1 /* 2 * Copyright (C) 2013 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 "malloc_space.h" 18 19 #include "gc/accounting/card_table-inl.h" 20 #include "gc/accounting/space_bitmap-inl.h" 21 #include "gc/heap.h" 22 #include "gc/space/space-inl.h" 23 #include "gc/space/zygote_space.h" 24 #include "mirror/class-inl.h" 25 #include "mirror/object-inl.h" 26 #include "runtime.h" 27 #include "handle_scope-inl.h" 28 #include "thread.h" 29 #include "thread_list.h" 30 #include "utils.h" 31 32 namespace art { 33 namespace gc { 34 namespace space { 35 36 size_t MallocSpace::bitmap_index_ = 0; 37 38 MallocSpace::MallocSpace(const std::string& name, MemMap* mem_map, 39 uint8_t* begin, uint8_t* end, uint8_t* limit, size_t growth_limit, 40 bool create_bitmaps, bool can_move_objects, size_t starting_size, 41 size_t initial_size) 42 : ContinuousMemMapAllocSpace(name, mem_map, begin, end, limit, kGcRetentionPolicyAlwaysCollect), 43 recent_free_pos_(0), lock_("allocation space lock", kAllocSpaceLock), 44 growth_limit_(growth_limit), can_move_objects_(can_move_objects), 45 starting_size_(starting_size), initial_size_(initial_size) { 46 if (create_bitmaps) { 47 size_t bitmap_index = bitmap_index_++; 48 static const uintptr_t kGcCardSize = static_cast<uintptr_t>(accounting::CardTable::kCardSize); 49 CHECK_ALIGNED(reinterpret_cast<uintptr_t>(mem_map->Begin()), kGcCardSize); 50 CHECK_ALIGNED(reinterpret_cast<uintptr_t>(mem_map->End()), kGcCardSize); 51 live_bitmap_.reset(accounting::ContinuousSpaceBitmap::Create( 52 StringPrintf("allocspace %s live-bitmap %d", name.c_str(), static_cast<int>(bitmap_index)), 53 Begin(), NonGrowthLimitCapacity())); 54 CHECK(live_bitmap_.get() != nullptr) << "could not create allocspace live bitmap #" 55 << bitmap_index; 56 mark_bitmap_.reset(accounting::ContinuousSpaceBitmap::Create( 57 StringPrintf("allocspace %s mark-bitmap %d", name.c_str(), static_cast<int>(bitmap_index)), 58 Begin(), NonGrowthLimitCapacity())); 59 CHECK(mark_bitmap_.get() != nullptr) << "could not create allocspace mark bitmap #" 60 << bitmap_index; 61 } 62 for (auto& freed : recent_freed_objects_) { 63 freed.first = nullptr; 64 freed.second = nullptr; 65 } 66 } 67 68 MemMap* MallocSpace::CreateMemMap(const std::string& name, size_t starting_size, size_t* initial_size, 69 size_t* growth_limit, size_t* capacity, uint8_t* requested_begin) { 70 // Sanity check arguments 71 if (starting_size > *initial_size) { 72 *initial_size = starting_size; 73 } 74 if (*initial_size > *growth_limit) { 75 LOG(ERROR) << "Failed to create alloc space (" << name << ") where the initial size (" 76 << PrettySize(*initial_size) << ") is larger than its capacity (" 77 << PrettySize(*growth_limit) << ")"; 78 return nullptr; 79 } 80 if (*growth_limit > *capacity) { 81 LOG(ERROR) << "Failed to create alloc space (" << name << ") where the growth limit capacity (" 82 << PrettySize(*growth_limit) << ") is larger than the capacity (" 83 << PrettySize(*capacity) << ")"; 84 return nullptr; 85 } 86 87 // Page align growth limit and capacity which will be used to manage mmapped storage 88 *growth_limit = RoundUp(*growth_limit, kPageSize); 89 *capacity = RoundUp(*capacity, kPageSize); 90 91 std::string error_msg; 92 MemMap* mem_map = MemMap::MapAnonymous(name.c_str(), requested_begin, *capacity, 93 PROT_READ | PROT_WRITE, true, false, &error_msg); 94 if (mem_map == nullptr) { 95 LOG(ERROR) << "Failed to allocate pages for alloc space (" << name << ") of size " 96 << PrettySize(*capacity) << ": " << error_msg; 97 } 98 return mem_map; 99 } 100 101 mirror::Class* MallocSpace::FindRecentFreedObject(const mirror::Object* obj) { 102 size_t pos = recent_free_pos_; 103 // Start at the most recently freed object and work our way back since there may be duplicates 104 // caused by dlmalloc reusing memory. 105 if (kRecentFreeCount > 0) { 106 for (size_t i = 0; i + 1 < kRecentFreeCount + 1; ++i) { 107 pos = pos != 0 ? pos - 1 : kRecentFreeMask; 108 if (recent_freed_objects_[pos].first == obj) { 109 return recent_freed_objects_[pos].second; 110 } 111 } 112 } 113 return nullptr; 114 } 115 116 void MallocSpace::RegisterRecentFree(mirror::Object* ptr) { 117 // No verification since the object is dead. 118 recent_freed_objects_[recent_free_pos_] = std::make_pair(ptr, ptr->GetClass<kVerifyNone>()); 119 recent_free_pos_ = (recent_free_pos_ + 1) & kRecentFreeMask; 120 } 121 122 void MallocSpace::SetGrowthLimit(size_t growth_limit) { 123 growth_limit = RoundUp(growth_limit, kPageSize); 124 growth_limit_ = growth_limit; 125 if (Size() > growth_limit_) { 126 SetEnd(begin_ + growth_limit); 127 } 128 } 129 130 void* MallocSpace::MoreCore(intptr_t increment) { 131 CheckMoreCoreForPrecondition(); 132 uint8_t* original_end = End(); 133 if (increment != 0) { 134 VLOG(heap) << "MallocSpace::MoreCore " << PrettySize(increment); 135 uint8_t* new_end = original_end + increment; 136 if (increment > 0) { 137 // Should never be asked to increase the allocation beyond the capacity of the space. Enforced 138 // by mspace_set_footprint_limit. 139 CHECK_LE(new_end, Begin() + Capacity()); 140 CHECK_MEMORY_CALL(mprotect, (original_end, increment, PROT_READ | PROT_WRITE), GetName()); 141 } else { 142 // Should never be asked for negative footprint (ie before begin). Zero footprint is ok. 143 CHECK_GE(original_end + increment, Begin()); 144 // Advise we don't need the pages and protect them 145 // TODO: by removing permissions to the pages we may be causing TLB shoot-down which can be 146 // expensive (note the same isn't true for giving permissions to a page as the protected 147 // page shouldn't be in a TLB). We should investigate performance impact of just 148 // removing ignoring the memory protection change here and in Space::CreateAllocSpace. It's 149 // likely just a useful debug feature. 150 size_t size = -increment; 151 CHECK_MEMORY_CALL(madvise, (new_end, size, MADV_DONTNEED), GetName()); 152 CHECK_MEMORY_CALL(mprotect, (new_end, size, PROT_NONE), GetName()); 153 } 154 // Update end_. 155 SetEnd(new_end); 156 } 157 return original_end; 158 } 159 160 ZygoteSpace* MallocSpace::CreateZygoteSpace(const char* alloc_space_name, bool low_memory_mode, 161 MallocSpace** out_malloc_space) { 162 // For RosAlloc, revoke thread local runs before creating a new 163 // alloc space so that we won't mix thread local runs from different 164 // alloc spaces. 165 RevokeAllThreadLocalBuffers(); 166 SetEnd(reinterpret_cast<uint8_t*>(RoundUp(reinterpret_cast<uintptr_t>(End()), kPageSize))); 167 DCHECK_ALIGNED(begin_, accounting::CardTable::kCardSize); 168 DCHECK_ALIGNED(End(), accounting::CardTable::kCardSize); 169 DCHECK_ALIGNED(begin_, kPageSize); 170 DCHECK_ALIGNED(End(), kPageSize); 171 size_t size = RoundUp(Size(), kPageSize); 172 // Trimming the heap should be done by the caller since we may have invalidated the accounting 173 // stored in between objects. 174 // Remaining size is for the new alloc space. 175 const size_t growth_limit = growth_limit_ - size; 176 // Use mem map limit in case error for clear growth limit. 177 const size_t capacity = NonGrowthLimitCapacity() - size; 178 VLOG(heap) << "Begin " << reinterpret_cast<const void*>(begin_) << "\n" 179 << "End " << reinterpret_cast<const void*>(End()) << "\n" 180 << "Size " << size << "\n" 181 << "GrowthLimit " << growth_limit_ << "\n" 182 << "Capacity " << Capacity(); 183 SetGrowthLimit(RoundUp(size, kPageSize)); 184 // FIXME: Do we need reference counted pointers here? 185 // Make the two spaces share the same mark bitmaps since the bitmaps span both of the spaces. 186 VLOG(heap) << "Creating new AllocSpace: "; 187 VLOG(heap) << "Size " << GetMemMap()->Size(); 188 VLOG(heap) << "GrowthLimit " << PrettySize(growth_limit); 189 VLOG(heap) << "Capacity " << PrettySize(capacity); 190 // Remap the tail. 191 std::string error_msg; 192 std::unique_ptr<MemMap> mem_map(GetMemMap()->RemapAtEnd(End(), alloc_space_name, 193 PROT_READ | PROT_WRITE, &error_msg)); 194 CHECK(mem_map.get() != nullptr) << error_msg; 195 void* allocator = CreateAllocator(End(), starting_size_, initial_size_, capacity, 196 low_memory_mode); 197 // Protect memory beyond the initial size. 198 uint8_t* end = mem_map->Begin() + starting_size_; 199 if (capacity > initial_size_) { 200 CHECK_MEMORY_CALL(mprotect, (end, capacity - initial_size_, PROT_NONE), alloc_space_name); 201 } 202 *out_malloc_space = CreateInstance(mem_map.release(), alloc_space_name, allocator, End(), end, 203 limit_, growth_limit, CanMoveObjects()); 204 SetLimit(End()); 205 live_bitmap_->SetHeapLimit(reinterpret_cast<uintptr_t>(End())); 206 CHECK_EQ(live_bitmap_->HeapLimit(), reinterpret_cast<uintptr_t>(End())); 207 mark_bitmap_->SetHeapLimit(reinterpret_cast<uintptr_t>(End())); 208 CHECK_EQ(mark_bitmap_->HeapLimit(), reinterpret_cast<uintptr_t>(End())); 209 210 // Create the actual zygote space. 211 ZygoteSpace* zygote_space = ZygoteSpace::Create("Zygote space", ReleaseMemMap(), 212 live_bitmap_.release(), mark_bitmap_.release()); 213 if (UNLIKELY(zygote_space == nullptr)) { 214 VLOG(heap) << "Failed creating zygote space from space " << GetName(); 215 } else { 216 VLOG(heap) << "zygote space creation done"; 217 } 218 return zygote_space; 219 } 220 221 void MallocSpace::Dump(std::ostream& os) const { 222 os << GetType() 223 << " begin=" << reinterpret_cast<void*>(Begin()) 224 << ",end=" << reinterpret_cast<void*>(End()) 225 << ",limit=" << reinterpret_cast<void*>(Limit()) 226 << ",size=" << PrettySize(Size()) << ",capacity=" << PrettySize(Capacity()) 227 << ",non_growth_limit_capacity=" << PrettySize(NonGrowthLimitCapacity()) 228 << ",name=\"" << GetName() << "\"]"; 229 } 230 231 void MallocSpace::SweepCallback(size_t num_ptrs, mirror::Object** ptrs, void* arg) { 232 SweepCallbackContext* context = static_cast<SweepCallbackContext*>(arg); 233 space::MallocSpace* space = context->space->AsMallocSpace(); 234 Thread* self = context->self; 235 Locks::heap_bitmap_lock_->AssertExclusiveHeld(self); 236 // If the bitmaps aren't swapped we need to clear the bits since the GC isn't going to re-swap 237 // the bitmaps as an optimization. 238 if (!context->swap_bitmaps) { 239 accounting::ContinuousSpaceBitmap* bitmap = space->GetLiveBitmap(); 240 for (size_t i = 0; i < num_ptrs; ++i) { 241 bitmap->Clear(ptrs[i]); 242 } 243 } 244 // Use a bulk free, that merges consecutive objects before freeing or free per object? 245 // Documentation suggests better free performance with merging, but this may be at the expensive 246 // of allocation. 247 context->freed.objects += num_ptrs; 248 context->freed.bytes += space->FreeList(self, num_ptrs, ptrs); 249 } 250 251 void MallocSpace::ClampGrowthLimit() { 252 size_t new_capacity = Capacity(); 253 CHECK_LE(new_capacity, NonGrowthLimitCapacity()); 254 GetLiveBitmap()->SetHeapSize(new_capacity); 255 GetMarkBitmap()->SetHeapSize(new_capacity); 256 if (temp_bitmap_.get() != nullptr) { 257 // If the bitmaps are clamped, then the temp bitmap is actually the mark bitmap. 258 temp_bitmap_->SetHeapSize(new_capacity); 259 } 260 GetMemMap()->SetSize(new_capacity); 261 limit_ = Begin() + new_capacity; 262 } 263 264 } // namespace space 265 } // namespace gc 266 } // namespace art 267
