iposva@google.com
0d25bce528
- Sweep large pages. - Handle free list elements when calculating sizes. Review URL: http://codereview.chromium.org//8996011 git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@2593 260f80e4-7a28-3924-810f-c04153c831b5
74 lines
2.1 KiB
C++
74 lines
2.1 KiB
C++
// Copyright (c) 2011, 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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#include "vm/gc_sweeper.h"
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#include "vm/freelist.h"
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#include "vm/globals.h"
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#include "vm/pages.h"
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namespace dart {
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intptr_t GCSweeper::SweepPage(HeapPage* page, FreeList* freelist) {
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// Keep track of the discovered live object sizes to be able to finish
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// sweeping early. Reset the per page in_use count for the next marking phase.
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intptr_t in_use_swept = 0;
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intptr_t in_use = page->used();
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page->set_used(0);
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uword current = page->first_object_start();
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uword top = page->top();
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while (current < top) {
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if (in_use_swept == in_use) {
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// No more marked objects will be found on this page.
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page->set_top(current);
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break;
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}
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RawObject* raw_obj = RawObject::FromAddr(current);
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intptr_t obj_size;
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if (raw_obj->IsMarked()) {
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// Found marked object. Clear the mark bit and update swept bytes.
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raw_obj->ClearMarkBit();
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obj_size = raw_obj->Size();
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in_use_swept += obj_size;
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} else {
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uword free_end = current + raw_obj->Size();
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while (free_end < top) {
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RawObject* next_obj = RawObject::FromAddr(free_end);
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if (next_obj->IsMarked()) {
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// Reached the end of the free block.
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break;
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}
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// Expand the free block by the size of this object.
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free_end += next_obj->Size();
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}
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obj_size = free_end - current;
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if ((current + obj_size) == top) {
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page->set_top(current);
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break;
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} else {
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freelist->Free(current, obj_size);
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}
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}
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current += obj_size;
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}
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return in_use_swept;
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}
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intptr_t GCSweeper::SweepLargePage(HeapPage* page) {
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RawObject* raw_obj = RawObject::FromAddr(page->first_object_start());
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if (!raw_obj->IsMarked()) {
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// The large object was not marked. Used size is zero, which also tells the
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// calling code that the large object page can be recycled.
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return 0;
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}
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raw_obj->ClearMarkBit();
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return raw_obj->Size();
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}
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} // namespace dart
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