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| 1 // Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
| 4 | 4 |
| 5 #include "vm/gc_sweeper.h" | 5 #include "vm/gc_sweeper.h" |
| 6 | 6 |
| 7 #include "vm/freelist.h" | 7 #include "vm/freelist.h" |
| 8 #include "vm/globals.h" | 8 #include "vm/globals.h" |
| 9 #include "vm/heap.h" | 9 #include "vm/heap.h" |
| 10 #include "vm/pages.h" | 10 #include "vm/pages.h" |
| 11 | 11 |
| 12 namespace dart { | 12 namespace dart { |
| 13 | 13 |
| 14 intptr_t GCSweeper::SweepPage(HeapPage* page, FreeList* freelist) { | 14 bool GCSweeper::SweepPage(HeapPage* page, FreeList* freelist) { |
| 15 // Keep track of the discovered live object sizes to be able to finish | 15 // Keep track of the discovered live object sizes to be able to finish |
|
koda
2014/04/24 23:09:56
Update comment; we are not tracking sizes here.
Ivan Posva
2014/04/24 23:17:50
Done.
| |
| 16 // sweeping early. Reset the per page in_use count for the next marking phase. | 16 // sweeping early. |
| 17 intptr_t in_use = 0; | 17 bool in_use = false; |
| 18 | 18 |
| 19 bool is_executable = (page->type() == HeapPage::kExecutable); | 19 bool is_executable = (page->type() == HeapPage::kExecutable); |
| 20 uword start = page->object_start(); | 20 uword start = page->object_start(); |
| 21 uword end = page->object_end(); | 21 uword end = page->object_end(); |
| 22 uword current = start; | 22 uword current = start; |
| 23 | 23 |
| 24 while (current < end) { | 24 while (current < end) { |
| 25 intptr_t obj_size; | 25 intptr_t obj_size; |
| 26 RawObject* raw_obj = RawObject::FromAddr(current); | 26 RawObject* raw_obj = RawObject::FromAddr(current); |
| 27 if (raw_obj->IsMarked()) { | 27 if (raw_obj->IsMarked()) { |
| 28 // Found marked object. Clear the mark bit and update swept bytes. | 28 // Found marked object. Clear the mark bit and update swept bytes. |
| 29 raw_obj->ClearMarkBit(); | 29 raw_obj->ClearMarkBit(); |
| 30 obj_size = raw_obj->Size(); | 30 obj_size = raw_obj->Size(); |
| 31 in_use += obj_size; | 31 in_use = true; |
| 32 } else { | 32 } else { |
| 33 uword free_end = current + raw_obj->Size(); | 33 uword free_end = current + raw_obj->Size(); |
| 34 while (free_end < end) { | 34 while (free_end < end) { |
| 35 RawObject* next_obj = RawObject::FromAddr(free_end); | 35 RawObject* next_obj = RawObject::FromAddr(free_end); |
| 36 if (next_obj->IsMarked()) { | 36 if (next_obj->IsMarked()) { |
| 37 // Reached the end of the free block. | 37 // Reached the end of the free block. |
| 38 break; | 38 break; |
| 39 } | 39 } |
| 40 // Expand the free block by the size of this object. | 40 // Expand the free block by the size of this object. |
| 41 free_end += next_obj->Size(); | 41 free_end += next_obj->Size(); |
| 42 } | 42 } |
| 43 obj_size = free_end - current; | 43 obj_size = free_end - current; |
| 44 if (is_executable) { | 44 if (is_executable) { |
| 45 memset(reinterpret_cast<void*>(current), 0xcc, obj_size); | 45 memset(reinterpret_cast<void*>(current), 0xcc, obj_size); |
| 46 } | 46 } |
| 47 if ((current != start) || (free_end != end)) { | 47 if ((current != start) || (free_end != end)) { |
| 48 // Only add to the free list if not covering the whole page. | 48 // Only add to the free list if not covering the whole page. |
| 49 freelist->Free(current, obj_size); | 49 freelist->Free(current, obj_size); |
| 50 } | 50 } |
| 51 } | 51 } |
| 52 current += obj_size; | 52 current += obj_size; |
| 53 } | 53 } |
| 54 ASSERT(current == end); | 54 ASSERT(current == end); |
| 55 | 55 |
| 56 return in_use; | 56 return in_use; |
| 57 } | 57 } |
| 58 | 58 |
| 59 | 59 |
| 60 intptr_t GCSweeper::SweepLargePage(HeapPage* page) { | 60 bool GCSweeper::SweepLargePage(HeapPage* page) { |
| 61 RawObject* raw_obj = RawObject::FromAddr(page->object_start()); | 61 RawObject* raw_obj = RawObject::FromAddr(page->object_start()); |
| 62 if (!raw_obj->IsMarked()) { | 62 if (!raw_obj->IsMarked()) { |
| 63 // The large object was not marked. Used size is zero, which also tells the | 63 // The large object was not marked. Used size is zero, which also tells the |
| 64 // calling code that the large object page can be recycled. | 64 // calling code that the large object page can be recycled. |
| 65 return 0; | 65 return false; |
| 66 } | 66 } |
| 67 raw_obj->ClearMarkBit(); | 67 raw_obj->ClearMarkBit(); |
| 68 return raw_obj->Size(); | 68 return true; |
| 69 } | 69 } |
| 70 | 70 |
| 71 } // namespace dart | 71 } // namespace dart |
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