safe_barrier<T, promote_immediately>(_promotion_manager, p);
     }
   }
  public:
-  PSScavengeRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
-  void do_oop(oop* p)       { PSScavengeRootsClosure::do_oop_work(p); }
-  void do_oop(narrowOop* p) { PSScavengeRootsClosure::do_oop_work(p); }
+  PSRootsClosure(PSPromotionManager* pm) : _promotion_manager(pm) { }
+  void do_oop(oop* p)       { PSRootsClosure::do_oop_work(p); }
+  void do_oop(narrowOop* p) { PSRootsClosure::do_oop_work(p); }
 };
 
+typedef PSRootsClosure</*promote_immediately=*/false> PSScavengeRootsClosure;
+typedef PSRootsClosure</*promote_immediately=*/true> PSPromoteRootsClosure;
+
 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_INLINE_HPP

src/share/vm/gc_implementation/parallelScavenge/psTasks.cpp

 /*
- * Copyright (c) 2002, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2002, 2012, 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
@@ -51,6 +51,7 @@ void ScavengeRootsTask::do_it(GCTaskManager* manager, uint which) {
 
   PSPromotionManager* pm = PSPromotionManager::gc_thread_promotion_manager(which);
   PSScavengeRootsClosure roots_closure(pm);
+  PSPromoteRootsClosure  roots_to_old_closure(pm);
 
   switch (_root_type) {
     case universe:
@@ -91,7 +92,7 @@ void ScavengeRootsTask::do_it(GCTaskManager* manager, uint which) {
 
     case code_cache:
       {
-        CodeBlobToOopClosure each_scavengable_code_blob(&roots_closure, /*do_marking=*/ true);
+        CodeBlobToOopClosure each_scavengable_code_blob(&roots_to_old_closure, /*do_marking=*/ true);
         CodeCache::scavenge_root_nmethods_do(&each_scavengable_code_blob);
       }
       break;