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src/share/vm/gc/g1/g1ConcurrentMark.hpp
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rev 12511 : [mq]: 8168467-use-taskentry-as-mark-stack-elem
@@ -1,7 +1,7 @@
/*
- * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2017, 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
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -36,11 +36,59 @@
class G1CMTask;
class G1ConcurrentMark;
class ConcurrentGCTimer;
class G1OldTracer;
class G1SurvivorRegions;
-typedef GenericTaskQueue<oop, mtGC> G1CMTaskQueue;
+
+#ifdef _MSC_VER
+#pragma warning(push)
+// warning C4522: multiple assignment operators specified
+#pragma warning(disable:4522)
+#endif
+
+// This is a container class for either an oop or a continuation address for
+// mark stack entries. Both are pushed onto the mark stack.
+class G1TaskQueueEntry VALUE_OBJ_CLASS_SPEC {
+private:
+ void* _holder;
+
+ static const uintptr_t ArraySliceBit = 1;
+public:
+ G1TaskQueueEntry() : _holder(NULL) { }
+ G1TaskQueueEntry(oop obj) : _holder(obj) { }
+ G1TaskQueueEntry(HeapWord* addr) : _holder((void*)((uintptr_t)addr | ArraySliceBit)) { }
+
+ G1TaskQueueEntry& operator=(const G1TaskQueueEntry& t) {
+ _holder = t._holder;
+ return *this;
+ }
+
+ volatile G1TaskQueueEntry& operator=(const volatile G1TaskQueueEntry& t) volatile {
+ _holder = t._holder;
+ return *this;
+ }
+
+ oop obj() const {
+ assert(!is_array_slice(), "Trying to read array slice " PTR_FORMAT " as oop", p2i(_holder));
+ return (oop)_holder;
+ }
+
+ HeapWord* slice() const {
+ assert(is_array_slice(), "Trying to read oop " PTR_FORMAT " as array slice", p2i(_holder));
+ return (HeapWord*)((uintptr_t)_holder &~ ArraySliceBit);
+ }
+
+ bool is_oop() const { return !is_array_slice(); }
+ bool is_array_slice() const { return ((uintptr_t)_holder & ArraySliceBit) != 0; }
+ bool is_null() const { return _holder == NULL; }
+};
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+typedef GenericTaskQueue<G1TaskQueueEntry, mtGC> G1CMTaskQueue;
typedef GenericTaskQueueSet<G1CMTaskQueue, mtGC> G1CMTaskQueueSet;
// Closure used by CM during concurrent reference discovery
// and reference processing (during remarking) to determine
// if a particular object is alive. It is primarily used
@@ -164,15 +212,15 @@
// that all chunks at a lower address are valid chunks, and a singly linked free
// list connecting all empty chunks.
class G1CMMarkStack VALUE_OBJ_CLASS_SPEC {
public:
// Number of oops that can fit in a single chunk.
- static const size_t OopsPerChunk = 1024 - 1 /* One reference for the next pointer */;
+ static const size_t EntriesPerChunk = 1024 - 1 /* One reference for the next pointer */;
private:
struct OopChunk {
OopChunk* next;
- oop data[OopsPerChunk];
+ G1TaskQueueEntry data[EntriesPerChunk];
};
size_t _max_chunk_capacity; // Maximum number of OopChunk elements on the stack.
OopChunk* _base; // Bottom address of allocated memory area.
@@ -225,16 +273,16 @@
// Pushes the given buffer containing at most OopsPerChunk elements on the mark
// stack. If less than OopsPerChunk elements are to be pushed, the array must
// be terminated with a NULL.
// Returns whether the buffer contents were successfully pushed to the global mark
// stack.
- bool par_push_chunk(oop* buffer);
+ bool par_push_chunk(G1TaskQueueEntry* buffer);
// Pops a chunk from this mark stack, copying them into the given buffer. This
// chunk may contain up to OopsPerChunk elements. If there are less, the last
// element in the array is a NULL pointer.
- bool par_pop_chunk(oop* buffer);
+ bool par_pop_chunk(G1TaskQueueEntry* buffer);
// Return whether the chunk list is empty. Racy due to unsynchronized access to
// _chunk_list.
bool is_empty() const { return _chunk_list == NULL; }
@@ -249,11 +297,11 @@
// Expand the stack, typically in response to an overflow condition
void expand();
// Return the approximate number of oops on this mark stack. Racy due to
// unsynchronized access to _chunks_in_chunk_list.
- size_t size() const { return _chunks_in_chunk_list * OopsPerChunk; }
+ size_t size() const { return _chunks_in_chunk_list * EntriesPerChunk; }
void set_empty();
// Apply Fn to every oop on the mark stack. The mark stack must not
// be modified while iterating.
@@ -529,18 +577,18 @@
void clear_bitmap(G1CMBitMap* bitmap, WorkGang* workers, bool may_yield);
public:
// Manipulation of the global mark stack.
// The push and pop operations are used by tasks for transfers
// between task-local queues and the global mark stack.
- bool mark_stack_push(oop* arr) {
+ bool mark_stack_push(G1TaskQueueEntry* arr) {
if (!_global_mark_stack.par_push_chunk(arr)) {
set_has_overflown();
return false;
}
return true;
}
- bool mark_stack_pop(oop* arr) {
+ bool mark_stack_pop(G1TaskQueueEntry* arr) {
return _global_mark_stack.par_pop_chunk(arr);
}
size_t mark_stack_size() { return _global_mark_stack.size(); }
size_t partial_mark_stack_size_target() { return _global_mark_stack.capacity()/3; }
bool mark_stack_overflow() { return _global_mark_stack.is_out_of_memory(); }
@@ -571,11 +619,11 @@
ret += _accum_task_vtime[i];
return ret;
}
// Attempts to steal an object from the task queues of other tasks
- bool try_stealing(uint worker_id, int* hash_seed, oop& obj);
+ bool try_stealing(uint worker_id, int* hash_seed, G1TaskQueueEntry& task_entry);
G1ConcurrentMark(G1CollectedHeap* g1h,
G1RegionToSpaceMapper* prev_bitmap_storage,
G1RegionToSpaceMapper* next_bitmap_storage);
~G1ConcurrentMark();
@@ -826,11 +874,11 @@
// Test whether obj might have already been passed over by the
// mark bitmap scan, and so needs to be pushed onto the mark stack.
bool is_below_finger(oop obj, HeapWord* global_finger) const;
- template<bool scan> void process_grey_object(oop obj);
+ template<bool scan> void process_grey_object(G1TaskQueueEntry task_entry);
public:
// Apply the closure on the given area of the objArray. Return the number of words
// scanned.
inline size_t scan_objArray(objArrayOop obj, MemRegion mr);
// It resets the task; it should be called right at the beginning of
@@ -891,14 +939,14 @@
// e.g. obj is below its containing region's NTAMS.
// Precondition: obj is a valid heap object.
inline void deal_with_reference(oop obj);
// It scans an object and visits its children.
- inline void scan_object(oop obj);
+ inline void scan_object(G1TaskQueueEntry task_entry);
// It pushes an object on the local queue.
- inline void push(oop obj);
+ inline void push(G1TaskQueueEntry task_entry);
// Move entries to the global stack.
void move_entries_to_global_stack();
// Move entries from the global stack, return true if we were successful to do so.
bool get_entries_from_global_stack();
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