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/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "malloc_space.h"
#include <ostream>
#include "android-base/stringprintf.h"
#include "base/logging.h" // For VLOG
#include "base/mutex-inl.h"
#include "base/utils.h"
#include "gc/accounting/card_table-inl.h"
#include "gc/accounting/space_bitmap-inl.h"
#include "gc/heap.h"
#include "gc/space/space-inl.h"
#include "gc/space/zygote_space.h"
#include "handle_scope-inl.h"
#include "mirror/class-inl.h"
#include "mirror/object-inl.h"
#include "runtime.h"
#include "thread.h"
#include "thread_list.h"
namespace art {
namespace gc {
namespace space {
using android::base::StringPrintf;
size_t MallocSpace::bitmap_index_ = 0;
MallocSpace::MallocSpace(const std::string& name,
MemMap&& mem_map,
uint8_t* begin,
uint8_t* end,
uint8_t* limit,
size_t growth_limit,
bool create_bitmaps,
bool can_move_objects,
size_t starting_size,
size_t initial_size)
: ContinuousMemMapAllocSpace(
name, std::move(mem_map), begin, end, limit, kGcRetentionPolicyAlwaysCollect),
recent_free_pos_(0), lock_("allocation space lock", kAllocSpaceLock),
growth_limit_(growth_limit), can_move_objects_(can_move_objects),
starting_size_(starting_size), initial_size_(initial_size) {
if (create_bitmaps) {
size_t bitmap_index = bitmap_index_++;
static const uintptr_t kGcCardSize = static_cast<uintptr_t>(accounting::CardTable::kCardSize);
CHECK_ALIGNED(reinterpret_cast<uintptr_t>(mem_map_.Begin()), kGcCardSize);
CHECK_ALIGNED(reinterpret_cast<uintptr_t>(mem_map_.End()), kGcCardSize);
live_bitmap_ = accounting::ContinuousSpaceBitmap::Create(
StringPrintf("allocspace %s live-bitmap %d", name.c_str(), static_cast<int>(bitmap_index)),
Begin(), NonGrowthLimitCapacity());
CHECK(live_bitmap_.IsValid()) << "could not create allocspace live bitmap #"
<< bitmap_index;
mark_bitmap_ = accounting::ContinuousSpaceBitmap::Create(
StringPrintf("allocspace %s mark-bitmap %d", name.c_str(), static_cast<int>(bitmap_index)),
Begin(), NonGrowthLimitCapacity());
CHECK(mark_bitmap_.IsValid()) << "could not create allocspace mark bitmap #" << bitmap_index;
}
for (auto& freed : recent_freed_objects_) {
freed.first = nullptr;
freed.second = nullptr;
}
}
MemMap MallocSpace::CreateMemMap(const std::string& name,
size_t starting_size,
size_t* initial_size,
size_t* growth_limit,
size_t* capacity) {
// Consistency check of the arguments.
if (starting_size > *initial_size) {
*initial_size = starting_size;
}
if (*initial_size > *growth_limit) {
LOG(ERROR) << "Failed to create alloc space (" << name << ") where the initial size ("
<< PrettySize(*initial_size) << ") is larger than its capacity ("
<< PrettySize(*growth_limit) << ")";
return MemMap::Invalid();
}
if (*growth_limit > *capacity) {
LOG(ERROR) << "Failed to create alloc space (" << name << ") where the growth limit capacity ("
<< PrettySize(*growth_limit) << ") is larger than the capacity ("
<< PrettySize(*capacity) << ")";
return MemMap::Invalid();
}
// Page align growth limit and capacity which will be used to manage mmapped storage
*growth_limit = RoundUp(*growth_limit, kPageSize);
*capacity = RoundUp(*capacity, kPageSize);
std::string error_msg;
MemMap mem_map = MemMap::MapAnonymous(name.c_str(),
*capacity,
PROT_READ | PROT_WRITE,
/*low_4gb=*/ true,
&error_msg);
if (!mem_map.IsValid()) {
LOG(ERROR) << "Failed to allocate pages for alloc space (" << name << ") of size "
<< PrettySize(*capacity) << ": " << error_msg;
}
return mem_map;
}
mirror::Class* MallocSpace::FindRecentFreedObject(const mirror::Object* obj) {
size_t pos = recent_free_pos_;
// Start at the most recently freed object and work our way back since there may be duplicates
// caused by dlmalloc reusing memory.
if (kRecentFreeCount > 0) {
for (size_t i = 0; i + 1 < kRecentFreeCount + 1; ++i) {
pos = pos != 0 ? pos - 1 : kRecentFreeMask;
if (recent_freed_objects_[pos].first == obj) {
return recent_freed_objects_[pos].second;
}
}
}
return nullptr;
}
void MallocSpace::RegisterRecentFree(mirror::Object* ptr) {
// No verification since the object is dead.
recent_freed_objects_[recent_free_pos_] = std::make_pair(ptr, ptr->GetClass<kVerifyNone>());
recent_free_pos_ = (recent_free_pos_ + 1) & kRecentFreeMask;
}
void MallocSpace::SetGrowthLimit(size_t growth_limit) {
growth_limit = RoundUp(growth_limit, kPageSize);
growth_limit_ = growth_limit;
if (Size() > growth_limit_) {
SetEnd(begin_ + growth_limit);
}
}
void* MallocSpace::MoreCore(intptr_t increment) {
CheckMoreCoreForPrecondition();
uint8_t* original_end = End();
if (increment != 0) {
VLOG(heap) << "MallocSpace::MoreCore " << PrettySize(increment);
uint8_t* new_end = original_end + increment;
if (increment > 0) {
// Should never be asked to increase the allocation beyond the capacity of the space. Enforced
// by mspace_set_footprint_limit.
CHECK_LE(new_end, Begin() + Capacity());
CheckedCall(mprotect, GetName(), original_end, increment, PROT_READ | PROT_WRITE);
} else {
// Should never be asked for negative footprint (ie before begin). Zero footprint is ok.
CHECK_GE(original_end + increment, Begin());
// Advise we don't need the pages and protect them
// TODO: by removing permissions to the pages we may be causing TLB shoot-down which can be
// expensive (note the same isn't true for giving permissions to a page as the protected
// page shouldn't be in a TLB). We should investigate performance impact of just
// removing ignoring the memory protection change here and in Space::CreateAllocSpace. It's
// likely just a useful debug feature.
size_t size = -increment;
CheckedCall(madvise, GetName(), new_end, size, MADV_DONTNEED);
CheckedCall(mprotect, GetName(), new_end, size, PROT_NONE);
}
// Update end_.
SetEnd(new_end);
}
return original_end;
}
ZygoteSpace* MallocSpace::CreateZygoteSpace(const char* alloc_space_name, bool low_memory_mode,
MallocSpace** out_malloc_space) {
// For RosAlloc, revoke thread local runs before creating a new
// alloc space so that we won't mix thread local runs from different
// alloc spaces.
RevokeAllThreadLocalBuffers();
SetEnd(reinterpret_cast<uint8_t*>(RoundUp(reinterpret_cast<uintptr_t>(End()), kPageSize)));
DCHECK_ALIGNED(begin_, accounting::CardTable::kCardSize);
DCHECK_ALIGNED(End(), accounting::CardTable::kCardSize);
DCHECK_ALIGNED(begin_, kPageSize);
DCHECK_ALIGNED(End(), kPageSize);
size_t size = RoundUp(Size(), kPageSize);
// Trimming the heap should be done by the caller since we may have invalidated the accounting
// stored in between objects.
// Remaining size is for the new alloc space.
const size_t growth_limit = growth_limit_ - size;
// Use mem map limit in case error for clear growth limit.
const size_t capacity = NonGrowthLimitCapacity() - size;
VLOG(heap) << "Begin " << reinterpret_cast<const void*>(begin_) << "\n"
<< "End " << reinterpret_cast<const void*>(End()) << "\n"
<< "Size " << size << "\n"
<< "GrowthLimit " << growth_limit_ << "\n"
<< "Capacity " << Capacity();
SetGrowthLimit(RoundUp(size, kPageSize));
// FIXME: Do we need reference counted pointers here?
// Make the two spaces share the same mark bitmaps since the bitmaps span both of the spaces.
VLOG(heap) << "Creating new AllocSpace: ";
VLOG(heap) << "Size " << GetMemMap()->Size();
VLOG(heap) << "GrowthLimit " << PrettySize(growth_limit);
VLOG(heap) << "Capacity " << PrettySize(capacity);
// Remap the tail.
std::string error_msg;
MemMap mem_map = GetMemMap()->RemapAtEnd(
End(), alloc_space_name, PROT_READ | PROT_WRITE, &error_msg);
CHECK(mem_map.IsValid()) << error_msg;
void* allocator =
CreateAllocator(End(), starting_size_, initial_size_, capacity, low_memory_mode);
// Protect memory beyond the initial size.
uint8_t* end = mem_map.Begin() + starting_size_;
if (capacity > initial_size_) {
CheckedCall(mprotect, alloc_space_name, end, capacity - initial_size_, PROT_NONE);
}
*out_malloc_space = CreateInstance(std::move(mem_map),
alloc_space_name,
allocator,
End(),
end,
limit_,
growth_limit,
CanMoveObjects());
SetLimit(End());
live_bitmap_.SetHeapLimit(reinterpret_cast<uintptr_t>(End()));
CHECK_EQ(live_bitmap_.HeapLimit(), reinterpret_cast<uintptr_t>(End()));
mark_bitmap_.SetHeapLimit(reinterpret_cast<uintptr_t>(End()));
CHECK_EQ(mark_bitmap_.HeapLimit(), reinterpret_cast<uintptr_t>(End()));
// Create the actual zygote space.
ZygoteSpace* zygote_space = ZygoteSpace::Create("Zygote space",
ReleaseMemMap(),
std::move(live_bitmap_),
std::move(mark_bitmap_));
if (UNLIKELY(zygote_space == nullptr)) {
VLOG(heap) << "Failed creating zygote space from space " << GetName();
} else {
VLOG(heap) << "zygote space creation done";
}
return zygote_space;
}
void MallocSpace::Dump(std::ostream& os) const {
os << GetType()
<< " begin=" << reinterpret_cast<void*>(Begin())
<< ",end=" << reinterpret_cast<void*>(End())
<< ",limit=" << reinterpret_cast<void*>(Limit())
<< ",size=" << PrettySize(Size()) << ",capacity=" << PrettySize(Capacity())
<< ",non_growth_limit_capacity=" << PrettySize(NonGrowthLimitCapacity())
<< ",name=\"" << GetName() << "\"]";
}
void MallocSpace::SweepCallback(size_t num_ptrs, mirror::Object** ptrs, void* arg) {
SweepCallbackContext* context = static_cast<SweepCallbackContext*>(arg);
space::MallocSpace* space = context->space->AsMallocSpace();
Thread* self = context->self;
Locks::heap_bitmap_lock_->AssertExclusiveHeld(self);
// If the bitmaps aren't swapped we need to clear the bits since the GC isn't going to re-swap
// the bitmaps as an optimization.
if (!context->swap_bitmaps) {
accounting::ContinuousSpaceBitmap* bitmap = space->GetLiveBitmap();
for (size_t i = 0; i < num_ptrs; ++i) {
bitmap->Clear(ptrs[i]);
}
}
// Use a bulk free, that merges consecutive objects before freeing or free per object?
// Documentation suggests better free performance with merging, but this may be at the expense
// of allocation.
context->freed.objects += num_ptrs;
context->freed.bytes += space->FreeList(self, num_ptrs, ptrs);
}
void MallocSpace::ClampGrowthLimit() {
size_t new_capacity = Capacity();
CHECK_LE(new_capacity, NonGrowthLimitCapacity());
GetLiveBitmap()->SetHeapSize(new_capacity);
GetMarkBitmap()->SetHeapSize(new_capacity);
if (temp_bitmap_.IsValid()) {
// If the bitmaps are clamped, then the temp bitmap is actually the mark bitmap.
temp_bitmap_.SetHeapSize(new_capacity);
}
GetMemMap()->SetSize(new_capacity);
limit_ = Begin() + new_capacity;
}
} // namespace space
} // namespace gc
} // namespace art