card_table.cc revision ef7d42fca18c16fbaf103822ad16f23246e2905d
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" 24b3bd5f07884f5a1f2b84224363b1372d7c28d447Elliott Hughes#include "runtime.h" 25f0605a0da70a495521e466c98255d469915a1f00Elliott Hughes#include "utils.h" 265d76c435082332ef79a22962386fa92a0870e378Ian Rogers 275d76c435082332ef79a22962386fa92a0870e378Ian Rogersnamespace art { 281d54e73444e017d3a65234e0f193846f3e27472bIan Rogersnamespace gc { 291d54e73444e017d3a65234e0f193846f3e27472bIan Rogersnamespace accounting { 301d54e73444e017d3a65234e0f193846f3e27472bIan Rogers 315d76c435082332ef79a22962386fa92a0870e378Ian Rogers/* 325d76c435082332ef79a22962386fa92a0870e378Ian Rogers * Maintain a card table from the write barrier. All writes of 335d76c435082332ef79a22962386fa92a0870e378Ian Rogers * non-NULL values to heap addresses should go through an entry in 345d76c435082332ef79a22962386fa92a0870e378Ian Rogers * WriteBarrier, and from there to here. 355d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 365d76c435082332ef79a22962386fa92a0870e378Ian Rogers * The heap is divided into "cards" of GC_CARD_SIZE bytes, as 375d76c435082332ef79a22962386fa92a0870e378Ian Rogers * determined by GC_CARD_SHIFT. The card table contains one byte of 385d76c435082332ef79a22962386fa92a0870e378Ian Rogers * data per card, to be used by the GC. The value of the byte will be 395d76c435082332ef79a22962386fa92a0870e378Ian Rogers * one of GC_CARD_CLEAN or GC_CARD_DIRTY. 405d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 415d76c435082332ef79a22962386fa92a0870e378Ian Rogers * After any store of a non-NULL object pointer into a heap object, 425d76c435082332ef79a22962386fa92a0870e378Ian Rogers * code is obliged to mark the card dirty. The setters in 435d76c435082332ef79a22962386fa92a0870e378Ian Rogers * object.h [such as SetFieldObject] do this for you. The 445d76c435082332ef79a22962386fa92a0870e378Ian Rogers * compiler also contains code to mark cards as dirty. 455d76c435082332ef79a22962386fa92a0870e378Ian Rogers * 465d76c435082332ef79a22962386fa92a0870e378Ian Rogers * The card table's base [the "biased card table"] gets set to a 475d76c435082332ef79a22962386fa92a0870e378Ian Rogers * rather strange value. In order to keep the JIT from having to 485d76c435082332ef79a22962386fa92a0870e378Ian Rogers * fabricate or load GC_DIRTY_CARD to store into the card table, 495d76c435082332ef79a22962386fa92a0870e378Ian Rogers * biased base is within the mmap allocation at a point where its low 5030fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers * byte is equal to GC_DIRTY_CARD. See CardTable::Create for details. 515d76c435082332ef79a22962386fa92a0870e378Ian Rogers */ 525d76c435082332ef79a22962386fa92a0870e378Ian Rogers 5330fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian RogersCardTable* CardTable::Create(const byte* heap_begin, size_t heap_capacity) { 545d76c435082332ef79a22962386fa92a0870e378Ian Rogers /* Set up the card table */ 557469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier size_t capacity = heap_capacity / kCardSize; 565d76c435082332ef79a22962386fa92a0870e378Ian Rogers /* Allocate an extra 256 bytes to allow fixed low-byte of base */ 578d31bbd3d6536de12bc20e3d29cfe03fe848f9daIan Rogers std::string error_msg; 58a40307e8562c20d9b9ce46e773864d07d95512a1Ian Rogers UniquePtr<MemMap> mem_map(MemMap::MapAnonymous("card table", NULL, 598d31bbd3d6536de12bc20e3d29cfe03fe848f9daIan Rogers capacity + 256, PROT_READ | PROT_WRITE, 60ef7d42fca18c16fbaf103822ad16f23246e2905dIan Rogers false, &error_msg)); 618d31bbd3d6536de12bc20e3d29cfe03fe848f9daIan Rogers CHECK(mem_map.get() != NULL) << "couldn't allocate card table: " << error_msg; 6230fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // All zeros is the correct initial value; all clean. Anonymous mmaps are initialized to zero, we 6330fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // don't clear the card table to avoid unnecessary pages being allocated 647469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier COMPILE_ASSERT(kCardClean == 0, card_clean_must_be_0); 6530fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers 6630fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers byte* cardtable_begin = mem_map->Begin(); 6730fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers CHECK(cardtable_begin != NULL); 6830fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers 6930fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // We allocated up to a bytes worth of extra space to allow biased_begin's byte value to equal 7030fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers // GC_CARD_DIRTY, compute a offset value to make this the case 7130fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers size_t offset = 0; 72398f64b5805246765b699839b439e18c0dfbf2eeElliott Hughes byte* biased_begin = reinterpret_cast<byte*>(reinterpret_cast<uintptr_t>(cardtable_begin) - 737469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier (reinterpret_cast<uintptr_t>(heap_begin) >> kCardShift)); 747469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier if (((uintptr_t)biased_begin & 0xff) != kCardDirty) { 75ef7d42fca18c16fbaf103822ad16f23246e2905dIan Rogers int delta = kCardDirty - (reinterpret_cast<uintptr_t>(biased_begin) & 0xff); 7630fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers offset = delta + (delta < 0 ? 0x100 : 0); 7730fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers biased_begin += offset; 785d76c435082332ef79a22962386fa92a0870e378Ian Rogers } 79ef7d42fca18c16fbaf103822ad16f23246e2905dIan Rogers CHECK_EQ(reinterpret_cast<uintptr_t>(biased_begin) & 0xff, kCardDirty); 8030fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers 8130fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogers return new CardTable(mem_map.release(), biased_begin, offset); 825d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 835d76c435082332ef79a22962386fa92a0870e378Ian Rogers 84a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott HughesCardTable::CardTable(MemMap* mem_map, byte* biased_begin, size_t offset) 85a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes : mem_map_(mem_map), biased_begin_(biased_begin), offset_(offset) { 86a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes byte* __attribute__((unused)) begin = mem_map_->Begin() + offset_; 87a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes byte* __attribute__((unused)) end = mem_map_->End(); 88a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes} 89a168c83a1d247094e9efb1244b0f73a5f1e1ed97Elliott Hughes 901d54e73444e017d3a65234e0f193846f3e27472bIan Rogersvoid CardTable::ClearSpaceCards(space::ContinuousSpace* space) { 91262e5ffa1d4b23f23af3dea762a71a0af4bfd4a9Mathieu Chartier // TODO: clear just the range of the table that has been modified 92cc236d74772dda5a4161d9bc5f497fd3d956eb87Mathieu Chartier byte* card_start = CardFromAddr(space->Begin()); 937934ac288acfb2552bb0b06ec1f61e5820d924a4Brian Carlstrom byte* card_end = CardFromAddr(space->End()); // Make sure to round up. 947469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier memset(reinterpret_cast<void*>(card_start), kCardClean, card_end - card_start); 95262e5ffa1d4b23f23af3dea762a71a0af4bfd4a9Mathieu Chartier} 96262e5ffa1d4b23f23af3dea762a71a0af4bfd4a9Mathieu Chartier 975d76c435082332ef79a22962386fa92a0870e378Ian Rogersvoid CardTable::ClearCardTable() { 98c528dba35b5faece51ca658fc008b688f8b690adMathieu Chartier COMPILE_ASSERT(kCardClean == 0, clean_card_must_be_0); 99c528dba35b5faece51ca658fc008b688f8b690adMathieu Chartier madvise(mem_map_->Begin(), mem_map_->Size(), MADV_DONTNEED); 1005d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 1015d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1027469ebf3888b8037421cb6834f37f946646265ecMathieu Chartierbool CardTable::AddrIsInCardTable(const void* addr) const { 1037469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier return IsValidCard(biased_begin_ + ((uintptr_t)addr >> kCardShift)); 1047469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier} 1057469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier 10630fab40ee5a07af6b8c3b6b0e9438071695a57f4Ian Rogersvoid CardTable::CheckAddrIsInCardTable(const byte* addr) const { 1077469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier byte* card_addr = biased_begin_ + ((uintptr_t)addr >> kCardShift); 1087469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier byte* begin = mem_map_->Begin() + offset_; 1097469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier byte* end = mem_map_->End(); 1107469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier CHECK(AddrIsInCardTable(addr)) 1117469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << "Card table " << this 1127469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " begin: " << reinterpret_cast<void*>(begin) 1137469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " end: " << reinterpret_cast<void*>(end) 1147469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " card_addr: " << reinterpret_cast<void*>(card_addr) 1157469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " heap begin: " << AddrFromCard(begin) 1167469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " heap end: " << AddrFromCard(end) 1177469ebf3888b8037421cb6834f37f946646265ecMathieu Chartier << " addr: " << reinterpret_cast<const void*>(addr); 1185d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 1195d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1205d76c435082332ef79a22962386fa92a0870e378Ian Rogersvoid CardTable::VerifyCardTable() { 1215d76c435082332ef79a22962386fa92a0870e378Ian Rogers UNIMPLEMENTED(WARNING) << "Card table verification"; 1225d76c435082332ef79a22962386fa92a0870e378Ian Rogers} 1235d76c435082332ef79a22962386fa92a0870e378Ian Rogers 1241d54e73444e017d3a65234e0f193846f3e27472bIan Rogers} // namespace accounting 1251d54e73444e017d3a65234e0f193846f3e27472bIan Rogers} // namespace gc 1265d76c435082332ef79a22962386fa92a0870e378Ian Rogers} // namespace art 127