cshapiro@google.com
716c14a2a2
The scavenger now reports survival and promotion statistics. The statistics for the large free list are now reported. Previously, only information about the small free list was printed. Each report indicates whether the data is from before or after a garbage collection, each row of a report is preceded by the free list type (small or large), and cumulative bytes are reported for the free list type. Review URL: https://codereview.chromium.org//11416384 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@16074 260f80e4-7a28-3924-810f-c04153c831b5
109 lines
2.7 KiB
C++
109 lines
2.7 KiB
C++
// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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#ifndef VM_FREELIST_H_
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#define VM_FREELIST_H_
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#include "platform/assert.h"
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#include "vm/allocation.h"
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#include "vm/bit_set.h"
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#include "vm/raw_object.h"
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namespace dart {
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// FreeListElement describes a freelist element. Smallest FreeListElement is
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// two words in size. Second word of the raw object is used to keep a next_
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// pointer to chain elements of the list together. For objects larger than the
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// object size encodable in tags field, the size of the element is embedded in
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// the element at the address following the next_ field.
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class FreeListElement {
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public:
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FreeListElement* next() const {
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return next_;
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}
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void set_next(FreeListElement* next) {
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next_ = next;
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}
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intptr_t Size() {
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intptr_t size = RawObject::SizeTag::decode(tags_);
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if (size != 0) return size;
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return *SizeAddress();
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}
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static FreeListElement* AsElement(uword addr, intptr_t size);
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static void InitOnce();
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// Used to allocate class for free list elements in Object::InitOnce.
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class FakeInstance {
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public:
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FakeInstance() { }
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static cpp_vtable vtable() { return 0; }
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static intptr_t InstanceSize() { return 0; }
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static const ClassId kClassId = kFreeListElement;
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static bool IsInstance() { return true; }
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private:
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DISALLOW_ALLOCATION();
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DISALLOW_COPY_AND_ASSIGN(FakeInstance);
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};
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private:
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// This layout mirrors the layout of RawObject.
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uword tags_;
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FreeListElement* next_;
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// Returns the address of the embedded size.
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intptr_t* SizeAddress() const {
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uword addr = reinterpret_cast<uword>(&next_) + kWordSize;
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return reinterpret_cast<intptr_t*>(addr);
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}
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// FreeListElements cannot be allocated. Instead references to them are
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// created using the AsElement factory method.
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DISALLOW_ALLOCATION();
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DISALLOW_IMPLICIT_CONSTRUCTORS(FreeListElement);
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};
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class FreeList {
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public:
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FreeList();
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~FreeList();
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uword TryAllocate(intptr_t size);
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void Free(uword addr, intptr_t size);
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void Reset();
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intptr_t Length(int index) const;
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void Print() const;
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private:
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static const int kNumLists = 128;
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static intptr_t IndexForSize(intptr_t size);
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void EnqueueElement(FreeListElement* element, intptr_t index);
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FreeListElement* DequeueElement(intptr_t index);
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void SplitElementAfterAndEnqueue(FreeListElement* element, intptr_t size);
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void PrintSmall() const;
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void PrintLarge() const;
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BitSet<kNumLists> free_map_;
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FreeListElement* free_lists_[kNumLists + 1];
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DISALLOW_COPY_AND_ASSIGN(FreeList);
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};
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} // namespace dart
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#endif // VM_FREELIST_H_
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