Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "card_table.h" |
| 18 | |
Elliott Hughes | a168c83 | 2012-06-12 15:34:20 -0700 | [diff] [blame] | 19 | #include <dynamic_annotations.h> |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 20 | |
| 21 | #include "heap.h" |
| 22 | #include "heap_bitmap.h" |
| 23 | #include "logging.h" |
Elliott Hughes | b3bd5f0 | 2012-03-08 21:05:27 -0800 | [diff] [blame] | 24 | #include "runtime.h" |
Mathieu Chartier | 262e5ff | 2012-06-01 17:35:38 -0700 | [diff] [blame] | 25 | #include "space.h" |
Elliott Hughes | f0605a0 | 2012-01-13 20:12:02 -0800 | [diff] [blame] | 26 | #include "utils.h" |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 27 | |
| 28 | namespace art { |
| 29 | /* |
| 30 | * Maintain a card table from the write barrier. All writes of |
| 31 | * non-NULL values to heap addresses should go through an entry in |
| 32 | * WriteBarrier, and from there to here. |
| 33 | * |
| 34 | * The heap is divided into "cards" of GC_CARD_SIZE bytes, as |
| 35 | * determined by GC_CARD_SHIFT. The card table contains one byte of |
| 36 | * data per card, to be used by the GC. The value of the byte will be |
| 37 | * one of GC_CARD_CLEAN or GC_CARD_DIRTY. |
| 38 | * |
| 39 | * After any store of a non-NULL object pointer into a heap object, |
| 40 | * code is obliged to mark the card dirty. The setters in |
| 41 | * object.h [such as SetFieldObject] do this for you. The |
| 42 | * compiler also contains code to mark cards as dirty. |
| 43 | * |
| 44 | * The card table's base [the "biased card table"] gets set to a |
| 45 | * rather strange value. In order to keep the JIT from having to |
| 46 | * fabricate or load GC_DIRTY_CARD to store into the card table, |
| 47 | * biased base is within the mmap allocation at a point where its low |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 48 | * byte is equal to GC_DIRTY_CARD. See CardTable::Create for details. |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 49 | */ |
| 50 | |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 51 | CardTable* CardTable::Create(const byte* heap_begin, size_t heap_capacity) { |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 52 | /* Set up the card table */ |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 53 | size_t capacity = heap_capacity / kCardSize; |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 54 | /* Allocate an extra 256 bytes to allow fixed low-byte of base */ |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 55 | UniquePtr<MemMap> mem_map(MemMap::MapAnonymous("dalvik-card-table", NULL, |
| 56 | capacity + 256, PROT_READ | PROT_WRITE)); |
jeffhao | 8161c03 | 2012-10-31 15:50:00 -0700 | [diff] [blame^] | 57 | CHECK(mem_map.get() != NULL) << "couldn't allocate card table"; |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 58 | // All zeros is the correct initial value; all clean. Anonymous mmaps are initialized to zero, we |
| 59 | // don't clear the card table to avoid unnecessary pages being allocated |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 60 | COMPILE_ASSERT(kCardClean == 0, card_clean_must_be_0); |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 61 | |
| 62 | byte* cardtable_begin = mem_map->Begin(); |
| 63 | CHECK(cardtable_begin != NULL); |
| 64 | |
| 65 | // We allocated up to a bytes worth of extra space to allow biased_begin's byte value to equal |
| 66 | // GC_CARD_DIRTY, compute a offset value to make this the case |
| 67 | size_t offset = 0; |
Elliott Hughes | 398f64b | 2012-03-26 18:05:48 -0700 | [diff] [blame] | 68 | byte* biased_begin = reinterpret_cast<byte*>(reinterpret_cast<uintptr_t>(cardtable_begin) - |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 69 | (reinterpret_cast<uintptr_t>(heap_begin) >> kCardShift)); |
| 70 | if (((uintptr_t)biased_begin & 0xff) != kCardDirty) { |
| 71 | int delta = kCardDirty - (reinterpret_cast<int>(biased_begin) & 0xff); |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 72 | offset = delta + (delta < 0 ? 0x100 : 0); |
| 73 | biased_begin += offset; |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 74 | } |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 75 | CHECK_EQ(reinterpret_cast<int>(biased_begin) & 0xff, kCardDirty); |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 76 | |
| 77 | return new CardTable(mem_map.release(), biased_begin, offset); |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 78 | } |
| 79 | |
Elliott Hughes | a168c83 | 2012-06-12 15:34:20 -0700 | [diff] [blame] | 80 | CardTable::CardTable(MemMap* mem_map, byte* biased_begin, size_t offset) |
| 81 | : mem_map_(mem_map), biased_begin_(biased_begin), offset_(offset) { |
| 82 | byte* __attribute__((unused)) begin = mem_map_->Begin() + offset_; |
| 83 | byte* __attribute__((unused)) end = mem_map_->End(); |
| 84 | ANNOTATE_BENIGN_RACE_SIZED(begin, (end - begin), "writes to GC card table"); |
| 85 | } |
| 86 | |
Mathieu Chartier | 2fde533 | 2012-09-14 14:51:54 -0700 | [diff] [blame] | 87 | void CardTable::ClearSpaceCards(ContinuousSpace* space) { |
Mathieu Chartier | 262e5ff | 2012-06-01 17:35:38 -0700 | [diff] [blame] | 88 | // TODO: clear just the range of the table that has been modified |
Mathieu Chartier | cc236d7 | 2012-07-20 10:29:05 -0700 | [diff] [blame] | 89 | byte* card_start = CardFromAddr(space->Begin()); |
| 90 | byte* card_end = CardFromAddr(space->End()); // Make sure to round up. |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 91 | memset(reinterpret_cast<void*>(card_start), kCardClean, card_end - card_start); |
Mathieu Chartier | 262e5ff | 2012-06-01 17:35:38 -0700 | [diff] [blame] | 92 | } |
| 93 | |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 94 | void CardTable::ClearCardTable() { |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 95 | // TODO: clear just the range of the table that has been modified |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 96 | memset(mem_map_->Begin(), kCardClean, mem_map_->Size()); |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 97 | } |
| 98 | |
Mathieu Chartier | 2fde533 | 2012-09-14 14:51:54 -0700 | [diff] [blame] | 99 | void CardTable::PreClearCards(ContinuousSpace* space, std::vector<byte*>& out_cards) { |
Mathieu Chartier | 357e9be | 2012-08-01 11:00:14 -0700 | [diff] [blame] | 100 | byte* card_end = CardFromAddr(space->End()); |
| 101 | for (byte* card_cur = CardFromAddr(space->Begin()); card_cur < card_end; ++card_cur) { |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 102 | if (*card_cur == kCardDirty) { |
Mathieu Chartier | 357e9be | 2012-08-01 11:00:14 -0700 | [diff] [blame] | 103 | out_cards.push_back(card_cur); |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 104 | *card_cur = kCardClean; |
Mathieu Chartier | 357e9be | 2012-08-01 11:00:14 -0700 | [diff] [blame] | 105 | } |
| 106 | } |
| 107 | } |
| 108 | |
Mathieu Chartier | 2fde533 | 2012-09-14 14:51:54 -0700 | [diff] [blame] | 109 | void CardTable::GetDirtyCards(ContinuousSpace* space, std::vector<byte*>& out_cards) const { |
Mathieu Chartier | 357e9be | 2012-08-01 11:00:14 -0700 | [diff] [blame] | 110 | byte* card_end = CardFromAddr(space->End()); |
| 111 | for (byte* card_cur = CardFromAddr(space->Begin());card_cur < card_end; ++card_cur) { |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 112 | if (*card_cur == kCardDirty) { |
Mathieu Chartier | 357e9be | 2012-08-01 11:00:14 -0700 | [diff] [blame] | 113 | out_cards.push_back(card_cur); |
| 114 | } |
| 115 | } |
| 116 | } |
| 117 | |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 118 | bool CardTable::AddrIsInCardTable(const void* addr) const { |
| 119 | return IsValidCard(biased_begin_ + ((uintptr_t)addr >> kCardShift)); |
| 120 | } |
| 121 | |
Ian Rogers | 30fab40 | 2012-01-23 15:43:46 -0800 | [diff] [blame] | 122 | void CardTable::CheckAddrIsInCardTable(const byte* addr) const { |
Mathieu Chartier | 7469ebf | 2012-09-24 16:28:36 -0700 | [diff] [blame] | 123 | byte* card_addr = biased_begin_ + ((uintptr_t)addr >> kCardShift); |
| 124 | byte* begin = mem_map_->Begin() + offset_; |
| 125 | byte* end = mem_map_->End(); |
| 126 | CHECK(AddrIsInCardTable(addr)) |
| 127 | << "Card table " << this |
| 128 | << " begin: " << reinterpret_cast<void*>(begin) |
| 129 | << " end: " << reinterpret_cast<void*>(end) |
| 130 | << " card_addr: " << reinterpret_cast<void*>(card_addr) |
| 131 | << " heap begin: " << AddrFromCard(begin) |
| 132 | << " heap end: " << AddrFromCard(end) |
| 133 | << " addr: " << reinterpret_cast<const void*>(addr); |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 134 | } |
| 135 | |
Ian Rogers | 5d76c43 | 2011-10-31 21:42:49 -0700 | [diff] [blame] | 136 | void CardTable::VerifyCardTable() { |
| 137 | UNIMPLEMENTED(WARNING) << "Card table verification"; |
| 138 | } |
| 139 | |
| 140 | } // namespace art |