8038404: Move object_iterate_mem from Space to CMS since it is only ever used by CMS

Reviewed-by: brutisso, tschatzl, stefank

hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.cpp

@@ -851,7 +851,58 @@ void CompactibleFreeListSpace::object_iterate_mem(MemRegion mr,
                                                   UpwardsObjectClosure* cl) {
   assert_locked(freelistLock());
   NOT_PRODUCT(verify_objects_initialized());
-  Space::object_iterate_mem(mr, cl);
+  assert(!mr.is_empty(), "Should be non-empty");
+  // We use MemRegion(bottom(), end()) rather than used_region() below
+  // because the two are not necessarily equal for some kinds of
+  // spaces, in particular, certain kinds of free list spaces.
+  // We could use the more complicated but more precise:
+  // MemRegion(used_region().start(), round_to(used_region().end(), CardSize))
+  // but the slight imprecision seems acceptable in the assertion check.
+  assert(MemRegion(bottom(), end()).contains(mr),
+         "Should be within used space");
+  HeapWord* prev = cl->previous();   // max address from last time
+  if (prev >= mr.end()) { // nothing to do
+    return;
+  }
+  // This assert will not work when we go from cms space to perm
+  // space, and use same closure. Easy fix deferred for later. XXX YSR
+  // assert(prev == NULL || contains(prev), "Should be within space");
+
+  bool last_was_obj_array = false;
+  HeapWord *blk_start_addr, *region_start_addr;
+  if (prev > mr.start()) {
+    region_start_addr = prev;
+    blk_start_addr    = prev;
+    // The previous invocation may have pushed "prev" beyond the
+    // last allocated block yet there may be still be blocks
+    // in this region due to a particular coalescing policy.
+    // Relax the assertion so that the case where the unallocated
+    // block is maintained and "prev" is beyond the unallocated
+    // block does not cause the assertion to fire.
+    assert((BlockOffsetArrayUseUnallocatedBlock &&
+            (!is_in(prev))) ||
+           (blk_start_addr == block_start(region_start_addr)), "invariant");
+  } else {
+    region_start_addr = mr.start();
+    blk_start_addr    = block_start(region_start_addr);
+  }
+  HeapWord* region_end_addr = mr.end();
+  MemRegion derived_mr(region_start_addr, region_end_addr);
+  while (blk_start_addr < region_end_addr) {
+    const size_t size = block_size(blk_start_addr);
+    if (block_is_obj(blk_start_addr)) {
+      last_was_obj_array = cl->do_object_bm(oop(blk_start_addr), derived_mr);
+    } else {
+      last_was_obj_array = false;
+    }
+    blk_start_addr += size;
+  }
+  if (!last_was_obj_array) {
+    assert((bottom() <= blk_start_addr) && (blk_start_addr <= end()),
+           "Should be within (closed) used space");
+    assert(blk_start_addr > prev, "Invariant");
+    cl->set_previous(blk_start_addr); // min address for next time
+  }
 }
 
 // Callers of this iterator beware: The closure application should

hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/compactibleFreeListSpace.hpp

@@ -363,6 +363,12 @@ class CompactibleFreeListSpace: public CompactibleSpace {
   // obj_is_alive() to determine whether it is safe to iterate of
   // an object.
   void safe_object_iterate(ObjectClosure* blk);
+
+  // Iterate over all objects that intersect with mr, calling "cl->do_object"
+  // on each.  There is an exception to this: if this closure has already
+  // been invoked on an object, it may skip such objects in some cases.  This is
+  // Most likely to happen in an "upwards" (ascending address) iteration of
+  // MemRegions.
   void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
 
   // Requires that "mr" be entirely within the space.

hotspot/src/share/vm/gc_implementation/concurrentMarkSweep/concurrentMarkSweepGeneration.hpp

@@ -1498,6 +1498,19 @@ class FalseBitMapClosure: public BitMapClosure {
   }
 };
 
+// A version of ObjectClosure with "memory" (see _previous_address below)
+class UpwardsObjectClosure: public BoolObjectClosure {
+  HeapWord* _previous_address;
+ public:
+  UpwardsObjectClosure() : _previous_address(NULL) { }
+  void set_previous(HeapWord* addr) { _previous_address = addr; }
+  HeapWord* previous()              { return _previous_address; }
+  // A return value of "true" can be used by the caller to decide
+  // if this object's end should *NOT* be recorded in
+  // _previous_address above.
+  virtual bool do_object_bm(oop obj, MemRegion mr) = 0;
+};
+
 // This closure is used during the second checkpointing phase
 // to rescan the marked objects on the dirty cards in the mod
 // union table and the card table proper. It's invoked via

hotspot/src/share/vm/memory/iterator.hpp

@@ -177,19 +177,6 @@ public:
   ObjectToOopClosure(ExtendedOopClosure* cl) : _cl(cl) {}
 };
 
-// A version of ObjectClosure with "memory" (see _previous_address below)
-class UpwardsObjectClosure: public BoolObjectClosure {
-  HeapWord* _previous_address;
- public:
-  UpwardsObjectClosure() : _previous_address(NULL) { }
-  void set_previous(HeapWord* addr) { _previous_address = addr; }
-  HeapWord* previous()              { return _previous_address; }
-  // A return value of "true" can be used by the caller to decide
-  // if this object's end should *NOT* be recorded in
-  // _previous_address above.
-  virtual bool do_object_bm(oop obj, MemRegion mr) = 0;
-};
-
 // A version of ObjectClosure that is expected to be robust
 // in the face of possibly uninitialized objects.
 class ObjectClosureCareful : public ObjectClosure {

hotspot/src/share/vm/memory/space.cpp

@@ -558,104 +558,11 @@ HeapWord* Space::object_iterate_careful_m(MemRegion mr,
   return bottom();
 }
 
-
-void Space::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
-  assert(!mr.is_empty(), "Should be non-empty");
-  // We use MemRegion(bottom(), end()) rather than used_region() below
-  // because the two are not necessarily equal for some kinds of
-  // spaces, in particular, certain kinds of free list spaces.
-  // We could use the more complicated but more precise:
-  // MemRegion(used_region().start(), round_to(used_region().end(), CardSize))
-  // but the slight imprecision seems acceptable in the assertion check.
-  assert(MemRegion(bottom(), end()).contains(mr),
-         "Should be within used space");
-  HeapWord* prev = cl->previous();   // max address from last time
-  if (prev >= mr.end()) { // nothing to do
-    return;
-  }
-  // This assert will not work when we go from cms space to perm
-  // space, and use same closure. Easy fix deferred for later. XXX YSR
-  // assert(prev == NULL || contains(prev), "Should be within space");
-
-  bool last_was_obj_array = false;
-  HeapWord *blk_start_addr, *region_start_addr;
-  if (prev > mr.start()) {
-    region_start_addr = prev;
-    blk_start_addr    = prev;
-    // The previous invocation may have pushed "prev" beyond the
-    // last allocated block yet there may be still be blocks
-    // in this region due to a particular coalescing policy.
-    // Relax the assertion so that the case where the unallocated
-    // block is maintained and "prev" is beyond the unallocated
-    // block does not cause the assertion to fire.
-    assert((BlockOffsetArrayUseUnallocatedBlock &&
-            (!is_in(prev))) ||
-           (blk_start_addr == block_start(region_start_addr)), "invariant");
-  } else {
-    region_start_addr = mr.start();
-    blk_start_addr    = block_start(region_start_addr);
-  }
-  HeapWord* region_end_addr = mr.end();
-  MemRegion derived_mr(region_start_addr, region_end_addr);
-  while (blk_start_addr < region_end_addr) {
-    const size_t size = block_size(blk_start_addr);
-    if (block_is_obj(blk_start_addr)) {
-      last_was_obj_array = cl->do_object_bm(oop(blk_start_addr), derived_mr);
-    } else {
-      last_was_obj_array = false;
-    }
-    blk_start_addr += size;
-  }
-  if (!last_was_obj_array) {
-    assert((bottom() <= blk_start_addr) && (blk_start_addr <= end()),
-           "Should be within (closed) used space");
-    assert(blk_start_addr > prev, "Invariant");
-    cl->set_previous(blk_start_addr); // min address for next time
-  }
-}
-
 bool Space::obj_is_alive(const HeapWord* p) const {
   assert (block_is_obj(p), "The address should point to an object");
   return true;
 }
 
-void ContiguousSpace::object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl) {
-  assert(!mr.is_empty(), "Should be non-empty");
-  assert(used_region().contains(mr), "Should be within used space");
-  HeapWord* prev = cl->previous();   // max address from last time
-  if (prev >= mr.end()) { // nothing to do
-    return;
-  }
-  // See comment above (in more general method above) in case you
-  // happen to use this method.
-  assert(prev == NULL || is_in_reserved(prev), "Should be within space");
-
-  bool last_was_obj_array = false;
-  HeapWord *obj_start_addr, *region_start_addr;
-  if (prev > mr.start()) {
-    region_start_addr = prev;
-    obj_start_addr    = prev;
-    assert(obj_start_addr == block_start(region_start_addr), "invariant");
-  } else {
-    region_start_addr = mr.start();
-    obj_start_addr    = block_start(region_start_addr);
-  }
-  HeapWord* region_end_addr = mr.end();
-  MemRegion derived_mr(region_start_addr, region_end_addr);
-  while (obj_start_addr < region_end_addr) {
-    oop obj = oop(obj_start_addr);
-    const size_t size = obj->size();
-    last_was_obj_array = cl->do_object_bm(obj, derived_mr);
-    obj_start_addr += size;
-  }
-  if (!last_was_obj_array) {
-    assert((bottom() <= obj_start_addr)  && (obj_start_addr <= end()),
-           "Should be within (closed) used space");
-    assert(obj_start_addr > prev, "Invariant");
-    cl->set_previous(obj_start_addr); // min address for next time
-  }
-}
-
 #if INCLUDE_ALL_GCS
 #define ContigSpace_PAR_OOP_ITERATE_DEFN(OopClosureType, nv_suffix)         \
                                                                             \

hotspot/src/share/vm/memory/space.hpp

@@ -204,13 +204,6 @@ class Space: public CHeapObj<mtGC> {
   // objects whose internal references point to objects in the space.
   virtual void safe_object_iterate(ObjectClosure* blk) = 0;
 
-  // Iterate over all objects that intersect with mr, calling "cl->do_object"
-  // on each.  There is an exception to this: if this closure has already
-  // been invoked on an object, it may skip such objects in some cases.  This is
-  // Most likely to happen in an "upwards" (ascending address) iteration of
-  // MemRegions.
-  virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
-
   // Iterate over as many initialized objects in the space as possible,
   // calling "cl.do_object_careful" on each. Return NULL if all objects
   // in the space (at the start of the iteration) were iterated over.
@@ -840,7 +833,6 @@ class ContiguousSpace: public CompactibleSpace {
   // For contiguous spaces this method will iterate safely over objects
   // in the space (i.e., between bottom and top) when at a safepoint.
   void safe_object_iterate(ObjectClosure* blk);
-  void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl);
   // iterates on objects up to the safe limit
   HeapWord* object_iterate_careful(ObjectClosureCareful* cl);
   HeapWord* concurrent_iteration_safe_limit() {