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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 "mirror/object-readbarrier-inl.h"
34 #include "oat/image.h"
35 #include "scoped_thread_state_change-inl.h"
36 #include "space-inl.h"
37 #include "thread-current-inl.h"
38 
39 namespace art HIDDEN {
40 namespace gc {
41 namespace space {
42 
43 class MemoryToolLargeObjectMapSpace final : public LargeObjectMapSpace {
44  public:
MemoryToolLargeObjectMapSpace(const std::string & name)45   explicit MemoryToolLargeObjectMapSpace(const std::string& name) : LargeObjectMapSpace(name) {
46   }
47 
~MemoryToolLargeObjectMapSpace()48   ~MemoryToolLargeObjectMapSpace() override {
49     // Historical note: We were deleting large objects to keep Valgrind happy if there were
50     // any large objects such as Dex cache arrays which aren't freed since they are held live
51     // by the class linker.
52   }
53 
Alloc(Thread * self,size_t num_bytes,size_t * bytes_allocated,size_t * usable_size,size_t * bytes_tl_bulk_allocated)54   mirror::Object* Alloc(Thread* self, size_t num_bytes, size_t* bytes_allocated,
55                         size_t* usable_size, size_t* bytes_tl_bulk_allocated)
56       override {
57     mirror::Object* obj =
58         LargeObjectMapSpace::Alloc(self, num_bytes + MemoryToolRedZoneBytes() * 2, bytes_allocated,
59                                    usable_size, bytes_tl_bulk_allocated);
60     mirror::Object* object_without_rdz = reinterpret_cast<mirror::Object*>(
61         reinterpret_cast<uintptr_t>(obj) + MemoryToolRedZoneBytes());
62     MEMORY_TOOL_MAKE_NOACCESS(reinterpret_cast<void*>(obj), MemoryToolRedZoneBytes());
63     MEMORY_TOOL_MAKE_NOACCESS(
64         reinterpret_cast<uint8_t*>(object_without_rdz) + num_bytes,
65         MemoryToolRedZoneBytes());
66     if (usable_size != nullptr) {
67       *usable_size = num_bytes;  // Since we have redzones, shrink the usable size.
68     }
69     return object_without_rdz;
70   }
71 
AllocationSize(mirror::Object * obj,size_t * usable_size)72   size_t AllocationSize(mirror::Object* obj, size_t* usable_size) override {
73     return LargeObjectMapSpace::AllocationSize(ObjectWithRedzone(obj), usable_size);
74   }
75 
IsZygoteLargeObject(Thread * self,mirror::Object * obj) const76   bool IsZygoteLargeObject(Thread* self, mirror::Object* obj) const override {
77     return LargeObjectMapSpace::IsZygoteLargeObject(self, ObjectWithRedzone(obj));
78   }
79 
Free(Thread * self,mirror::Object * obj)80   size_t Free(Thread* self, mirror::Object* obj) override {
81     mirror::Object* object_with_rdz = ObjectWithRedzone(obj);
82     MEMORY_TOOL_MAKE_UNDEFINED(object_with_rdz, AllocationSize(obj, nullptr));
83     return LargeObjectMapSpace::Free(self, object_with_rdz);
84   }
85 
Contains(const mirror::Object * obj) const86   bool Contains(const mirror::Object* obj) const override {
87     return LargeObjectMapSpace::Contains(ObjectWithRedzone(obj));
88   }
89 
90  private:
MemoryToolRedZoneBytes()91   static size_t MemoryToolRedZoneBytes() {
92     return gPageSize;
93   }
94 
ObjectWithRedzone(const mirror::Object * obj)95   static const mirror::Object* ObjectWithRedzone(const mirror::Object* obj) {
96     return reinterpret_cast<const mirror::Object*>(
97         reinterpret_cast<uintptr_t>(obj) - MemoryToolRedZoneBytes());
98   }
99 
ObjectWithRedzone(mirror::Object * obj)100   static mirror::Object* ObjectWithRedzone(mirror::Object* obj) {
101     return reinterpret_cast<mirror::Object*>(
102         reinterpret_cast<uintptr_t>(obj) - MemoryToolRedZoneBytes());
103   }
104 };
105 
SwapBitmaps()106 void LargeObjectSpace::SwapBitmaps() {
107   std::swap(live_bitmap_, mark_bitmap_);
108   // Preserve names to get more descriptive diagnostics.
109   std::string temp_name = live_bitmap_.GetName();
110   live_bitmap_.SetName(mark_bitmap_.GetName());
111   mark_bitmap_.SetName(temp_name);
112 }
113 
LargeObjectSpace(const std::string & name,uint8_t * begin,uint8_t * end,const char * lock_name)114 LargeObjectSpace::LargeObjectSpace(const std::string& name, uint8_t* begin, uint8_t* end,
115                                    const char* lock_name)
116     : DiscontinuousSpace(name, kGcRetentionPolicyAlwaysCollect),
117       lock_(lock_name, kAllocSpaceLock),
118       num_bytes_allocated_(0), num_objects_allocated_(0), total_bytes_allocated_(0),
119       total_objects_allocated_(0), begin_(begin), end_(end) {
120 }
121 
122 
CopyLiveToMarked()123 void LargeObjectSpace::CopyLiveToMarked() {
124   mark_bitmap_.CopyFrom(&live_bitmap_);
125 }
126 
LargeObjectMapSpace(const std::string & name)127 LargeObjectMapSpace::LargeObjectMapSpace(const std::string& name)
128     : LargeObjectSpace(name, nullptr, nullptr, "large object map space lock") {}
129 
Create(const std::string & name)130 LargeObjectMapSpace* LargeObjectMapSpace::Create(const std::string& name) {
131   if (Runtime::Current()->IsRunningOnMemoryTool()) {
132     return new MemoryToolLargeObjectMapSpace(name);
133   } else {
134     return new LargeObjectMapSpace(name);
135   }
136 }
137 
Alloc(Thread * self,size_t num_bytes,size_t * bytes_allocated,size_t * usable_size,size_t * bytes_tl_bulk_allocated)138 mirror::Object* LargeObjectMapSpace::Alloc(Thread* self, size_t num_bytes,
139                                            size_t* bytes_allocated, size_t* usable_size,
140                                            size_t* bytes_tl_bulk_allocated) {
141   DCHECK_LE(gPageSize, ObjectAlignment())
142       << "MapAnonymousAligned() should be used if the large-object alignment is larger than the "
143          "runtime page size";
144   std::string error_msg;
145   MemMap mem_map = MemMap::MapAnonymous("large object space allocation",
146                                         num_bytes,
147                                         PROT_READ | PROT_WRITE,
148                                         /*low_4gb=*/true,
149                                         &error_msg);
150   if (UNLIKELY(!mem_map.IsValid())) {
151     LOG(WARNING) << "Large object allocation failed: " << error_msg;
152     return nullptr;
153   }
154   mirror::Object* const obj = reinterpret_cast<mirror::Object*>(mem_map.Begin());
155   const size_t allocation_size = mem_map.BaseSize();
156   MutexLock mu(self, lock_);
157   large_objects_.Put(obj, LargeObject {std::move(mem_map), false /* not zygote */});
158   DCHECK(bytes_allocated != nullptr);
159 
160   if (begin_ == nullptr || begin_ > reinterpret_cast<uint8_t*>(obj)) {
161     begin_ = reinterpret_cast<uint8_t*>(obj);
162   }
163   end_ = std::max(end_, reinterpret_cast<uint8_t*>(obj) + allocation_size);
164 
165   *bytes_allocated = allocation_size;
166   if (usable_size != nullptr) {
167     *usable_size = allocation_size;
168   }
169   DCHECK(bytes_tl_bulk_allocated != nullptr);
170   *bytes_tl_bulk_allocated = allocation_size;
171   num_bytes_allocated_ += allocation_size;
172   total_bytes_allocated_ += allocation_size;
173   ++num_objects_allocated_;
174   ++total_objects_allocated_;
175   return obj;
176 }
177 
IsZygoteLargeObject(Thread * self,mirror::Object * obj) const178 bool LargeObjectMapSpace::IsZygoteLargeObject(Thread* self, mirror::Object* obj) const {
179   MutexLock mu(self, lock_);
180   auto it = large_objects_.find(obj);
181   CHECK(it != large_objects_.end());
182   return it->second.is_zygote;
183 }
184 
SetAllLargeObjectsAsZygoteObjects(Thread * self,bool set_mark_bit)185 void LargeObjectMapSpace::SetAllLargeObjectsAsZygoteObjects(Thread* self, bool set_mark_bit) {
186   MutexLock mu(self, lock_);
187   for (auto& pair : large_objects_) {
188     pair.second.is_zygote = true;
189     if (set_mark_bit) {
190       bool success = pair.first->AtomicSetMarkBit(0, 1);
191       CHECK(success);
192     }
193   }
194 }
195 
Free(Thread * self,mirror::Object * ptr)196 size_t LargeObjectMapSpace::Free(Thread* self, mirror::Object* ptr) {
197   MutexLock mu(self, lock_);
198   auto it = large_objects_.find(ptr);
199   if (UNLIKELY(it == large_objects_.end())) {
200     ScopedObjectAccess soa(self);
201     Runtime::Current()->GetHeap()->DumpSpaces(LOG_STREAM(FATAL_WITHOUT_ABORT));
202     LOG(FATAL) << "Attempted to free large object " << ptr << " which was not live";
203   }
204   const size_t map_size = it->second.mem_map.BaseSize();
205   DCHECK_GE(num_bytes_allocated_, map_size);
206   size_t allocation_size = map_size;
207   num_bytes_allocated_ -= allocation_size;
208   --num_objects_allocated_;
209   large_objects_.erase(it);
210   return allocation_size;
211 }
212 
AllocationSize(mirror::Object * obj,size_t * usable_size)213 size_t LargeObjectMapSpace::AllocationSize(mirror::Object* obj, size_t* usable_size) {
214   MutexLock mu(Thread::Current(), lock_);
215   auto it = large_objects_.find(obj);
216   CHECK(it != large_objects_.end()) << "Attempted to get size of a large object which is not live";
217   size_t alloc_size = it->second.mem_map.BaseSize();
218   if (usable_size != nullptr) {
219     *usable_size = alloc_size;
220   }
221   return alloc_size;
222 }
223 
FreeList(Thread * self,size_t num_ptrs,mirror::Object ** ptrs)224 size_t LargeObjectSpace::FreeList(Thread* self, size_t num_ptrs, mirror::Object** ptrs) {
225   size_t total = 0;
226   for (size_t i = 0; i < num_ptrs; ++i) {
227     if (kDebugSpaces) {
228       CHECK(Contains(ptrs[i]));
229     }
230     total += Free(self, ptrs[i]);
231   }
232   return total;
233 }
234 
Walk(DlMallocSpace::WalkCallback callback,void * arg)235 void LargeObjectMapSpace::Walk(DlMallocSpace::WalkCallback callback, void* arg) {
236   MutexLock mu(Thread::Current(), lock_);
237   for (auto& pair : large_objects_) {
238     MemMap* mem_map = &pair.second.mem_map;
239     callback(mem_map->Begin(), mem_map->End(), mem_map->Size(), arg);
240     callback(nullptr, nullptr, 0, arg);
241   }
242 }
243 
ForEachMemMap(std::function<void (const MemMap &)> func) const244 void LargeObjectMapSpace::ForEachMemMap(std::function<void(const MemMap&)> func) const {
245   MutexLock mu(Thread::Current(), lock_);
246   for (auto& pair : large_objects_) {
247     func(pair.second.mem_map);
248   }
249 }
250 
Contains(const mirror::Object * obj) const251 bool LargeObjectMapSpace::Contains(const mirror::Object* obj) const {
252   Thread* self = Thread::Current();
253   if (lock_.IsExclusiveHeld(self)) {
254     // We hold lock_ so do the check.
255     return large_objects_.find(const_cast<mirror::Object*>(obj)) != large_objects_.end();
256   } else {
257     MutexLock mu(self, lock_);
258     return large_objects_.find(const_cast<mirror::Object*>(obj)) != large_objects_.end();
259   }
260 }
261 
262 // Keeps track of allocation sizes + whether or not the previous allocation is free.
263 // Used to coalesce free blocks and find the best fit block for an allocation for best fit object
264 // allocation. Each allocation has an AllocationInfo which contains the size of the previous free
265 // block preceding it. Implemented in such a way that we can also find the iterator for any
266 // allocation info pointer.
267 class AllocationInfo {
268  public:
AllocationInfo()269   AllocationInfo() : prev_free_(0), alloc_size_(0) {
270   }
271   // Return the number of blocks, of the large-object alignment in size each, that the allocation
272   // info covers.
AlignSize() const273   size_t AlignSize() const {
274     return alloc_size_ & kFlagsMask;
275   }
276   // Returns the allocation size in bytes.
ByteSize() const277   size_t ByteSize() const {
278     return AlignSize() * LargeObjectSpace::ObjectAlignment();
279   }
280   // Updates the allocation size and whether or not it is free.
SetByteSize(size_t size,bool free)281   void SetByteSize(size_t size, bool free) {
282     DCHECK_EQ(size & ~kFlagsMask, 0u);
283     DCHECK_ALIGNED_PARAM(size, LargeObjectSpace::ObjectAlignment());
284     alloc_size_ = (size / LargeObjectSpace::ObjectAlignment()) | (free ? kFlagFree : 0u);
285   }
286   // Returns true if the block is free.
IsFree() const287   bool IsFree() const {
288     return (alloc_size_ & kFlagFree) != 0;
289   }
290   // Return true if the large object is a zygote object.
IsZygoteObject() const291   bool IsZygoteObject() const {
292     return (alloc_size_ & kFlagZygote) != 0;
293   }
294   // Change the object to be a zygote object.
SetZygoteObject()295   void SetZygoteObject() {
296     alloc_size_ |= kFlagZygote;
297   }
298   // Return true if this is a zygote large object.
299   // Finds and returns the next non free allocation info after ourself.
GetNextInfo()300   AllocationInfo* GetNextInfo() {
301     return this + AlignSize();
302   }
GetNextInfo() const303   const AllocationInfo* GetNextInfo() const {
304     return this + AlignSize();
305   }
306   // Returns the previous free allocation info by using the prev_free_ member to figure out
307   // where it is. This is only used for coalescing so we only need to be able to do it if the
308   // previous allocation info is free.
GetPrevFreeInfo()309   AllocationInfo* GetPrevFreeInfo() {
310     DCHECK_NE(prev_free_, 0U);
311     return this - prev_free_;
312   }
313   // Returns the address of the object associated with this allocation info.
GetObjectAddress()314   mirror::Object* GetObjectAddress() {
315     return reinterpret_cast<mirror::Object*>(reinterpret_cast<uintptr_t>(this) + sizeof(*this));
316   }
317   // Return how many units, the large-object alignment value in size,
318   // there are before the free block.
GetPrevFree() const319   size_t GetPrevFree() const {
320     return prev_free_;
321   }
322   // Returns how many free bytes there are before the block.
GetPrevFreeBytes() const323   size_t GetPrevFreeBytes() const {
324     return GetPrevFree() * LargeObjectSpace::ObjectAlignment();
325   }
326   // Update the size of the free block prior to the allocation.
SetPrevFreeBytes(size_t bytes)327   void SetPrevFreeBytes(size_t bytes) {
328     DCHECK_ALIGNED_PARAM(bytes, LargeObjectSpace::ObjectAlignment());
329     prev_free_ = bytes / LargeObjectSpace::ObjectAlignment();
330   }
331 
332  private:
333   static constexpr uint32_t kFlagFree = 0x80000000;  // If block is free.
334   static constexpr uint32_t kFlagZygote = 0x40000000;  // If the large object is a zygote object.
335   static constexpr uint32_t kFlagsMask = ~(kFlagFree | kFlagZygote);  // Combined flags for masking.
336   // Contains the size of the previous free block with the large-object alignment value as the
337   // unit. If 0 then the allocation before us is not free.
338   // These variables are undefined in the middle of allocations / free blocks.
339   uint32_t prev_free_;
340   // Allocation size of this object in the large-object alignment value as the unit.
341   uint32_t alloc_size_;
342 };
343 
GetSlotIndexForAllocationInfo(const AllocationInfo * info) const344 size_t FreeListSpace::GetSlotIndexForAllocationInfo(const AllocationInfo* info) const {
345   DCHECK_GE(info, allocation_info_);
346   DCHECK_LE(info, reinterpret_cast<AllocationInfo*>(allocation_info_map_.End()));
347   return info - allocation_info_;
348 }
349 
GetAllocationInfoForAddress(uintptr_t address)350 AllocationInfo* FreeListSpace::GetAllocationInfoForAddress(uintptr_t address) {
351   return &allocation_info_[GetSlotIndexForAddress(address)];
352 }
353 
GetAllocationInfoForAddress(uintptr_t address) const354 const AllocationInfo* FreeListSpace::GetAllocationInfoForAddress(uintptr_t address) const {
355   return &allocation_info_[GetSlotIndexForAddress(address)];
356 }
357 
operator ()(const AllocationInfo * a,const AllocationInfo * b) const358 inline bool FreeListSpace::SortByPrevFree::operator()(const AllocationInfo* a,
359                                                       const AllocationInfo* b) const {
360   if (a->GetPrevFree() < b->GetPrevFree()) return true;
361   if (a->GetPrevFree() > b->GetPrevFree()) return false;
362   if (a->AlignSize() < b->AlignSize()) return true;
363   if (a->AlignSize() > b->AlignSize()) return false;
364   return reinterpret_cast<uintptr_t>(a) < reinterpret_cast<uintptr_t>(b);
365 }
366 
Create(const std::string & name,size_t size)367 FreeListSpace* FreeListSpace::Create(const std::string& name, size_t size) {
368   CHECK_ALIGNED_PARAM(size, ObjectAlignment());
369   DCHECK_LE(gPageSize, ObjectAlignment())
370       << "MapAnonymousAligned() should be used if the large-object alignment is larger than the "
371          "runtime page size";
372   std::string error_msg;
373   MemMap mem_map = MemMap::MapAnonymous(name.c_str(),
374                                         size,
375                                         PROT_READ | PROT_WRITE,
376                                         /*low_4gb=*/true,
377                                         &error_msg);
378   CHECK(mem_map.IsValid()) << "Failed to allocate large object space mem map: " << error_msg;
379   return new FreeListSpace(name, std::move(mem_map), mem_map.Begin(), mem_map.End());
380 }
381 
FreeListSpace(const std::string & name,MemMap && mem_map,uint8_t * begin,uint8_t * end)382 FreeListSpace::FreeListSpace(const std::string& name,
383                              MemMap&& mem_map,
384                              uint8_t* begin,
385                              uint8_t* end)
386     : LargeObjectSpace(name, begin, end, "free list space lock"),
387       mem_map_(std::move(mem_map)) {
388   const size_t space_capacity = end - begin;
389   free_end_ = space_capacity;
390   CHECK_ALIGNED_PARAM(space_capacity, ObjectAlignment());
391   const size_t alloc_info_size = sizeof(AllocationInfo) * (space_capacity / ObjectAlignment());
392   std::string error_msg;
393   allocation_info_map_ =
394       MemMap::MapAnonymous("large object free list space allocation info map",
395                            alloc_info_size,
396                            PROT_READ | PROT_WRITE,
397                            /*low_4gb=*/ false,
398                            &error_msg);
399   CHECK(allocation_info_map_.IsValid()) << "Failed to allocate allocation info map" << error_msg;
400   allocation_info_ = reinterpret_cast<AllocationInfo*>(allocation_info_map_.Begin());
401 }
402 
ClampGrowthLimit(size_t new_capacity)403 void FreeListSpace::ClampGrowthLimit(size_t new_capacity) {
404   MutexLock mu(Thread::Current(), lock_);
405   new_capacity = RoundUp(new_capacity, ObjectAlignment());
406   CHECK_LE(new_capacity, Size());
407   size_t diff = Size() - new_capacity;
408   // If we don't have enough free-bytes at the end to clamp, then do the best
409   // that we can.
410   if (diff > free_end_) {
411     new_capacity = Size() - free_end_;
412     diff = free_end_;
413   }
414 
415   size_t alloc_info_size = sizeof(AllocationInfo) * (new_capacity / ObjectAlignment());
416   allocation_info_map_.SetSize(alloc_info_size);
417   mem_map_.SetSize(new_capacity);
418   // We don't need to change anything in 'free_blocks_' as the free block at
419   // the end of the space isn't in there.
420   free_end_ -= diff;
421   end_ -= diff;
422 }
423 
~FreeListSpace()424 FreeListSpace::~FreeListSpace() {}
425 
Walk(DlMallocSpace::WalkCallback callback,void * arg)426 void FreeListSpace::Walk(DlMallocSpace::WalkCallback callback, void* arg) {
427   MutexLock mu(Thread::Current(), lock_);
428   const uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
429   AllocationInfo* cur_info = &allocation_info_[0];
430   const AllocationInfo* end_info = GetAllocationInfoForAddress(free_end_start);
431   while (cur_info < end_info) {
432     if (!cur_info->IsFree()) {
433       size_t alloc_size = cur_info->ByteSize();
434       uint8_t* byte_start = reinterpret_cast<uint8_t*>(GetAddressForAllocationInfo(cur_info));
435       uint8_t* byte_end = byte_start + alloc_size;
436       callback(byte_start, byte_end, alloc_size, arg);
437       callback(nullptr, nullptr, 0, arg);
438     }
439     cur_info = cur_info->GetNextInfo();
440   }
441   CHECK_EQ(cur_info, end_info);
442 }
443 
ForEachMemMap(std::function<void (const MemMap &)> func) const444 void FreeListSpace::ForEachMemMap(std::function<void(const MemMap&)> func) const {
445   MutexLock mu(Thread::Current(), lock_);
446   func(allocation_info_map_);
447   func(mem_map_);
448 }
449 
RemoveFreePrev(AllocationInfo * info)450 void FreeListSpace::RemoveFreePrev(AllocationInfo* info) {
451   CHECK_GT(info->GetPrevFree(), 0U);
452   auto it = free_blocks_.lower_bound(info);
453   CHECK(it != free_blocks_.end());
454   CHECK_EQ(*it, info);
455   free_blocks_.erase(it);
456 }
457 
Free(Thread * self,mirror::Object * obj)458 size_t FreeListSpace::Free(Thread* self, mirror::Object* obj) {
459   DCHECK(Contains(obj)) << reinterpret_cast<void*>(Begin()) << " " << obj << " "
460                         << reinterpret_cast<void*>(End());
461   DCHECK_ALIGNED_PARAM(obj, ObjectAlignment());
462   AllocationInfo* info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(obj));
463   DCHECK(!info->IsFree());
464   const size_t allocation_size = info->ByteSize();
465   DCHECK_GT(allocation_size, 0U);
466   DCHECK_ALIGNED_PARAM(allocation_size, ObjectAlignment());
467 
468   // madvise the pages without lock
469   madvise(obj, allocation_size, MADV_DONTNEED);
470   if (kIsDebugBuild) {
471     // Can't disallow reads since we use them to find next chunks during coalescing.
472     CheckedCall(mprotect, __FUNCTION__, obj, allocation_size, PROT_READ);
473   }
474 
475   MutexLock mu(self, lock_);
476   info->SetByteSize(allocation_size, true);  // Mark as free.
477   // Look at the next chunk.
478   AllocationInfo* next_info = info->GetNextInfo();
479   // Calculate the start of the end free block.
480   uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
481   size_t prev_free_bytes = info->GetPrevFreeBytes();
482   size_t new_free_size = allocation_size;
483   if (prev_free_bytes != 0) {
484     // Coalesce with previous free chunk.
485     new_free_size += prev_free_bytes;
486     RemoveFreePrev(info);
487     info = info->GetPrevFreeInfo();
488     // The previous allocation info must not be free since we are supposed to always coalesce.
489     DCHECK_EQ(info->GetPrevFreeBytes(), 0U) << "Previous allocation was free";
490   }
491   // NOTE: next_info could be pointing right after the allocation_info_map_
492   // when freeing object in the very end of the space. But that's safe
493   // as we don't dereference it in that case. We only use it to calculate
494   // next_addr using offset within the map.
495   uintptr_t next_addr = GetAddressForAllocationInfo(next_info);
496   if (next_addr >= free_end_start) {
497     // Easy case, the next chunk is the end free region.
498     CHECK_EQ(next_addr, free_end_start);
499     free_end_ += new_free_size;
500   } else {
501     AllocationInfo* new_free_info;
502     if (next_info->IsFree()) {
503       AllocationInfo* next_next_info = next_info->GetNextInfo();
504       // Next next info can't be free since we always coalesce.
505       DCHECK(!next_next_info->IsFree());
506       DCHECK_ALIGNED_PARAM(next_next_info->ByteSize(), ObjectAlignment());
507       new_free_info = next_next_info;
508       new_free_size += next_next_info->GetPrevFreeBytes();
509       RemoveFreePrev(next_next_info);
510     } else {
511       new_free_info = next_info;
512     }
513     new_free_info->SetPrevFreeBytes(new_free_size);
514     free_blocks_.insert(new_free_info);
515     info->SetByteSize(new_free_size, true);
516     DCHECK_EQ(info->GetNextInfo(), new_free_info);
517   }
518   --num_objects_allocated_;
519   DCHECK_LE(allocation_size, num_bytes_allocated_);
520   num_bytes_allocated_ -= allocation_size;
521   return allocation_size;
522 }
523 
AllocationSize(mirror::Object * obj,size_t * usable_size)524 size_t FreeListSpace::AllocationSize(mirror::Object* obj, size_t* usable_size) {
525   DCHECK(Contains(obj));
526   AllocationInfo* info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(obj));
527   DCHECK(!info->IsFree());
528   size_t alloc_size = info->ByteSize();
529   if (usable_size != nullptr) {
530     *usable_size = alloc_size;
531   }
532   return alloc_size;
533 }
534 
Alloc(Thread * self,size_t num_bytes,size_t * bytes_allocated,size_t * usable_size,size_t * bytes_tl_bulk_allocated)535 mirror::Object* FreeListSpace::Alloc(Thread* self, size_t num_bytes, size_t* bytes_allocated,
536                                      size_t* usable_size, size_t* bytes_tl_bulk_allocated) {
537   MutexLock mu(self, lock_);
538   const size_t allocation_size = RoundUp(num_bytes, ObjectAlignment());
539   AllocationInfo temp_info;
540   temp_info.SetPrevFreeBytes(allocation_size);
541   temp_info.SetByteSize(0, false);
542   AllocationInfo* new_info;
543   // Find the smallest chunk at least num_bytes in size.
544   auto it = free_blocks_.lower_bound(&temp_info);
545   if (it != free_blocks_.end()) {
546     AllocationInfo* info = *it;
547     free_blocks_.erase(it);
548     // Fit our object in the previous allocation info free space.
549     new_info = info->GetPrevFreeInfo();
550     // Remove the newly allocated block from the info and update the prev_free_.
551     info->SetPrevFreeBytes(info->GetPrevFreeBytes() - allocation_size);
552     if (info->GetPrevFreeBytes() > 0) {
553       AllocationInfo* new_free = info - info->GetPrevFree();
554       new_free->SetPrevFreeBytes(0);
555       new_free->SetByteSize(info->GetPrevFreeBytes(), true);
556       // If there is remaining space, insert back into the free set.
557       free_blocks_.insert(info);
558     }
559   } else {
560     // Try to steal some memory from the free space at the end of the space.
561     if (LIKELY(free_end_ >= allocation_size)) {
562       // Fit our object at the start of the end free block.
563       new_info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(End()) - free_end_);
564       free_end_ -= allocation_size;
565     } else {
566       return nullptr;
567     }
568   }
569   DCHECK(bytes_allocated != nullptr);
570   *bytes_allocated = allocation_size;
571   if (usable_size != nullptr) {
572     *usable_size = allocation_size;
573   }
574   DCHECK(bytes_tl_bulk_allocated != nullptr);
575   *bytes_tl_bulk_allocated = allocation_size;
576   // Need to do these inside of the lock.
577   ++num_objects_allocated_;
578   ++total_objects_allocated_;
579   num_bytes_allocated_ += allocation_size;
580   total_bytes_allocated_ += allocation_size;
581   mirror::Object* obj = reinterpret_cast<mirror::Object*>(GetAddressForAllocationInfo(new_info));
582   // We always put our object at the start of the free block, there cannot be another free block
583   // before it.
584   if (kIsDebugBuild) {
585     CheckedCall(mprotect, __FUNCTION__, obj, allocation_size, PROT_READ | PROT_WRITE);
586   }
587   new_info->SetPrevFreeBytes(0);
588   new_info->SetByteSize(allocation_size, false);
589   return obj;
590 }
591 
Dump(std::ostream & os) const592 void FreeListSpace::Dump(std::ostream& os) const {
593   MutexLock mu(Thread::Current(), lock_);
594   os << GetName() << " -"
595      << " begin: " << reinterpret_cast<void*>(Begin())
596      << " end: " << reinterpret_cast<void*>(End()) << "\n";
597   uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
598   const AllocationInfo* cur_info =
599       GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(Begin()));
600   const AllocationInfo* end_info = GetAllocationInfoForAddress(free_end_start);
601   while (cur_info < end_info) {
602     size_t size = cur_info->ByteSize();
603     uintptr_t address = GetAddressForAllocationInfo(cur_info);
604     if (cur_info->IsFree()) {
605       os << "Free block at address: " << reinterpret_cast<const void*>(address)
606          << " of length " << size << " bytes\n";
607     } else {
608       os << "Large object at address: " << reinterpret_cast<const void*>(address)
609          << " of length " << size << " bytes\n";
610     }
611     cur_info = cur_info->GetNextInfo();
612   }
613   if (free_end_) {
614     os << "Free block at address: " << reinterpret_cast<const void*>(free_end_start)
615        << " of length " << free_end_ << " bytes\n";
616   }
617 }
618 
IsZygoteLargeObject(Thread * self,mirror::Object * obj) const619 bool FreeListSpace::IsZygoteLargeObject([[maybe_unused]] Thread* self, mirror::Object* obj) const {
620   const AllocationInfo* info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(obj));
621   DCHECK(info != nullptr);
622   return info->IsZygoteObject();
623 }
624 
SetAllLargeObjectsAsZygoteObjects(Thread * self,bool set_mark_bit)625 void FreeListSpace::SetAllLargeObjectsAsZygoteObjects(Thread* self, bool set_mark_bit) {
626   MutexLock mu(self, lock_);
627   uintptr_t free_end_start = reinterpret_cast<uintptr_t>(end_) - free_end_;
628   for (AllocationInfo* cur_info = GetAllocationInfoForAddress(reinterpret_cast<uintptr_t>(Begin())),
629       *end_info = GetAllocationInfoForAddress(free_end_start); cur_info < end_info;
630       cur_info = cur_info->GetNextInfo()) {
631     if (!cur_info->IsFree()) {
632       cur_info->SetZygoteObject();
633       if (set_mark_bit) {
634         ObjPtr<mirror::Object> obj =
635             reinterpret_cast<mirror::Object*>(GetAddressForAllocationInfo(cur_info));
636         bool success = obj->AtomicSetMarkBit(0, 1);
637         CHECK(success);
638       }
639     }
640   }
641 }
642 
SweepCallback(size_t num_ptrs,mirror::Object ** ptrs,void * arg)643 void LargeObjectSpace::SweepCallback(size_t num_ptrs, mirror::Object** ptrs, void* arg) {
644   SweepCallbackContext* context = static_cast<SweepCallbackContext*>(arg);
645   space::LargeObjectSpace* space = context->space->AsLargeObjectSpace();
646   Thread* self = context->self;
647   Locks::heap_bitmap_lock_->AssertExclusiveHeld(self);
648   // If the bitmaps aren't swapped we need to clear the bits since the GC isn't going to re-swap
649   // the bitmaps as an optimization.
650   if (!context->swap_bitmaps) {
651     accounting::LargeObjectBitmap* bitmap = space->GetLiveBitmap();
652     for (size_t i = 0; i < num_ptrs; ++i) {
653       bitmap->Clear(ptrs[i]);
654     }
655   }
656   context->freed.objects += num_ptrs;
657   context->freed.bytes += space->FreeList(self, num_ptrs, ptrs);
658 }
659 
Sweep(bool swap_bitmaps)660 collector::ObjectBytePair LargeObjectSpace::Sweep(bool swap_bitmaps) {
661   if (Begin() >= End()) {
662     return collector::ObjectBytePair(0, 0);
663   }
664   accounting::LargeObjectBitmap* live_bitmap = GetLiveBitmap();
665   accounting::LargeObjectBitmap* mark_bitmap = GetMarkBitmap();
666   if (swap_bitmaps) {
667     std::swap(live_bitmap, mark_bitmap);
668   }
669   AllocSpace::SweepCallbackContext scc(swap_bitmaps, this);
670   std::pair<uint8_t*, uint8_t*> range = GetBeginEndAtomic();
671   accounting::LargeObjectBitmap::SweepWalk(*live_bitmap, *mark_bitmap,
672                                            reinterpret_cast<uintptr_t>(range.first),
673                                            reinterpret_cast<uintptr_t>(range.second),
674                                            SweepCallback,
675                                            &scc);
676   return scc.freed;
677 }
678 
LogFragmentationAllocFailure(std::ostream &,size_t)679 bool LargeObjectSpace::LogFragmentationAllocFailure(std::ostream& /*os*/,
680                                                     size_t /*failed_alloc_bytes*/) {
681   UNIMPLEMENTED(FATAL);
682   UNREACHABLE();
683 }
684 
GetBeginEndAtomic() const685 std::pair<uint8_t*, uint8_t*> LargeObjectMapSpace::GetBeginEndAtomic() const {
686   MutexLock mu(Thread::Current(), lock_);
687   return std::make_pair(Begin(), End());
688 }
689 
GetBeginEndAtomic() const690 std::pair<uint8_t*, uint8_t*> FreeListSpace::GetBeginEndAtomic() const {
691   MutexLock mu(Thread::Current(), lock_);
692   return std::make_pair(Begin(), End());
693 }
694 
695 }  // namespace space
696 }  // namespace gc
697 }  // namespace art
698