1 /*
2  * Copyright (C) 2012 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 "large_object_space.h"
18 
19 #include <sys/mman.h>
20 
21 #include <memory>
22 
23 #include <android-base/logging.h>
24 
25 #include "base/macros.h"
26 #include "base/memory_tool.h"
27 #include "base/mutex-inl.h"
28 #include "base/os.h"
29 #include "base/stl_util.h"
30 #include "gc/accounting/heap_bitmap-inl.h"
31 #include "gc/accounting/space_bitmap-inl.h"
32 #include "gc/heap.h"
33 #include "image.h"
34 #include "scoped_thread_state_change-inl.h"
35 #include "space-inl.h"
36 #include "thread-current-inl.h"
37 
38 namespace art {
39 namespace gc {
40 namespace space {
41 
42 class MemoryToolLargeObjectMapSpace final : public LargeObjectMapSpace {
43  public:
MemoryToolLargeObjectMapSpace(const std::string & name)44   explicit MemoryToolLargeObjectMapSpace(const std::string& name) : LargeObjectMapSpace(name) {
45   }
46 
~MemoryToolLargeObjectMapSpace()47   ~MemoryToolLargeObjectMapSpace() override {
48     // Historical note: We were deleting large objects to keep Valgrind happy if there were
49     // any large objects such as Dex cache arrays which aren't freed since they are held live
50     // by the class linker.
51   }
52 
Alloc(Thread * self,size_t num_bytes,size_t * bytes_allocated,size_t * usable_size,size_t * bytes_tl_bulk_allocated)53   mirror::Object* Alloc(Thread* self, size_t num_bytes, size_t* bytes_allocated,
54                         size_t* usable_size, size_t* bytes_tl_bulk_allocated)
55       override {
56     mirror::Object* obj =
57         LargeObjectMapSpace::Alloc(self, num_bytes + kMemoryToolRedZoneBytes * 2, bytes_allocated,
58                                    usable_size, bytes_tl_bulk_allocated);
59     mirror::Object* object_without_rdz = reinterpret_cast<mirror::Object*>(
60         reinterpret_cast<uintptr_t>(obj) + kMemoryToolRedZoneBytes);
61     MEMORY_TOOL_MAKE_NOACCESS(reinterpret_cast<void*>(obj), kMemoryToolRedZoneBytes);
62     MEMORY_TOOL_MAKE_NOACCESS(
63         reinterpret_cast<uint8_t*>(object_without_rdz) + num_bytes,
64         kMemoryToolRedZoneBytes);
65     if (usable_size != nullptr) {
66       *usable_size = num_bytes;  // Since we have redzones, shrink the usable size.
67     }
68     return object_without_rdz;
69   }
70 
AllocationSize(mirror::Object * obj,size_t * usable_size)71   size_t AllocationSize(mirror::Object* obj, size_t* usable_size) override {
72     return LargeObjectMapSpace::AllocationSize(ObjectWithRedzone(obj), usable_size);
73   }
74 
IsZygoteLargeObject(Thread * self,mirror::Object * obj) const75   bool IsZygoteLargeObject(Thread* self, mirror::Object* obj) const override {
76     return LargeObjectMapSpace::IsZygoteLargeObject(self, ObjectWithRedzone(obj));
77   }
78 
Free(Thread * self,mirror::Object * obj)79   size_t Free(Thread* self, mirror::Object* obj) override {
80     mirror::Object* object_with_rdz = ObjectWithRedzone(obj);
81     MEMORY_TOOL_MAKE_UNDEFINED(object_with_rdz, AllocationSize(obj, nullptr));
82     return LargeObjectMapSpace::Free(self, object_with_rdz);
83   }
84 
Contains(const mirror::Object * obj) const85   bool Contains(const mirror::Object* obj) const override {
86     return LargeObjectMapSpace::Contains(ObjectWithRedzone(obj));
87   }
88 
89  private:
ObjectWithRedzone(const mirror::Object * obj)90   static const mirror::Object* ObjectWithRedzone(const mirror::Object* obj) {
91     return reinterpret_cast<const mirror::Object*>(
92         reinterpret_cast<uintptr_t>(obj) - kMemoryToolRedZoneBytes);
93   }
94 
ObjectWithRedzone(mirror::Object * obj)95   static mirror::Object* ObjectWithRedzone(mirror::Object* obj) {
96     return reinterpret_cast<mirror::Object*>(
97         reinterpret_cast<uintptr_t>(obj) - kMemoryToolRedZoneBytes);
98   }
99 
100   static constexpr size_t kMemoryToolRedZoneBytes = kPageSize;
101 };
102 
SwapBitmaps()103 void LargeObjectSpace::SwapBitmaps() {
104   live_bitmap_.swap(mark_bitmap_);
105   // Swap names to get more descriptive diagnostics.
106   std::string temp_name = live_bitmap_->GetName();
107   live_bitmap_->SetName(mark_bitmap_->GetName());
108   mark_bitmap_->SetName(temp_name);
109 }
110 
LargeObjectSpace(const std::string & name,uint8_t * begin,uint8_t * end,const char * lock_name)111 LargeObjectSpace::LargeObjectSpace(const std::string& name, uint8_t* begin, uint8_t* end,
112                                    const char* lock_name)
113     : DiscontinuousSpace(name, kGcRetentionPolicyAlwaysCollect),
114       lock_(lock_name, kAllocSpaceLock),
115       num_bytes_allocated_(0), num_objects_allocated_(0), total_bytes_allocated_(0),
116       total_objects_allocated_(0), begin_(begin), end_(end) {
117 }
118 
119 
CopyLiveToMarked()120 void LargeObjectSpace::CopyLiveToMarked() {
121   mark_bitmap_->CopyFrom(live_bitmap_.get());
122 }
123 
LargeObjectMapSpace(const std::string & name)124 LargeObjectMapSpace::LargeObjectMapSpace(const std::string& name)
125     : LargeObjectSpace(name, nullptr, nullptr, "large object map space lock") {}
126 
Create(const std::string & name)127 LargeObjectMapSpace* LargeObjectMapSpace::Create(const std::string& name) {
128   if (Runtime::Current()->IsRunningOnMemoryTool()) {
129     return new MemoryToolLargeObjectMapSpace(name);
130   } else {
131     return new LargeObjectMapSpace(name);
132   }
133 }
134 
Alloc(Thread * self,size_t num_bytes,size_t * bytes_allocated,size_t * usable_size,size_t * bytes_tl_bulk_allocated)135 mirror::Object* LargeObjectMapSpace::Alloc(Thread* self, size_t num_bytes,
136                                            size_t* bytes_allocated, size_t* usable_size,
137                                            size_t* bytes_tl_bulk_allocated) {
138   std::string error_msg;
139   MemMap mem_map = MemMap::MapAnonymous("large object space allocation",
140                                         num_bytes,
141                                         PROT_READ | PROT_WRITE,
142                                         /*low_4gb=*/ true,
143                                         &error_msg);
144   if (UNLIKELY(!mem_map.IsValid())) {
145     LOG(WARNING) << "Large object allocation failed: " << error_msg;
146     return nullptr;
147   }
148   mirror::Object* const obj = reinterpret_cast<mirror::Object*>(mem_map.Begin());
149   const size_t allocation_size = mem_map.BaseSize();
150   MutexLock mu(self, lock_);
151   large_objects_.Put(obj, LargeObject {std::move(mem_map), false /* not zygote */});
152   DCHECK(bytes_allocated != nullptr);
153 
154   if (begin_ == nullptr || begin_ > reinterpret_cast<uint8_t*>(obj)) {
155     begin_ = reinterpret_cast<uint8_t*>(obj);
156   }
157   end_ = std::max(end_, reinterpret_cast<uint8_t*>(obj) + allocation_size);
158 
159   *bytes_allocated = allocation_size;
160   if (usable_size != nullptr) {
161     *usable_size = allocation_size;
162   }
163   DCHECK(bytes_tl_bulk_allocated != nullptr);
164   *bytes_tl_bulk_allocated = allocation_size;
165   num_bytes_allocated_ += allocation_size;
166   total_bytes_allocated_ += allocation_size;
167   ++num_objects_allocated_;
168   ++total_objects_allocated_;
169   return obj;
170 }
171 
IsZygoteLargeObject(Thread * self,mirror::Object * obj) const172 bool LargeObjectMapSpace::IsZygoteLargeObject(Thread* self, mirror::Object* obj) const {
173   MutexLock mu(self, lock_);
174   auto it = large_objects_.find(obj);
175   CHECK(it != large_objects_.end());
176   return it->second.is_zygote;
177 }
178 
SetAllLargeObjectsAsZygoteObjects(Thread * self)179 void LargeObjectMapSpace::SetAllLargeObjectsAsZygoteObjects(Thread* self) {
180   MutexLock mu(self, lock_);
181   for (auto& pair : large_objects_) {
182     pair.second.is_zygote = true;
183   }
184 }
185 
Free(Thread * self,mirror::Object * ptr)186 size_t LargeObjectMapSpace::Free(Thread* self, mirror::Object* ptr) {
187   MutexLock mu(self, lock_);
188   auto it = large_objects_.find(ptr);
189   if (UNLIKELY(it == large_objects_.end())) {
190     ScopedObjectAccess soa(self);
191     Runtime::Current()->GetHeap()->DumpSpaces(LOG_STREAM(FATAL_WITHOUT_ABORT));
192     LOG(FATAL) << "Attempted to free large object " << ptr << " which was not live";
193   }
194   const size_t map_size = it->second.mem_map.BaseSize();
195   DCHECK_GE(num_bytes_allocated_, map_size);
196   size_t allocation_size = map_size;
197   num_bytes_allocated_ -= allocation_size;
198   --num_objects_allocated_;
199   large_objects_.erase(it);
200   return allocation_size;
201 }
202 
AllocationSize(mirror::Object * obj,size_t * usable_size)203 size_t LargeObjectMapSpace::AllocationSize(mirror::Object* obj, size_t* usable_size) {
204   MutexLock mu(Thread::Current(), lock_);
205   auto it = large_objects_.find(obj);
206   CHECK(it != large_objects_.end()) << "Attempted to get size of a large object which is not live";
207   size_t alloc_size = it->second.mem_map.BaseSize();
208   if (usable_size != nullptr) {
209     *usable_size = alloc_size;
210   }
211   return alloc_size;
212 }
213 
FreeList(Thread * self,size_t num_ptrs,mirror::Object ** ptrs)214 size_t LargeObjectSpace::FreeList(Thread* self, size_t num_ptrs, mirror::Object** ptrs) {
215   size_t total = 0;
216   for (size_t i = 0; i < num_ptrs; ++i) {
217     if (kDebugSpaces) {
218       CHECK(Contains(ptrs[i]));
219     }
220     total += Free(self, ptrs[i]);
221   }
222   return total;
223 }
224 
Walk(DlMallocSpace::WalkCallback callback,void * arg)225 void LargeObjectMapSpace::Walk(DlMallocSpace::WalkCallback callback, void* arg) {
226   MutexLock mu(Thread::Current(), lock_);
227   for (auto& pair : large_objects_) {
228     MemMap* mem_map = &pair.second.mem_map;
229     callback(mem_map->Begin(), mem_map->End(), mem_map->Size(), arg);
230     callback(nullptr, nullptr, 0, arg);
231   }
232 }
233 
ForEachMemMap(std::function<void (const MemMap &)> func) const234 void LargeObjectMapSpace::ForEachMemMap(std::function<void(const MemMap&)> func) const {
235   MutexLock mu(Thread::Current(), lock_);
236   for (auto& pair : large_objects_) {
237     func(pair.second.mem_map);
238   }
239 }
240 
Contains(const mirror::Object * obj) const241 bool LargeObjectMapSpace::Contains(const mirror::Object* obj) const {
242   Thread* self = Thread::Current();
243   if (lock_.IsExclusiveHeld(self)) {
244     // We hold lock_ so do the check.
245     return large_objects_.find(const_cast<mirror::Object*>(obj)) != large_objects_.end();
246   } else {
247     MutexLock mu(self, lock_);
248     return large_objects_.find(const_cast<mirror::Object*>(obj)) != large_objects_.end();
249   }
250 }
251 
252 // Keeps track of allocation sizes + whether or not the previous allocation is free.
253 // Used to coalesce free blocks and find the best fit block for an allocation for best fit object
254 // allocation. Each allocation has an AllocationInfo which contains the size of the previous free
255 // block preceding it. Implemented in such a way that we can also find the iterator for any
256 // allocation info pointer.
257 class AllocationInfo {
258  public:
AllocationInfo()259   AllocationInfo() : prev_free_(0), alloc_size_(0) {
260   }
261   // Return the number of pages that the allocation info covers.
AlignSize() const262   size_t AlignSize() const {
263     return alloc_size_ & kFlagsMask;
264   }
265   // Returns the allocation size in bytes.
ByteSize() const266   size_t ByteSize() const {
267     return AlignSize() * FreeListSpace::kAlignment;
268   }
269   // Updates the allocation size and whether or not it is free.
SetByteSize(size_t size,bool free)270   void SetByteSize(size_t size, bool free) {
271     DCHECK_EQ(size & ~kFlagsMask, 0u);
272     DCHECK_ALIGNED(size, FreeListSpace::kAlignment);
273     alloc_size_ = (size / FreeListSpace::kAlignment) | (free ? kFlagFree : 0u);
274   }
275   // Returns true if the block is free.
IsFree() const276   bool IsFree() const {
277     return (alloc_size_ & kFlagFree) != 0;
278   }
279   // Return true if the large object is a zygote object.
IsZygoteObject() const280   bool IsZygoteObject() const {
281     return (alloc_size_ & kFlagZygote) != 0;
282   }
283   // Change the object to be a zygote object.
SetZygoteObject()284   void SetZygoteObject() {
285     alloc_size_ |= kFlagZygote;
286   }
287   // Return true if this is a zygote large object.
288   // Finds and returns the next non free allocation info after ourself.
GetNextInfo()289   AllocationInfo* GetNextInfo() {
290     return this + AlignSize();
291   }
GetNextInfo() const292   const AllocationInfo* GetNextInfo() const {
293     return this + AlignSize();
294   }
295   // Returns the previous free allocation info by using the prev_free_ member to figure out
296   // where it is. This is only used for coalescing so we only need to be able to do it if the
297   // previous allocation info is free.
GetPrevFreeInfo()298   AllocationInfo* GetPrevFreeInfo() {
299     DCHECK_NE(prev_free_, 0U);
300     return this - prev_free_;
301   }
302   // Returns the address of the object associated with this allocation info.
GetObjectAddress()303   mirror::Object* GetObjectAddress() {
304     return reinterpret_cast<mirror::Object*>(reinterpret_cast<uintptr_t>(this) + sizeof(*this));
305   }
306   // Return how many kAlignment units there are before the free block.
GetPrevFree() const307   size_t GetPrevFree() const {
308     return prev_free_;
309   }
310   // Returns how many free bytes there is before the block.
GetPrevFreeBytes() const311   size_t GetPrevFreeBytes() const {
312     return GetPrevFree() * FreeListSpace::kAlignment;
313   }
314   // Update the size of the free block prior to the allocation.
SetPrevFreeBytes(size_t bytes)315   void SetPrevFreeBytes(size_t bytes) {
316     DCHECK_ALIGNED(bytes, FreeListSpace::kAlignment);
317     prev_free_ = bytes / FreeListSpace::kAlignment;
318   }
319 
320  private:
321   static constexpr uint32_t kFlagFree = 0x80000000;  // If block is free.
322   static constexpr uint32_t kFlagZygote = 0x40000000;  // If the large object is a zygote object.
323   static constexpr uint32_t kFlagsMask = ~(kFlagFree | kFlagZygote);  // Combined flags for masking.
324   // Contains the size of the previous free block with kAlignment as the unit. If 0 then the
325   // allocation before us is not free.
326   // These variables are undefined in the middle of allocations / free blocks.
327   uint32_t prev_free_;
328   // Allocation size of this object in kAlignment as the unit.
329   uint32_t alloc_size_;
330 };
331 
GetSlotIndexForAllocationInfo(const AllocationInfo * info) const332 size_t FreeListSpace::GetSlotIndexForAllocationInfo(const AllocationInfo* info) const {
333   DCHECK_GE(info, allocation_info_);
334   DCHECK_LT(info, reinterpret_cast<AllocationInfo*>(allocation_info_map_.End()));
335   return info - allocation_info_;
336 }
337 
GetAllocationInfoForAddress(uintptr_t address)338 AllocationInfo* FreeListSpace::GetAllocationInfoForAddress(uintptr_t address) {
339   return &allocation_info_[GetSlotIndexForAddress(address)];
340 }
341 
GetAllocationInfoForAddress(uintptr_t address) const342 const AllocationInfo* FreeListSpace::GetAllocationInfoForAddress(uintptr_t address) const {
343   return &allocation_info_[GetSlotIndexForAddress(address)];
344 }
345 
operator ()(const AllocationInfo * a,const AllocationInfo * b) const346 inline bool FreeListSpace::SortByPrevFree::operator()(const AllocationInfo* a,
347                                                       const AllocationInfo* b) const {
348   if (a->GetPrevFree() < b->GetPrevFree()) return true;
349   if (a->GetPrevFree() > b->GetPrevFree()) return false;
350   if (a->AlignSize() < b->AlignSize()) return true;
351   if (a->AlignSize() > b->AlignSize()) return false;
352   return reinterpret_cast<uintptr_t>(a) < reinterpret_cast<uintptr_t>(b);
353 }
354 
Create(const std::string & name,size_t size)355 FreeListSpace* FreeListSpace::Create(const std::string& name, size_t size) {
356   CHECK_EQ(size % kAlignment, 0U);
357   std::string error_msg;
358   MemMap mem_map = MemMap::MapAnonymous(name.c_str(),
359                                         size,
360                                         PROT_READ | PROT_WRITE,
361                                         /*low_4gb=*/ true,
362                                         &error_msg);
363   CHECK(mem_map.IsValid()) << "Failed to allocate large object space mem map: " << error_msg;
364   return new FreeListSpace(name, std::move(mem_map), mem_map.Begin(), mem_map.End());
365 }
366 
FreeListSpace(const std::string & name,MemMap && mem_map,uint8_t * begin,uint8_t * end)367 FreeListSpace::FreeListSpace(const std::string& name,
368                              MemMap&& mem_map,
369                              uint8_t* begin,
370                              uint8_t* end)
371     : LargeObjectSpace(name, begin, end, "free list space lock"),
372       mem_map_(std::move(mem_map)) {
373   const size_t space_capacity = end - begin;
374   free_end_ = space_capacity;
375   CHECK_ALIGNED(space_capacity, kAlignment);
376   const size_t alloc_info_size = sizeof(AllocationInfo) * (space_capacity / kAlignment);
377   std::string error_msg;
378   allocation_info_map_ =
379       MemMap::MapAnonymous("large object free list space allocation info map",
380                            alloc_info_size,
381                            PROT_READ | PROT_WRITE,
382                            /*low_4gb=*/ false,
383                            &error_msg);
384   CHECK(allocation_info_map_.IsValid()) << "Failed to allocate allocation info map" << error_msg;
385   allocation_info_ = reinterpret_cast<AllocationInfo*>(allocation_info_map_.Begin());
386 }
387 
~FreeListSpace()388 FreeListSpace::~FreeListSpace() {}
389 
Walk(DlMallocSpace::WalkCallback callback,void * arg)390 void FreeListSpace::Walk(DlMallocSpace::WalkCallback callback, void* arg) {
391   MutexLock mu(Thread::Current(), lock_);
392   const uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
393   AllocationInfo* cur_info = &allocation_info_[0];
394   const AllocationInfo* end_info = GetAllocationInfoForAddress(free_end_start);
395   while (cur_info < end_info) {
396     if (!cur_info->IsFree()) {
397       size_t alloc_size = cur_info->ByteSize();
398       uint8_t* byte_start = reinterpret_cast<uint8_t*>(GetAddressForAllocationInfo(cur_info));
399       uint8_t* byte_end = byte_start + alloc_size;
400       callback(byte_start, byte_end, alloc_size, arg);
401       callback(nullptr, nullptr, 0, arg);
402     }
403     cur_info = cur_info->GetNextInfo();
404   }
405   CHECK_EQ(cur_info, end_info);
406 }
407 
ForEachMemMap(std::function<void (const MemMap &)> func) const408 void FreeListSpace::ForEachMemMap(std::function<void(const MemMap&)> func) const {
409   MutexLock mu(Thread::Current(), lock_);
410   func(allocation_info_map_);
411   func(mem_map_);
412 }
413 
RemoveFreePrev(AllocationInfo * info)414 void FreeListSpace::RemoveFreePrev(AllocationInfo* info) {
415   CHECK_GT(info->GetPrevFree(), 0U);
416   auto it = free_blocks_.lower_bound(info);
417   CHECK(it != free_blocks_.end());
418   CHECK_EQ(*it, info);
419   free_blocks_.erase(it);
420 }
421 
Free(Thread * self,mirror::Object * obj)422 size_t FreeListSpace::Free(Thread* self, mirror::Object* obj) {
423   MutexLock mu(self, lock_);
424   DCHECK(Contains(obj)) << reinterpret_cast<void*>(Begin()) << " " << obj << " "
425                         << reinterpret_cast<void*>(End());
426   DCHECK_ALIGNED(obj, kAlignment);
427   AllocationInfo* info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(obj));
428   DCHECK(!info->IsFree());
429   const size_t allocation_size = info->ByteSize();
430   DCHECK_GT(allocation_size, 0U);
431   DCHECK_ALIGNED(allocation_size, kAlignment);
432   info->SetByteSize(allocation_size, true);  // Mark as free.
433   // Look at the next chunk.
434   AllocationInfo* next_info = info->GetNextInfo();
435   // Calculate the start of the end free block.
436   uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
437   size_t prev_free_bytes = info->GetPrevFreeBytes();
438   size_t new_free_size = allocation_size;
439   if (prev_free_bytes != 0) {
440     // Coalesce with previous free chunk.
441     new_free_size += prev_free_bytes;
442     RemoveFreePrev(info);
443     info = info->GetPrevFreeInfo();
444     // The previous allocation info must not be free since we are supposed to always coalesce.
445     DCHECK_EQ(info->GetPrevFreeBytes(), 0U) << "Previous allocation was free";
446   }
447   uintptr_t next_addr = GetAddressForAllocationInfo(next_info);
448   if (next_addr >= free_end_start) {
449     // Easy case, the next chunk is the end free region.
450     CHECK_EQ(next_addr, free_end_start);
451     free_end_ += new_free_size;
452   } else {
453     AllocationInfo* new_free_info;
454     if (next_info->IsFree()) {
455       AllocationInfo* next_next_info = next_info->GetNextInfo();
456       // Next next info can't be free since we always coalesce.
457       DCHECK(!next_next_info->IsFree());
458       DCHECK_ALIGNED(next_next_info->ByteSize(), kAlignment);
459       new_free_info = next_next_info;
460       new_free_size += next_next_info->GetPrevFreeBytes();
461       RemoveFreePrev(next_next_info);
462     } else {
463       new_free_info = next_info;
464     }
465     new_free_info->SetPrevFreeBytes(new_free_size);
466     free_blocks_.insert(new_free_info);
467     info->SetByteSize(new_free_size, true);
468     DCHECK_EQ(info->GetNextInfo(), new_free_info);
469   }
470   --num_objects_allocated_;
471   DCHECK_LE(allocation_size, num_bytes_allocated_);
472   num_bytes_allocated_ -= allocation_size;
473   madvise(obj, allocation_size, MADV_DONTNEED);
474   if (kIsDebugBuild) {
475     // Can't disallow reads since we use them to find next chunks during coalescing.
476     CheckedCall(mprotect, __FUNCTION__, obj, allocation_size, PROT_READ);
477   }
478   return allocation_size;
479 }
480 
AllocationSize(mirror::Object * obj,size_t * usable_size)481 size_t FreeListSpace::AllocationSize(mirror::Object* obj, size_t* usable_size) {
482   DCHECK(Contains(obj));
483   AllocationInfo* info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(obj));
484   DCHECK(!info->IsFree());
485   size_t alloc_size = info->ByteSize();
486   if (usable_size != nullptr) {
487     *usable_size = alloc_size;
488   }
489   return alloc_size;
490 }
491 
Alloc(Thread * self,size_t num_bytes,size_t * bytes_allocated,size_t * usable_size,size_t * bytes_tl_bulk_allocated)492 mirror::Object* FreeListSpace::Alloc(Thread* self, size_t num_bytes, size_t* bytes_allocated,
493                                      size_t* usable_size, size_t* bytes_tl_bulk_allocated) {
494   MutexLock mu(self, lock_);
495   const size_t allocation_size = RoundUp(num_bytes, kAlignment);
496   AllocationInfo temp_info;
497   temp_info.SetPrevFreeBytes(allocation_size);
498   temp_info.SetByteSize(0, false);
499   AllocationInfo* new_info;
500   // Find the smallest chunk at least num_bytes in size.
501   auto it = free_blocks_.lower_bound(&temp_info);
502   if (it != free_blocks_.end()) {
503     AllocationInfo* info = *it;
504     free_blocks_.erase(it);
505     // Fit our object in the previous allocation info free space.
506     new_info = info->GetPrevFreeInfo();
507     // Remove the newly allocated block from the info and update the prev_free_.
508     info->SetPrevFreeBytes(info->GetPrevFreeBytes() - allocation_size);
509     if (info->GetPrevFreeBytes() > 0) {
510       AllocationInfo* new_free = info - info->GetPrevFree();
511       new_free->SetPrevFreeBytes(0);
512       new_free->SetByteSize(info->GetPrevFreeBytes(), true);
513       // If there is remaining space, insert back into the free set.
514       free_blocks_.insert(info);
515     }
516   } else {
517     // Try to steal some memory from the free space at the end of the space.
518     if (LIKELY(free_end_ >= allocation_size)) {
519       // Fit our object at the start of the end free block.
520       new_info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(End()) - free_end_);
521       free_end_ -= allocation_size;
522     } else {
523       return nullptr;
524     }
525   }
526   DCHECK(bytes_allocated != nullptr);
527   *bytes_allocated = allocation_size;
528   if (usable_size != nullptr) {
529     *usable_size = allocation_size;
530   }
531   DCHECK(bytes_tl_bulk_allocated != nullptr);
532   *bytes_tl_bulk_allocated = allocation_size;
533   // Need to do these inside of the lock.
534   ++num_objects_allocated_;
535   ++total_objects_allocated_;
536   num_bytes_allocated_ += allocation_size;
537   total_bytes_allocated_ += allocation_size;
538   mirror::Object* obj = reinterpret_cast<mirror::Object*>(GetAddressForAllocationInfo(new_info));
539   // We always put our object at the start of the free block, there cannot be another free block
540   // before it.
541   if (kIsDebugBuild) {
542     CheckedCall(mprotect, __FUNCTION__, obj, allocation_size, PROT_READ | PROT_WRITE);
543   }
544   new_info->SetPrevFreeBytes(0);
545   new_info->SetByteSize(allocation_size, false);
546   return obj;
547 }
548 
Dump(std::ostream & os) const549 void FreeListSpace::Dump(std::ostream& os) const {
550   MutexLock mu(Thread::Current(), lock_);
551   os << GetName() << " -"
552      << " begin: " << reinterpret_cast<void*>(Begin())
553      << " end: " << reinterpret_cast<void*>(End()) << "\n";
554   uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
555   const AllocationInfo* cur_info =
556       GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(Begin()));
557   const AllocationInfo* end_info = GetAllocationInfoForAddress(free_end_start);
558   while (cur_info < end_info) {
559     size_t size = cur_info->ByteSize();
560     uintptr_t address = GetAddressForAllocationInfo(cur_info);
561     if (cur_info->IsFree()) {
562       os << "Free block at address: " << reinterpret_cast<const void*>(address)
563          << " of length " << size << " bytes\n";
564     } else {
565       os << "Large object at address: " << reinterpret_cast<const void*>(address)
566          << " of length " << size << " bytes\n";
567     }
568     cur_info = cur_info->GetNextInfo();
569   }
570   if (free_end_) {
571     os << "Free block at address: " << reinterpret_cast<const void*>(free_end_start)
572        << " of length " << free_end_ << " bytes\n";
573   }
574 }
575 
IsZygoteLargeObject(Thread * self ATTRIBUTE_UNUSED,mirror::Object * obj) const576 bool FreeListSpace::IsZygoteLargeObject(Thread* self ATTRIBUTE_UNUSED, mirror::Object* obj) const {
577   const AllocationInfo* info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(obj));
578   DCHECK(info != nullptr);
579   return info->IsZygoteObject();
580 }
581 
SetAllLargeObjectsAsZygoteObjects(Thread * self)582 void FreeListSpace::SetAllLargeObjectsAsZygoteObjects(Thread* self) {
583   MutexLock mu(self, lock_);
584   uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
585   for (AllocationInfo* cur_info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(Begin())),
586       *end_info = GetAllocationInfoForAddress(free_end_start); cur_info < end_info;
587       cur_info = cur_info->GetNextInfo()) {
588     if (!cur_info->IsFree()) {
589       cur_info->SetZygoteObject();
590     }
591   }
592 }
593 
SweepCallback(size_t num_ptrs,mirror::Object ** ptrs,void * arg)594 void LargeObjectSpace::SweepCallback(size_t num_ptrs, mirror::Object** ptrs, void* arg) {
595   SweepCallbackContext* context = static_cast<SweepCallbackContext*>(arg);
596   space::LargeObjectSpace* space = context->space->AsLargeObjectSpace();
597   Thread* self = context->self;
598   Locks::heap_bitmap_lock_->AssertExclusiveHeld(self);
599   // If the bitmaps aren't swapped we need to clear the bits since the GC isn't going to re-swap
600   // the bitmaps as an optimization.
601   if (!context->swap_bitmaps) {
602     accounting::LargeObjectBitmap* bitmap = space->GetLiveBitmap();
603     for (size_t i = 0; i < num_ptrs; ++i) {
604       bitmap->Clear(ptrs[i]);
605     }
606   }
607   context->freed.objects += num_ptrs;
608   context->freed.bytes += space->FreeList(self, num_ptrs, ptrs);
609 }
610 
Sweep(bool swap_bitmaps)611 collector::ObjectBytePair LargeObjectSpace::Sweep(bool swap_bitmaps) {
612   if (Begin() >= End()) {
613     return collector::ObjectBytePair(0, 0);
614   }
615   accounting::LargeObjectBitmap* live_bitmap = GetLiveBitmap();
616   accounting::LargeObjectBitmap* mark_bitmap = GetMarkBitmap();
617   if (swap_bitmaps) {
618     std::swap(live_bitmap, mark_bitmap);
619   }
620   AllocSpace::SweepCallbackContext scc(swap_bitmaps, this);
621   std::pair<uint8_t*, uint8_t*> range = GetBeginEndAtomic();
622   accounting::LargeObjectBitmap::SweepWalk(*live_bitmap, *mark_bitmap,
623                                            reinterpret_cast<uintptr_t>(range.first),
624                                            reinterpret_cast<uintptr_t>(range.second),
625                                            SweepCallback,
626                                            &scc);
627   return scc.freed;
628 }
629 
LogFragmentationAllocFailure(std::ostream &,size_t)630 void LargeObjectSpace::LogFragmentationAllocFailure(std::ostream& /*os*/,
631                                                     size_t /*failed_alloc_bytes*/) {
632   UNIMPLEMENTED(FATAL);
633 }
634 
GetBeginEndAtomic() const635 std::pair<uint8_t*, uint8_t*> LargeObjectMapSpace::GetBeginEndAtomic() const {
636   MutexLock mu(Thread::Current(), lock_);
637   return std::make_pair(Begin(), End());
638 }
639 
GetBeginEndAtomic() const640 std::pair<uint8_t*, uint8_t*> FreeListSpace::GetBeginEndAtomic() const {
641   MutexLock mu(Thread::Current(), lock_);
642   return std::make_pair(Begin(), End());
643 }
644 
645 }  // namespace space
646 }  // namespace gc
647 }  // namespace art
648