card_table.cc revision 2cebb24bfc3247d3e9be138a3350106737455918
15d76c435082332ef79a22962386fa92a0870e378Ian Rogers/* 25d76c435082332ef79a22962386fa92a0870e378Ian Rogers * Copyright (C) 2010 The Android Open Source Project 35d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 45d76c435082332ef79a22962386fa92a0870e378Ian Rogers * Licensed under the Apache License, Version 2.0 (the "License"); 55d76c435082332ef79a22962386fa92a0870e378Ian Rogers * you may not use this file except in compliance with the License. 65d76c435082332ef79a22962386fa92a0870e378Ian Rogers * You may obtain a copy of the License at 75d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 85d76c435082332ef79a22962386fa92a0870e378Ian Rogers * http://www.apache.org/licenses/LICENSE-2.0 95d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 105d76c435082332ef79a22962386fa92a0870e378Ian Rogers * Unless required by applicable law or agreed to in writing, software 115d76c435082332ef79a22962386fa92a0870e378Ian Rogers * distributed under the License is distributed on an "AS IS" BASIS, 125d76c435082332ef79a22962386fa92a0870e378Ian Rogers * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 135d76c435082332ef79a22962386fa92a0870e378Ian Rogers * See the License for the specific language governing permissions and 145d76c435082332ef79a22962386fa92a0870e378Ian Rogers * limitations under the License. 155d76c435082332ef79a22962386fa92a0870e378Ian Rogers */ 165d76c435082332ef79a22962386fa92a0870e378Ian Rogers 175d76c435082332ef79a22962386fa92a0870e378Ian Rogers#include "card_table.h" 185d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1907ed66b5ae659c452cbe1ab20c3dbf1d6f546461Elliott Hughes#include "base/logging.h" 201d54e73444e017d3a65234e0f193846f3e27472bIan Rogers#include "card_table-inl.h" 211d54e73444e017d3a65234e0f193846f3e27472bIan Rogers#include "gc/heap.h" 221d54e73444e017d3a65234e0f193846f3e27472bIan Rogers#include "gc/space/space.h" 235d76c435082332ef79a22962386fa92a0870e378Ian Rogers#include "heap_bitmap.h" 243481ba2c4e4f3aa80d8c6d50a9f85dacb56b508bVladimir Marko#include "mem_map.h" 25b3bd5f07884f5a1f2b84224363b1372d7c28d447Elliott Hughes#include "runtime.h" 26f0605a0da70a495521e466c98255d469915a1f00Elliott Hughes#include "utils.h" 275d76c435082332ef79a22962386fa92a0870e378Ian Rogers 285d76c435082332ef79a22962386fa92a0870e378Ian Rogersnamespace art { 291d54e73444e017d3a65234e0f193846f3e27472bIan Rogersnamespace gc { 301d54e73444e017d3a65234e0f193846f3e27472bIan Rogersnamespace accounting { 311d54e73444e017d3a65234e0f193846f3e27472bIan Rogers 322c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartierconstexpr size_t CardTable::kCardShift; 332c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartierconstexpr size_t CardTable::kCardSize; 342c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartierconstexpr uint8_t CardTable::kCardClean; 352c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartierconstexpr uint8_t CardTable::kCardDirty; 362c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier 375d76c435082332ef79a22962386fa92a0870e378Ian Rogers/* 385d76c435082332ef79a22962386fa92a0870e378Ian Rogers * Maintain a card table from the write barrier. All writes of 392cebb24bfc3247d3e9be138a3350106737455918Mathieu Chartier * non-null values to heap addresses should go through an entry in 405d76c435082332ef79a22962386fa92a0870e378Ian Rogers * WriteBarrier, and from there to here. 415d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 425d76c435082332ef79a22962386fa92a0870e378Ian Rogers * The heap is divided into "cards" of GC_CARD_SIZE bytes, as 435d76c435082332ef79a22962386fa92a0870e378Ian Rogers * determined by GC_CARD_SHIFT. The card table contains one byte of 445d76c435082332ef79a22962386fa92a0870e378Ian Rogers * data per card, to be used by the GC. The value of the byte will be 455d76c435082332ef79a22962386fa92a0870e378Ian Rogers * one of GC_CARD_CLEAN or GC_CARD_DIRTY. 465d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 472cebb24bfc3247d3e9be138a3350106737455918Mathieu Chartier * After any store of a non-null object pointer into a heap object, 485d76c435082332ef79a22962386fa92a0870e378Ian Rogers * code is obliged to mark the card dirty. The setters in 495d76c435082332ef79a22962386fa92a0870e378Ian Rogers * object.h [such as SetFieldObject] do this for you. The 505d76c435082332ef79a22962386fa92a0870e378Ian Rogers * compiler also contains code to mark cards as dirty. 515d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 525d76c435082332ef79a22962386fa92a0870e378Ian Rogers * The card table's base [the "biased card table"] gets set to a 535d76c435082332ef79a22962386fa92a0870e378Ian Rogers * rather strange value. In order to keep the JIT from having to 545d76c435082332ef79a22962386fa92a0870e378Ian Rogers * fabricate or load GC_DIRTY_CARD to store into the card table, 555d76c435082332ef79a22962386fa92a0870e378Ian Rogers * biased base is within the mmap allocation at a point where its low 5630fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers * byte is equal to GC_DIRTY_CARD. See CardTable::Create for details. 575d76c435082332ef79a22962386fa92a0870e378Ian Rogers */ 585d76c435082332ef79a22962386fa92a0870e378Ian Rogers 5913735955f39b3b304c37d2b2840663c131262c18Ian RogersCardTable* CardTable::Create(const uint8_t* heap_begin, size_t heap_capacity) { 605d76c435082332ef79a22962386fa92a0870e378Ian Rogers /* Set up the card table */ 617469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier size_t capacity = heap_capacity / kCardSize; 625d76c435082332ef79a22962386fa92a0870e378Ian Rogers /* Allocate an extra 256 bytes to allow fixed low-byte of base */ 638d31bbd3d6536de12bc20e3d29cfe03fe848f9daIan Rogers std::string error_msg; 642c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier std::unique_ptr<MemMap> mem_map( 652c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier MemMap::MapAnonymous("card table", nullptr, capacity + 256, PROT_READ | PROT_WRITE, 665c42c29b89286e5efa4a4613132b09051ce5945bVladimir Marko false, false, &error_msg)); 672cebb24bfc3247d3e9be138a3350106737455918Mathieu Chartier CHECK(mem_map.get() != nullptr) << "couldn't allocate card table: " << error_msg; 6830fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // All zeros is the correct initial value; all clean. Anonymous mmaps are initialized to zero, we 6930fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // don't clear the card table to avoid unnecessary pages being allocated 70575e78c41ece0dec969d31f46be563d4eb7ae43bAndreas Gampe static_assert(kCardClean == 0, "kCardClean must be 0"); 7130fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers 7213735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* cardtable_begin = mem_map->Begin(); 732cebb24bfc3247d3e9be138a3350106737455918Mathieu Chartier CHECK(cardtable_begin != nullptr); 7430fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers 7530fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // We allocated up to a bytes worth of extra space to allow biased_begin's byte value to equal 762c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier // kCardDirty, compute a offset value to make this the case 7730fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers size_t offset = 0; 7813735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* biased_begin = reinterpret_cast<uint8_t*>(reinterpret_cast<uintptr_t>(cardtable_begin) - 797469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier (reinterpret_cast<uintptr_t>(heap_begin) >> kCardShift)); 802c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier uintptr_t biased_byte = reinterpret_cast<uintptr_t>(biased_begin) & 0xff; 812c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier if (biased_byte != kCardDirty) { 822c26501d24d929abe096ecce44f91410290b33c0Mathieu Chartier int delta = kCardDirty - biased_byte; 8330fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers offset = delta + (delta < 0 ? 0x100 : 0); 8430fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers biased_begin += offset; 855d76c435082332ef79a22962386fa92a0870e378Ian Rogers } 86ef7d42fca18c16fbaf103822ad16f23246e2905dIan Rogers CHECK_EQ(reinterpret_cast<uintptr_t>(biased_begin) & 0xff, kCardDirty); 8730fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers return new CardTable(mem_map.release(), biased_begin, offset); 885d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 895d76c435082332ef79a22962386fa92a0870e378Ian Rogers 9013735955f39b3b304c37d2b2840663c131262c18Ian RogersCardTable::CardTable(MemMap* mem_map, uint8_t* biased_begin, size_t offset) 91a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes : mem_map_(mem_map), biased_begin_(biased_begin), offset_(offset) { 92a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes} 93a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes 943481ba2c4e4f3aa80d8c6d50a9f85dacb56b508bVladimir MarkoCardTable::~CardTable() { 953481ba2c4e4f3aa80d8c6d50a9f85dacb56b508bVladimir Marko // Destroys MemMap via std::unique_ptr<>. 963481ba2c4e4f3aa80d8c6d50a9f85dacb56b508bVladimir Marko} 973481ba2c4e4f3aa80d8c6d50a9f85dacb56b508bVladimir Marko 981d54e73444e017d3a65234e0f193846f3e27472bIan Rogersvoid CardTable::ClearSpaceCards(space::ContinuousSpace* space) { 99262e5ffa1d4b23f23af3dea762a71a0af4bfd4a9Mathieu Chartier // TODO: clear just the range of the table that has been modified 10013735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* card_start = CardFromAddr(space->Begin()); 10113735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* card_end = CardFromAddr(space->End()); // Make sure to round up. 1027469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier memset(reinterpret_cast<void*>(card_start), kCardClean, card_end - card_start); 103262e5ffa1d4b23f23af3dea762a71a0af4bfd4a9Mathieu Chartier} 104262e5ffa1d4b23f23af3dea762a71a0af4bfd4a9Mathieu Chartier 1055d76c435082332ef79a22962386fa92a0870e378Ian Rogersvoid CardTable::ClearCardTable() { 106575e78c41ece0dec969d31f46be563d4eb7ae43bAndreas Gampe static_assert(kCardClean == 0, "kCardClean must be 0"); 107c5f17732d8144491c642776b6b48c85dfadf4b52Ian Rogers mem_map_->MadviseDontNeedAndZero(); 1085d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 1095d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1104add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Livoid CardTable::ClearCardRange(uint8_t* start, uint8_t* end) { 1114add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li if (!kMadviseZeroes) { 1124add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li memset(start, 0, end - start); 1134add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li return; 1144add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li } 1154add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li CHECK_ALIGNED(reinterpret_cast<uintptr_t>(start), kCardSize); 1164add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li CHECK_ALIGNED(reinterpret_cast<uintptr_t>(end), kCardSize); 1174add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li static_assert(kCardClean == 0, "kCardClean must be 0"); 1184add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li uint8_t* start_card = CardFromAddr(start); 1194add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li uint8_t* end_card = CardFromAddr(end); 1204add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li uint8_t* round_start = AlignUp(start_card, kPageSize); 1214add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li uint8_t* round_end = AlignDown(end_card, kPageSize); 1224add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li if (round_start < round_end) { 1234add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li madvise(round_start, round_end - round_start, MADV_DONTNEED); 1244add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li } 1254add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li // Handle unaligned regions at start / end. 1264add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li memset(start_card, 0, std::min(round_start, end_card) - start_card); 1274add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li memset(std::max(round_end, start_card), 0, end_card - std::max(round_end, start_card)); 1284add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li} 1294add3b4fa38ec42bb3c71d01cf70bce8e9a9fb4eLei Li 1307469ebf3888b8037421cb6834f37f946646265ecMathieu Chartierbool CardTable::AddrIsInCardTable(const void* addr) const { 1317469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier return IsValidCard(biased_begin_ + ((uintptr_t)addr >> kCardShift)); 1327469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier} 1337469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier 13413735955f39b3b304c37d2b2840663c131262c18Ian Rogersvoid CardTable::CheckAddrIsInCardTable(const uint8_t* addr) const { 13513735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* card_addr = biased_begin_ + ((uintptr_t)addr >> kCardShift); 13613735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* begin = mem_map_->Begin() + offset_; 13713735955f39b3b304c37d2b2840663c131262c18Ian Rogers uint8_t* end = mem_map_->End(); 1387469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier CHECK(AddrIsInCardTable(addr)) 1397469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << "Card table " << this 1407469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " begin: " << reinterpret_cast<void*>(begin) 1417469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " end: " << reinterpret_cast<void*>(end) 1427469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " card_addr: " << reinterpret_cast<void*>(card_addr) 1437469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " heap begin: " << AddrFromCard(begin) 1447469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " heap end: " << AddrFromCard(end) 1457469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " addr: " << reinterpret_cast<const void*>(addr); 1465d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 1475d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1485d76c435082332ef79a22962386fa92a0870e378Ian Rogersvoid CardTable::VerifyCardTable() { 1495d76c435082332ef79a22962386fa92a0870e378Ian Rogers UNIMPLEMENTED(WARNING) << "Card table verification"; 1505d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 1515d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1521d54e73444e017d3a65234e0f193846f3e27472bIan Rogers} // namespace accounting 1531d54e73444e017d3a65234e0f193846f3e27472bIan Rogers} // namespace gc 1545d76c435082332ef79a22962386fa92a0870e378Ian Rogers} // namespace art 155