7036482: clear argument is redundant and unused in cardtable methods

Summary: Removed the unused clear argument to various cardtbale methods and unused mod_oop_in_space_iterate method. Unrelated to synopsis, added  a pair of clarifying parens in AllocationStats constructor.
Reviewed-by: brutisso, jcoomes

src/share/vm/gc_implementation/parNew/parCardTableModRefBS.cpp

 /*
- * Copyright (c) 2007, 2010 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2007, 2011 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
@@ -36,7 +36,6 @@
 void CardTableModRefBS::par_non_clean_card_iterate_work(Space* sp, MemRegion mr,
                                                         DirtyCardToOopClosure* dcto_cl,
                                                         MemRegionClosure* cl,
-                                                        bool clear,
                                                         int n_threads) {
   if (n_threads > 0) {
     assert((n_threads == 1 && ParallelGCThreads == 0) ||
@@ -57,7 +56,7 @@ void CardTableModRefBS::par_non_clean_card_iterate_work(Space* sp, MemRegion mr,
 
     int stride = 0;
     while (!pst->is_task_claimed(/* reference */ stride)) {
-      process_stride(sp, mr, stride, n_strides, dcto_cl, cl, clear,
+      process_stride(sp, mr, stride, n_strides, dcto_cl, cl,
                      lowest_non_clean,
                      lowest_non_clean_base_chunk_index,
                      lowest_non_clean_chunk_size);
@@ -83,7 +82,6 @@ process_stride(Space* sp,
                jint stride, int n_strides,
                DirtyCardToOopClosure* dcto_cl,
                MemRegionClosure* cl,
-               bool clear,
                jbyte** lowest_non_clean,
                uintptr_t lowest_non_clean_base_chunk_index,
                size_t    lowest_non_clean_chunk_size) {
@@ -129,7 +127,7 @@ process_stride(Space* sp,
                              lowest_non_clean_base_chunk_index,
                              lowest_non_clean_chunk_size);
 
-    non_clean_card_iterate_work(chunk_mr, cl, clear);
+    non_clean_card_iterate_work(chunk_mr, cl);
 
     // Find the next chunk of the stride.
     chunk_card_start += CardsPerStrideChunk * n_strides;

src/share/vm/gc_implementation/shared/allocationStats.hpp

@@ -76,7 +76,7 @@ class AllocationStats VALUE_OBJ_CLASS_SPEC {
     _beforeSweep = 0;
     _coalBirths = 0;
     _coalDeaths = 0;
-    _splitBirths = split_birth? 1 : 0;
+    _splitBirths = (split_birth ? 1 : 0);
     _splitDeaths = 0;
     _returnedBytes = 0;
   }

src/share/vm/memory/cardTableModRefBS.cpp

 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2011, 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
@@ -459,18 +459,17 @@ bool CardTableModRefBS::mark_card_deferred(size_t card_index) {
 void CardTableModRefBS::non_clean_card_iterate(Space* sp,
                                                MemRegion mr,
                                                DirtyCardToOopClosure* dcto_cl,
-                                               MemRegionClosure* cl,
-                                               bool clear) {
+                                               MemRegionClosure* cl) {
   if (!mr.is_empty()) {
     int n_threads = SharedHeap::heap()->n_par_threads();
     if (n_threads > 0) {
 #ifndef SERIALGC
-      par_non_clean_card_iterate_work(sp, mr, dcto_cl, cl, clear, n_threads);
+      par_non_clean_card_iterate_work(sp, mr, dcto_cl, cl, n_threads);
 #else  // SERIALGC
       fatal("Parallel gc not supported here.");
 #endif // SERIALGC
     } else {
-      non_clean_card_iterate_work(mr, cl, clear);
+      non_clean_card_iterate_work(mr, cl);
     }
   }
 }
@@ -481,10 +480,7 @@ void CardTableModRefBS::non_clean_card_iterate(Space* sp,
 // cards (and miss those marked precleaned). In that sense,
 // the name precleaned is currently somewhat of a misnomer.
 void CardTableModRefBS::non_clean_card_iterate_work(MemRegion mr,
-                                                    MemRegionClosure* cl,
-                                                    bool clear) {
-  // Figure out whether we have to worry about parallelism.
-  bool is_par = (SharedHeap::heap()->n_par_threads() > 1);
+                                                    MemRegionClosure* cl) {
   for (int i = 0; i < _cur_covered_regions; i++) {
     MemRegion mri = mr.intersection(_covered[i]);
     if (mri.word_size() > 0) {
@@ -506,22 +502,6 @@ void CardTableModRefBS::non_clean_card_iterate_work(MemRegion mr,
           MemRegion cur_cards(addr_for(cur_entry),
                               non_clean_cards * card_size_in_words);
           MemRegion dirty_region = cur_cards.intersection(mri);
-          if (clear) {
-            for (size_t i = 0; i < non_clean_cards; i++) {
-              // Clean the dirty cards (but leave the other non-clean
-              // alone.)  If parallel, do the cleaning atomically.
-              jbyte cur_entry_val = cur_entry[i];
-              if (card_is_dirty_wrt_gen_iter(cur_entry_val)) {
-                if (is_par) {
-                  jbyte res = Atomic::cmpxchg(clean_card, &cur_entry[i], cur_entry_val);
-                  assert(res != clean_card,
-                         "Dirty card mysteriously cleaned");
-                } else {
-                  cur_entry[i] = clean_card;
-                }
-              }
-            }
-          }
           cl->do_MemRegion(dirty_region);
         }
         cur_entry = next_entry;
@@ -530,22 +510,6 @@ void CardTableModRefBS::non_clean_card_iterate_work(MemRegion mr,
   }
 }
 
-void CardTableModRefBS::mod_oop_in_space_iterate(Space* sp,
-                                                 OopClosure* cl,
-                                                 bool clear,
-                                                 bool before_save_marks) {
-  // Note that dcto_cl is resource-allocated, so there is no
-  // corresponding "delete".
-  DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision());
-  MemRegion used_mr;
-  if (before_save_marks) {
-    used_mr = sp->used_region_at_save_marks();
-  } else {
-    used_mr = sp->used_region();
-  }
-  non_clean_card_iterate(sp, used_mr, dcto_cl, dcto_cl, clear);
-}
-
 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) {
   assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start");
   assert((HeapWord*)align_size_up  ((uintptr_t)mr.end(),   HeapWordSize) == mr.end(),   "Unaligned end"  );
@@ -593,9 +557,8 @@ void CardTableModRefBS::dirty(MemRegion mr) {
   memset(first, dirty_card, last-first);
 }
 
-// NOTES:
-// (1) Unlike mod_oop_in_space_iterate() above, dirty_card_iterate()
-//     iterates over dirty cards ranges in increasing address order.
+// Unlike several other card table methods, dirty_card_iterate()
+// iterates over dirty cards ranges in increasing address order.
 void CardTableModRefBS::dirty_card_iterate(MemRegion mr,
                                            MemRegionClosure* cl) {
   for (int i = 0; i < _cur_covered_regions; i++) {
@@ -698,7 +661,7 @@ public:
 
 void CardTableModRefBS::verify_clean_region(MemRegion mr) {
   GuaranteeNotModClosure blk(this);
-  non_clean_card_iterate_work(mr, &blk, false);
+  non_clean_card_iterate_work(mr, &blk);
 }
 
 // To verify a MemRegion is entirely dirty this closure is passed to

src/share/vm/memory/cardTableModRefBS.hpp

 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2011, 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
@@ -171,17 +171,14 @@ class CardTableModRefBS: public ModRefBarrierSet {
   // mode if worker threads are available.
   void non_clean_card_iterate(Space* sp, MemRegion mr,
                               DirtyCardToOopClosure* dcto_cl,
-                              MemRegionClosure* cl,
-                              bool clear);
+                              MemRegionClosure* cl);
 
   // Utility function used to implement the other versions below.
-  void non_clean_card_iterate_work(MemRegion mr, MemRegionClosure* cl,
-                                   bool clear);
+  void non_clean_card_iterate_work(MemRegion mr, MemRegionClosure* cl);
 
   void par_non_clean_card_iterate_work(Space* sp, MemRegion mr,
                                        DirtyCardToOopClosure* dcto_cl,
                                        MemRegionClosure* cl,
-                                       bool clear,
                                        int n_threads);
 
   // Dirty the bytes corresponding to "mr" (not all of which must be
@@ -241,7 +238,6 @@ class CardTableModRefBS: public ModRefBarrierSet {
                       jint stride, int n_strides,
                       DirtyCardToOopClosure* dcto_cl,
                       MemRegionClosure* cl,
-                      bool clear,
                       jbyte** lowest_non_clean,
                       uintptr_t lowest_non_clean_base_chunk_index,
                       size_t lowest_non_clean_chunk_size);
@@ -402,9 +398,6 @@ public:
   virtual void invalidate(MemRegion mr, bool whole_heap = false);
   void clear(MemRegion mr);
   void dirty(MemRegion mr);
-  void mod_oop_in_space_iterate(Space* sp, OopClosure* cl,
-                                bool clear = false,
-                                bool before_save_marks = false);
 
   // *** Card-table-RemSet-specific things.
 
@@ -415,18 +408,15 @@ public:
   // *decreasing* address order.  (This order aids with imprecise card
   // marking, where a dirty card may cause scanning, and summarization
   // marking, of objects that extend onto subsequent cards.)
-  // If "clear" is true, the card is (conceptually) marked unmodified before
-  // applying the closure.
-  void mod_card_iterate(MemRegionClosure* cl, bool clear = false) {
-    non_clean_card_iterate_work(_whole_heap, cl, clear);
+  void mod_card_iterate(MemRegionClosure* cl) {
+    non_clean_card_iterate_work(_whole_heap, cl);
   }
 
   // Like the "mod_cards_iterate" above, except only invokes the closure
   // for cards within the MemRegion "mr" (which is required to be
   // card-aligned and sized.)
-  void mod_card_iterate(MemRegion mr, MemRegionClosure* cl,
-                        bool clear = false) {
-    non_clean_card_iterate_work(mr, cl, clear);
+  void mod_card_iterate(MemRegion mr, MemRegionClosure* cl) {
+    non_clean_card_iterate_work(mr, cl);
   }
 
   static uintx ct_max_alignment_constraint();

src/share/vm/memory/cardTableRS.cpp

 /*
- * Copyright (c) 2001, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2011, 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
@@ -247,7 +247,7 @@ void CardTableRS::younger_refs_in_space_iterate(Space* sp,
   ClearNoncleanCardWrapper clear_cl(dcto_cl, this);
 
   _ct_bs->non_clean_card_iterate(sp, sp->used_region_at_save_marks(),
-                                dcto_cl, &clear_cl, false);
+                                dcto_cl, &clear_cl);
 }
 
 void CardTableRS::clear_into_younger(Generation* gen, bool clear_perm) {

src/share/vm/memory/modRefBarrierSet.hpp

 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2011, 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
@@ -88,15 +88,6 @@ public:
     assert(false, "can't call");
   }
 
-  // Invoke "cl->do_oop" on (the address of) every possibly-modifed
-  // reference field in objects in "sp".  If "clear" is "true", the oops
-  // are no longer considered possibly modified after application of the
-  // closure.  If' "before_save_marks" is true, oops in objects allocated
-  // after the last call to "save_marks" on "sp" will not be considered.
-  virtual void mod_oop_in_space_iterate(Space* sp, OopClosure* cl,
-                                        bool clear = false,
-                                        bool before_save_marks = false) = 0;
-
   // Causes all refs in "mr" to be assumed to be modified.  If "whole_heap"
   // is true, the caller asserts that the entire heap is being invalidated,
   // which may admit an optimized implementation for some barriers.