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android / platform / art / 1e13374baf7dfaf442ffbf9809c37c131d681eaf / . / runtime / gc / allocator / rosalloc.cc
blob: bd10f7bbf0ff7f6baa732deacd8780757f03d83a [file] [log] [blame]
/*
* 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 "rosalloc.h"
#include "base/memory_tool.h"
#include "base/mutex-inl.h"
#include "gc/space/memory_tool_settings.h"
#include "mem_map.h"
#include "mirror/class-inl.h"
#include "mirror/object.h"
#include "mirror/object-inl.h"
#include "thread-inl.h"
#include "thread_list.h"
#include <map>
#include <list>
#include <sstream>
#include <vector>
namespace art {
namespace gc {
namespace allocator {
static constexpr bool kUsePrefetchDuringAllocRun = true;
static constexpr bool kPrefetchNewRunDataByZeroing = false;
static constexpr size_t kPrefetchStride = 64;
size_t RosAlloc::bracketSizes[kNumOfSizeBrackets];
size_t RosAlloc::numOfPages[kNumOfSizeBrackets];
size_t RosAlloc::numOfSlots[kNumOfSizeBrackets];
size_t RosAlloc::headerSizes[kNumOfSizeBrackets];
size_t RosAlloc::bulkFreeBitMapOffsets[kNumOfSizeBrackets];
size_t RosAlloc::threadLocalFreeBitMapOffsets[kNumOfSizeBrackets];
bool RosAlloc::initialized_ = false;
size_t RosAlloc::dedicated_full_run_storage_[kPageSize / sizeof(size_t)] = { 0 };
RosAlloc::Run* RosAlloc::dedicated_full_run_ =
reinterpret_cast<RosAlloc::Run*>(dedicated_full_run_storage_);
RosAlloc::RosAlloc(void* base, size_t capacity, size_t max_capacity,
PageReleaseMode page_release_mode, bool running_on_memory_tool,
size_t page_release_size_threshold)
: base_(reinterpret_cast<uint8_t*>(base)), footprint_(capacity),
capacity_(capacity), max_capacity_(max_capacity),
lock_("rosalloc global lock", kRosAllocGlobalLock),
bulk_free_lock_("rosalloc bulk free lock", kRosAllocBulkFreeLock),
page_release_mode_(page_release_mode),
page_release_size_threshold_(page_release_size_threshold),
is_running_on_memory_tool_(running_on_memory_tool) {
DCHECK_EQ(RoundUp(capacity, kPageSize), capacity);
DCHECK_EQ(RoundUp(max_capacity, kPageSize), max_capacity);
CHECK_LE(capacity, max_capacity);
CHECK(IsAligned<kPageSize>(page_release_size_threshold_));
if (!initialized_) {
Initialize();
}
VLOG(heap) << "RosAlloc base="
<< std::hex << (intptr_t)base_ << ", end="
<< std::hex << (intptr_t)(base_ + capacity_)
<< ", capacity=" << std::dec << capacity_
<< ", max_capacity=" << std::dec << max_capacity_;
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
size_bracket_lock_names_[i] =
StringPrintf("an rosalloc size bracket %d lock", static_cast<int>(i));
size_bracket_locks_[i] = new Mutex(size_bracket_lock_names_[i].c_str(), kRosAllocBracketLock);
current_runs_[i] = dedicated_full_run_;
}
DCHECK_EQ(footprint_, capacity_);
size_t num_of_pages = footprint_ / kPageSize;
size_t max_num_of_pages = max_capacity_ / kPageSize;
std::string error_msg;
page_map_mem_map_.reset(MemMap::MapAnonymous("rosalloc page map", nullptr,
RoundUp(max_num_of_pages, kPageSize),
PROT_READ | PROT_WRITE, false, false, &error_msg));
CHECK(page_map_mem_map_.get() != nullptr) << "Couldn't allocate the page map : " << error_msg;
page_map_ = page_map_mem_map_->Begin();
page_map_size_ = num_of_pages;
max_page_map_size_ = max_num_of_pages;
free_page_run_size_map_.resize(num_of_pages);
FreePageRun* free_pages = reinterpret_cast<FreePageRun*>(base_);
if (kIsDebugBuild) {
free_pages->magic_num_ = kMagicNumFree;
}
free_pages->SetByteSize(this, capacity_);
DCHECK_EQ(capacity_ % kPageSize, static_cast<size_t>(0));
DCHECK(free_pages->IsFree());
free_pages->ReleasePages(this);
DCHECK(free_pages->IsFree());
free_page_runs_.insert(free_pages);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::RosAlloc() : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(free_pages)
<< " into free_page_runs_";
}
}
RosAlloc::~RosAlloc() {
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
delete size_bracket_locks_[i];
}
if (is_running_on_memory_tool_) {
MEMORY_TOOL_MAKE_DEFINED(base_, capacity_);
}
}
void* RosAlloc::AllocPages(Thread* self, size_t num_pages, uint8_t page_map_type) {
lock_.AssertHeld(self);
DCHECK(page_map_type == kPageMapRun || page_map_type == kPageMapLargeObject);
FreePageRun* res = nullptr;
const size_t req_byte_size = num_pages * kPageSize;
// Find the lowest address free page run that's large enough.
for (auto it = free_page_runs_.begin(); it != free_page_runs_.end(); ) {
FreePageRun* fpr = *it;
DCHECK(fpr->IsFree());
size_t fpr_byte_size = fpr->ByteSize(this);
DCHECK_EQ(fpr_byte_size % kPageSize, static_cast<size_t>(0));
if (req_byte_size <= fpr_byte_size) {
// Found one.
free_page_runs_.erase(it++);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : Erased run 0x"
<< std::hex << reinterpret_cast<intptr_t>(fpr)
<< " from free_page_runs_";
}
if (req_byte_size < fpr_byte_size) {
// Split.
FreePageRun* remainder = reinterpret_cast<FreePageRun*>(reinterpret_cast<uint8_t*>(fpr) + req_byte_size);
if (kIsDebugBuild) {
remainder->magic_num_ = kMagicNumFree;
}
remainder->SetByteSize(this, fpr_byte_size - req_byte_size);
DCHECK_EQ(remainder->ByteSize(this) % kPageSize, static_cast<size_t>(0));
// Don't need to call madvise on remainder here.
free_page_runs_.insert(remainder);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(remainder)
<< " into free_page_runs_";
}
fpr->SetByteSize(this, req_byte_size);
DCHECK_EQ(fpr->ByteSize(this) % kPageSize, static_cast<size_t>(0));
}
res = fpr;
break;
} else {
++it;
}
}
// Failed to allocate pages. Grow the footprint, if possible.
if (UNLIKELY(res == nullptr && capacity_ > footprint_)) {
FreePageRun* last_free_page_run = nullptr;
size_t last_free_page_run_size;
auto it = free_page_runs_.rbegin();
if (it != free_page_runs_.rend() && (last_free_page_run = *it)->End(this) == base_ + footprint_) {
// There is a free page run at the end.
DCHECK(last_free_page_run->IsFree());
DCHECK(IsFreePage(ToPageMapIndex(last_free_page_run)));
last_free_page_run_size = last_free_page_run->ByteSize(this);
} else {
// There is no free page run at the end.
last_free_page_run_size = 0;
}
DCHECK_LT(last_free_page_run_size, req_byte_size);
if (capacity_ - footprint_ + last_free_page_run_size >= req_byte_size) {
// If we grow the heap, we can allocate it.
size_t increment = std::min(std::max(2 * MB, req_byte_size - last_free_page_run_size),
capacity_ - footprint_);
DCHECK_EQ(increment % kPageSize, static_cast<size_t>(0));
size_t new_footprint = footprint_ + increment;
size_t new_num_of_pages = new_footprint / kPageSize;
DCHECK_LT(page_map_size_, new_num_of_pages);
DCHECK_LT(free_page_run_size_map_.size(), new_num_of_pages);
page_map_size_ = new_num_of_pages;
DCHECK_LE(page_map_size_, max_page_map_size_);
free_page_run_size_map_.resize(new_num_of_pages);
ArtRosAllocMoreCore(this, increment);
if (last_free_page_run_size > 0) {
// There was a free page run at the end. Expand its size.
DCHECK_EQ(last_free_page_run_size, last_free_page_run->ByteSize(this));
last_free_page_run->SetByteSize(this, last_free_page_run_size + increment);
DCHECK_EQ(last_free_page_run->ByteSize(this) % kPageSize, static_cast<size_t>(0));
DCHECK_EQ(last_free_page_run->End(this), base_ + new_footprint);
} else {
// Otherwise, insert a new free page run at the end.
FreePageRun* new_free_page_run = reinterpret_cast<FreePageRun*>(base_ + footprint_);
if (kIsDebugBuild) {
new_free_page_run->magic_num_ = kMagicNumFree;
}
new_free_page_run->SetByteSize(this, increment);
DCHECK_EQ(new_free_page_run->ByteSize(this) % kPageSize, static_cast<size_t>(0));
free_page_runs_.insert(new_free_page_run);
DCHECK_EQ(*free_page_runs_.rbegin(), new_free_page_run);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AlloPages() : Grew the heap by inserting run 0x"
<< std::hex << reinterpret_cast<intptr_t>(new_free_page_run)
<< " into free_page_runs_";
}
}
DCHECK_LE(footprint_ + increment, capacity_);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : increased the footprint from "
<< footprint_ << " to " << new_footprint;
}
footprint_ = new_footprint;
// And retry the last free page run.
it = free_page_runs_.rbegin();
DCHECK(it != free_page_runs_.rend());
FreePageRun* fpr = *it;
if (kIsDebugBuild && last_free_page_run_size > 0) {
DCHECK(last_free_page_run != nullptr);
DCHECK_EQ(last_free_page_run, fpr);
}
size_t fpr_byte_size = fpr->ByteSize(this);
DCHECK_EQ(fpr_byte_size % kPageSize, static_cast<size_t>(0));
DCHECK_LE(req_byte_size, fpr_byte_size);
free_page_runs_.erase(fpr);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : Erased run 0x" << std::hex << reinterpret_cast<intptr_t>(fpr)
<< " from free_page_runs_";
}
if (req_byte_size < fpr_byte_size) {
// Split if there's a remainder.
FreePageRun* remainder = reinterpret_cast<FreePageRun*>(reinterpret_cast<uint8_t*>(fpr) + req_byte_size);
if (kIsDebugBuild) {
remainder->magic_num_ = kMagicNumFree;
}
remainder->SetByteSize(this, fpr_byte_size - req_byte_size);
DCHECK_EQ(remainder->ByteSize(this) % kPageSize, static_cast<size_t>(0));
free_page_runs_.insert(remainder);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(remainder)
<< " into free_page_runs_";
}
fpr->SetByteSize(this, req_byte_size);
DCHECK_EQ(fpr->ByteSize(this) % kPageSize, static_cast<size_t>(0));
}
res = fpr;
}
}
if (LIKELY(res != nullptr)) {
// Update the page map.
size_t page_map_idx = ToPageMapIndex(res);
for (size_t i = 0; i < num_pages; i++) {
DCHECK(IsFreePage(page_map_idx + i));
}
switch (page_map_type) {
case kPageMapRun:
page_map_[page_map_idx] = kPageMapRun;
for (size_t i = 1; i < num_pages; i++) {
page_map_[page_map_idx + i] = kPageMapRunPart;
}
break;
case kPageMapLargeObject:
page_map_[page_map_idx] = kPageMapLargeObject;
for (size_t i = 1; i < num_pages; i++) {
page_map_[page_map_idx + i] = kPageMapLargeObjectPart;
}
break;
default:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_type);
break;
}
if (kIsDebugBuild) {
// Clear the first page since it is not madvised due to the magic number.
memset(res, 0, kPageSize);
}
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : 0x" << std::hex << reinterpret_cast<intptr_t>(res)
<< "-0x" << (reinterpret_cast<intptr_t>(res) + num_pages * kPageSize)
<< "(" << std::dec << (num_pages * kPageSize) << ")";
}
return res;
}
// Fail.
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocPages() : nullptr";
}
return nullptr;
}
size_t RosAlloc::FreePages(Thread* self, void* ptr, bool already_zero) {
lock_.AssertHeld(self);
size_t pm_idx = ToPageMapIndex(ptr);
DCHECK_LT(pm_idx, page_map_size_);
uint8_t pm_type = page_map_[pm_idx];
DCHECK(pm_type == kPageMapRun || pm_type == kPageMapLargeObject);
uint8_t pm_part_type;
switch (pm_type) {
case kPageMapRun:
pm_part_type = kPageMapRunPart;
break;
case kPageMapLargeObject:
pm_part_type = kPageMapLargeObjectPart;
break;
default:
LOG(FATAL) << "Unreachable - " << __PRETTY_FUNCTION__ << " : " << "pm_idx=" << pm_idx << ", pm_type="
<< static_cast<int>(pm_type) << ", ptr=" << std::hex
<< reinterpret_cast<intptr_t>(ptr);
return 0;
}
// Update the page map and count the number of pages.
size_t num_pages = 1;
page_map_[pm_idx] = kPageMapEmpty;
size_t idx = pm_idx + 1;
size_t end = page_map_size_;
while (idx < end && page_map_[idx] == pm_part_type) {
page_map_[idx] = kPageMapEmpty;
num_pages++;
idx++;
}
const size_t byte_size = num_pages * kPageSize;
if (already_zero) {
if (ShouldCheckZeroMemory()) {
const uintptr_t* word_ptr = reinterpret_cast<uintptr_t*>(ptr);
for (size_t i = 0; i < byte_size / sizeof(uintptr_t); ++i) {
CHECK_EQ(word_ptr[i], 0U) << "words don't match at index " << i;
}
}
} else if (!DoesReleaseAllPages()) {
memset(ptr, 0, byte_size);
}
if (kTraceRosAlloc) {
LOG(INFO) << __PRETTY_FUNCTION__ << " : 0x" << std::hex << reinterpret_cast<intptr_t>(ptr)
<< "-0x" << (reinterpret_cast<intptr_t>(ptr) + byte_size)
<< "(" << std::dec << (num_pages * kPageSize) << ")";
}
// Turn it into a free run.
FreePageRun* fpr = reinterpret_cast<FreePageRun*>(ptr);
if (kIsDebugBuild) {
fpr->magic_num_ = kMagicNumFree;
}
fpr->SetByteSize(this, byte_size);
DCHECK(IsAligned<kPageSize>(fpr->ByteSize(this)));
DCHECK(free_page_runs_.find(fpr) == free_page_runs_.end());
if (!free_page_runs_.empty()) {
// Try to coalesce in the higher address direction.
if (kTraceRosAlloc) {
LOG(INFO) << __PRETTY_FUNCTION__ << "RosAlloc::FreePages() : trying to coalesce a free page run 0x"
<< std::hex << reinterpret_cast<uintptr_t>(fpr) << " [" << std::dec << pm_idx << "] -0x"
<< std::hex << reinterpret_cast<uintptr_t>(fpr->End(this)) << " [" << std::dec
<< (fpr->End(this) == End() ? page_map_size_ : ToPageMapIndex(fpr->End(this))) << "]";
}
auto higher_it = free_page_runs_.upper_bound(fpr);
if (higher_it != free_page_runs_.end()) {
for (auto it = higher_it; it != free_page_runs_.end(); ) {
FreePageRun* h = *it;
DCHECK_EQ(h->ByteSize(this) % kPageSize, static_cast<size_t>(0));
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreePages() : trying to coalesce with a higher free page run 0x"
<< std::hex << reinterpret_cast<uintptr_t>(h) << " [" << std::dec << ToPageMapIndex(h) << "] -0x"
<< std::hex << reinterpret_cast<uintptr_t>(h->End(this)) << " [" << std::dec
<< (h->End(this) == End() ? page_map_size_ : ToPageMapIndex(h->End(this))) << "]";
}
if (fpr->End(this) == h->Begin()) {
if (kTraceRosAlloc) {
LOG(INFO) << "Success";
}
// Clear magic num since this is no longer the start of a free page run.
if (kIsDebugBuild) {
h->magic_num_ = 0;
}
free_page_runs_.erase(it++);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreePages() : (coalesce) Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(h)
<< " from free_page_runs_";
}
fpr->SetByteSize(this, fpr->ByteSize(this) + h->ByteSize(this));
DCHECK_EQ(fpr->ByteSize(this) % kPageSize, static_cast<size_t>(0));
} else {
// Not adjacent. Stop.
if (kTraceRosAlloc) {
LOG(INFO) << "Fail";
}
break;
}
}
}
// Try to coalesce in the lower address direction.
auto lower_it = free_page_runs_.upper_bound(fpr);
if (lower_it != free_page_runs_.begin()) {
--lower_it;
for (auto it = lower_it; ; ) {
// We want to try to coalesce with the first element but
// there's no "<=" operator for the iterator.
bool to_exit_loop = it == free_page_runs_.begin();
FreePageRun* l = *it;
DCHECK_EQ(l->ByteSize(this) % kPageSize, static_cast<size_t>(0));
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreePages() : trying to coalesce with a lower free page run 0x"
<< std::hex << reinterpret_cast<uintptr_t>(l) << " [" << std::dec << ToPageMapIndex(l) << "] -0x"
<< std::hex << reinterpret_cast<uintptr_t>(l->End(this)) << " [" << std::dec
<< (l->End(this) == End() ? page_map_size_ : ToPageMapIndex(l->End(this))) << "]";
}
if (l->End(this) == fpr->Begin()) {
if (kTraceRosAlloc) {
LOG(INFO) << "Success";
}
free_page_runs_.erase(it--);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreePages() : (coalesce) Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(l)
<< " from free_page_runs_";
}
l->SetByteSize(this, l->ByteSize(this) + fpr->ByteSize(this));
DCHECK_EQ(l->ByteSize(this) % kPageSize, static_cast<size_t>(0));
// Clear magic num since this is no longer the start of a free page run.
if (kIsDebugBuild) {
fpr->magic_num_ = 0;
}
fpr = l;
} else {
// Not adjacent. Stop.
if (kTraceRosAlloc) {
LOG(INFO) << "Fail";
}
break;
}
if (to_exit_loop) {
break;
}
}
}
}
// Insert it.
DCHECK_EQ(fpr->ByteSize(this) % kPageSize, static_cast<size_t>(0));
DCHECK(free_page_runs_.find(fpr) == free_page_runs_.end());
DCHECK(fpr->IsFree());
fpr->ReleasePages(this);
DCHECK(fpr->IsFree());
free_page_runs_.insert(fpr);
DCHECK(free_page_runs_.find(fpr) != free_page_runs_.end());
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreePages() : Inserted run 0x" << std::hex << reinterpret_cast<intptr_t>(fpr)
<< " into free_page_runs_";
}
return byte_size;
}
void* RosAlloc::AllocLargeObject(Thread* self, size_t size, size_t* bytes_allocated,
size_t* usable_size, size_t* bytes_tl_bulk_allocated) {
DCHECK(bytes_allocated != nullptr);
DCHECK(usable_size != nullptr);
DCHECK_GT(size, kLargeSizeThreshold);
size_t num_pages = RoundUp(size, kPageSize) / kPageSize;
void* r;
{
MutexLock mu(self, lock_);
r = AllocPages(self, num_pages, kPageMapLargeObject);
}
if (UNLIKELY(r == nullptr)) {
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocLargeObject() : nullptr";
}
return nullptr;
}
const size_t total_bytes = num_pages * kPageSize;
*bytes_allocated = total_bytes;
*usable_size = total_bytes;
*bytes_tl_bulk_allocated = total_bytes;
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocLargeObject() : 0x" << std::hex << reinterpret_cast<intptr_t>(r)
<< "-0x" << (reinterpret_cast<intptr_t>(r) + num_pages * kPageSize)
<< "(" << std::dec << (num_pages * kPageSize) << ")";
}
// Check if the returned memory is really all zero.
if (ShouldCheckZeroMemory()) {
CHECK_EQ(total_bytes % sizeof(uintptr_t), 0U);
const uintptr_t* words = reinterpret_cast<uintptr_t*>(r);
for (size_t i = 0; i < total_bytes / sizeof(uintptr_t); ++i) {
CHECK_EQ(words[i], 0U);
}
}
return r;
}
size_t RosAlloc::FreeInternal(Thread* self, void* ptr) {
DCHECK_LE(base_, ptr);
DCHECK_LT(ptr, base_ + footprint_);
size_t pm_idx = RoundDownToPageMapIndex(ptr);
Run* run = nullptr;
{
MutexLock mu(self, lock_);
DCHECK_LT(pm_idx, page_map_size_);
uint8_t page_map_entry = page_map_[pm_idx];
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreeInternal() : " << std::hex << ptr << ", pm_idx=" << std::dec << pm_idx
<< ", page_map_entry=" << static_cast<int>(page_map_entry);
}
switch (page_map_[pm_idx]) {
case kPageMapLargeObject:
return FreePages(self, ptr, false);
case kPageMapLargeObjectPart:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_[pm_idx]);
return 0;
case kPageMapRunPart: {
// Find the beginning of the run.
do {
--pm_idx;
DCHECK_LT(pm_idx, capacity_ / kPageSize);
} while (page_map_[pm_idx] != kPageMapRun);
FALLTHROUGH_INTENDED;
case kPageMapRun:
run = reinterpret_cast<Run*>(base_ + pm_idx * kPageSize);
DCHECK_EQ(run->magic_num_, kMagicNum);
break;
case kPageMapReleased:
case kPageMapEmpty:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_[pm_idx]);
return 0;
}
default:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_[pm_idx]);
return 0;
}
}
DCHECK(run != nullptr);
return FreeFromRun(self, ptr, run);
}
size_t RosAlloc::Free(Thread* self, void* ptr) {
ReaderMutexLock rmu(self, bulk_free_lock_);
return FreeInternal(self, ptr);
}
RosAlloc::Run* RosAlloc::AllocRun(Thread* self, size_t idx) {
RosAlloc::Run* new_run = nullptr;
{
MutexLock mu(self, lock_);
new_run = reinterpret_cast<Run*>(AllocPages(self, numOfPages[idx], kPageMapRun));
}
if (LIKELY(new_run != nullptr)) {
if (kIsDebugBuild) {
new_run->magic_num_ = kMagicNum;
}
new_run->size_bracket_idx_ = idx;
new_run->SetAllocBitMapBitsForInvalidSlots();
DCHECK(!new_run->IsThreadLocal());
DCHECK_EQ(new_run->first_search_vec_idx_, 0U);
DCHECK(!new_run->to_be_bulk_freed_);
if (kUsePrefetchDuringAllocRun && idx < kNumThreadLocalSizeBrackets) {
// Take ownership of the cache lines if we are likely to be thread local run.
if (kPrefetchNewRunDataByZeroing) {
// Zeroing the data is sometimes faster than prefetching but it increases memory usage
// since we end up dirtying zero pages which may have been madvised.
new_run->ZeroData();
} else {
const size_t num_of_slots = numOfSlots[idx];
const size_t bracket_size = bracketSizes[idx];
const size_t num_of_bytes = num_of_slots * bracket_size;
uint8_t* begin = reinterpret_cast<uint8_t*>(new_run) + headerSizes[idx];
for (size_t i = 0; i < num_of_bytes; i += kPrefetchStride) {
__builtin_prefetch(begin + i);
}
}
}
}
return new_run;
}
RosAlloc::Run* RosAlloc::RefillRun(Thread* self, size_t idx) {
// Get the lowest address non-full run from the binary tree.
auto* const bt = &non_full_runs_[idx];
if (!bt->empty()) {
// If there's one, use it as the current run.
auto it = bt->begin();
Run* non_full_run = *it;
DCHECK(non_full_run != nullptr);
DCHECK(!non_full_run->IsThreadLocal());
bt->erase(it);
return non_full_run;
}
// If there's none, allocate a new run and use it as the current run.
return AllocRun(self, idx);
}
inline void* RosAlloc::AllocFromCurrentRunUnlocked(Thread* self, size_t idx) {
Run* current_run = current_runs_[idx];
DCHECK(current_run != nullptr);
void* slot_addr = current_run->AllocSlot();
if (UNLIKELY(slot_addr == nullptr)) {
// The current run got full. Try to refill it.
DCHECK(current_run->IsFull());
if (kIsDebugBuild && current_run != dedicated_full_run_) {
full_runs_[idx].insert(current_run);
if (kTraceRosAlloc) {
LOG(INFO) << __PRETTY_FUNCTION__ << " : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(current_run)
<< " into full_runs_[" << std::dec << idx << "]";
}
DCHECK(non_full_runs_[idx].find(current_run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(current_run) != full_runs_[idx].end());
}
current_run = RefillRun(self, idx);
if (UNLIKELY(current_run == nullptr)) {
// Failed to allocate a new run, make sure that it is the dedicated full run.
current_runs_[idx] = dedicated_full_run_;
return nullptr;
}
DCHECK(current_run != nullptr);
DCHECK(non_full_runs_[idx].find(current_run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(current_run) == full_runs_[idx].end());
current_run->SetIsThreadLocal(false);
current_runs_[idx] = current_run;
DCHECK(!current_run->IsFull());
slot_addr = current_run->AllocSlot();
// Must succeed now with a new run.
DCHECK(slot_addr != nullptr);
}
return slot_addr;
}
void* RosAlloc::AllocFromRunThreadUnsafe(Thread* self, size_t size, size_t* bytes_allocated,
size_t* usable_size,
size_t* bytes_tl_bulk_allocated) {
DCHECK(bytes_allocated != nullptr);
DCHECK(usable_size != nullptr);
DCHECK(bytes_tl_bulk_allocated != nullptr);
DCHECK_LE(size, kLargeSizeThreshold);
size_t bracket_size;
size_t idx = SizeToIndexAndBracketSize(size, &bracket_size);
DCHECK_EQ(idx, SizeToIndex(size));
DCHECK_EQ(bracket_size, IndexToBracketSize(idx));
DCHECK_EQ(bracket_size, bracketSizes[idx]);
DCHECK_LE(size, bracket_size);
DCHECK(size > 512 || bracket_size - size < 16);
Locks::mutator_lock_->AssertExclusiveHeld(self);
void* slot_addr = AllocFromCurrentRunUnlocked(self, idx);
if (LIKELY(slot_addr != nullptr)) {
*bytes_allocated = bracket_size;
*usable_size = bracket_size;
*bytes_tl_bulk_allocated = bracket_size;
}
// Caller verifies that it is all 0.
return slot_addr;
}
void* RosAlloc::AllocFromRun(Thread* self, size_t size, size_t* bytes_allocated,
size_t* usable_size, size_t* bytes_tl_bulk_allocated) {
DCHECK(bytes_allocated != nullptr);
DCHECK(usable_size != nullptr);
DCHECK(bytes_tl_bulk_allocated != nullptr);
DCHECK_LE(size, kLargeSizeThreshold);
size_t bracket_size;
size_t idx = SizeToIndexAndBracketSize(size, &bracket_size);
DCHECK_EQ(idx, SizeToIndex(size));
DCHECK_EQ(bracket_size, IndexToBracketSize(idx));
DCHECK_EQ(bracket_size, bracketSizes[idx]);
DCHECK_LE(size, bracket_size);
DCHECK(size > 512 || bracket_size - size < 16);
void* slot_addr;
if (LIKELY(idx < kNumThreadLocalSizeBrackets)) {
// Use a thread-local run.
Run* thread_local_run = reinterpret_cast<Run*>(self->GetRosAllocRun(idx));
// Allow invalid since this will always fail the allocation.
if (kIsDebugBuild) {
// Need the lock to prevent race conditions.
MutexLock mu(self, *size_bracket_locks_[idx]);
CHECK(non_full_runs_[idx].find(thread_local_run) == non_full_runs_[idx].end());
CHECK(full_runs_[idx].find(thread_local_run) == full_runs_[idx].end());
}
DCHECK(thread_local_run != nullptr);
DCHECK(thread_local_run->IsThreadLocal() || thread_local_run == dedicated_full_run_);
slot_addr = thread_local_run->AllocSlot();
// The allocation must fail if the run is invalid.
DCHECK(thread_local_run != dedicated_full_run_ || slot_addr == nullptr)
<< "allocated from an invalid run";
if (UNLIKELY(slot_addr == nullptr)) {
// The run got full. Try to free slots.
DCHECK(thread_local_run->IsFull());
MutexLock mu(self, *size_bracket_locks_[idx]);
bool is_all_free_after_merge;
// This is safe to do for the dedicated_full_run_ since the bitmaps are empty.
if (thread_local_run->MergeThreadLocalFreeBitMapToAllocBitMap(&is_all_free_after_merge)) {
DCHECK_NE(thread_local_run, dedicated_full_run_);
// Some slot got freed. Keep it.
DCHECK(!thread_local_run->IsFull());
DCHECK_EQ(is_all_free_after_merge, thread_local_run->IsAllFree());
if (is_all_free_after_merge) {
// Check that the bitmap idx is back at 0 if it's all free.
DCHECK_EQ(thread_local_run->first_search_vec_idx_, 0U);
}
} else {
// No slots got freed. Try to refill the thread-local run.
DCHECK(thread_local_run->IsFull());
if (thread_local_run != dedicated_full_run_) {
thread_local_run->SetIsThreadLocal(false);
if (kIsDebugBuild) {
full_runs_[idx].insert(thread_local_run);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocFromRun() : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(thread_local_run)
<< " into full_runs_[" << std::dec << idx << "]";
}
}
DCHECK(non_full_runs_[idx].find(thread_local_run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(thread_local_run) != full_runs_[idx].end());
}
thread_local_run = RefillRun(self, idx);
if (UNLIKELY(thread_local_run == nullptr)) {
self->SetRosAllocRun(idx, dedicated_full_run_);
return nullptr;
}
DCHECK(non_full_runs_[idx].find(thread_local_run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(thread_local_run) == full_runs_[idx].end());
thread_local_run->SetIsThreadLocal(true);
self->SetRosAllocRun(idx, thread_local_run);
DCHECK(!thread_local_run->IsFull());
}
DCHECK(thread_local_run != nullptr);
DCHECK(!thread_local_run->IsFull());
DCHECK(thread_local_run->IsThreadLocal());
// Account for all the free slots in the new or refreshed thread local run.
*bytes_tl_bulk_allocated = thread_local_run->NumberOfFreeSlots() * bracket_size;
slot_addr = thread_local_run->AllocSlot();
// Must succeed now with a new run.
DCHECK(slot_addr != nullptr);
} else {
// The slot is already counted. Leave it as is.
*bytes_tl_bulk_allocated = 0;
}
DCHECK(slot_addr != nullptr);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocFromRun() thread-local : 0x" << std::hex
<< reinterpret_cast<intptr_t>(slot_addr)
<< "-0x" << (reinterpret_cast<intptr_t>(slot_addr) + bracket_size)
<< "(" << std::dec << (bracket_size) << ")";
}
*bytes_allocated = bracket_size;
*usable_size = bracket_size;
} else {
// Use the (shared) current run.
MutexLock mu(self, *size_bracket_locks_[idx]);
slot_addr = AllocFromCurrentRunUnlocked(self, idx);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::AllocFromRun() : 0x" << std::hex
<< reinterpret_cast<intptr_t>(slot_addr)
<< "-0x" << (reinterpret_cast<intptr_t>(slot_addr) + bracket_size)
<< "(" << std::dec << (bracket_size) << ")";
}
if (LIKELY(slot_addr != nullptr)) {
*bytes_allocated = bracket_size;
*usable_size = bracket_size;
*bytes_tl_bulk_allocated = bracket_size;
}
}
// Caller verifies that it is all 0.
return slot_addr;
}
size_t RosAlloc::FreeFromRun(Thread* self, void* ptr, Run* run) {
DCHECK_EQ(run->magic_num_, kMagicNum);
DCHECK_LT(run, ptr);
DCHECK_LT(ptr, run->End());
const size_t idx = run->size_bracket_idx_;
const size_t bracket_size = bracketSizes[idx];
bool run_was_full = false;
MutexLock brackets_mu(self, *size_bracket_locks_[idx]);
if (kIsDebugBuild) {
run_was_full = run->IsFull();
}
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreeFromRun() : 0x" << std::hex << reinterpret_cast<intptr_t>(ptr);
}
if (LIKELY(run->IsThreadLocal())) {
// It's a thread-local run. Just mark the thread-local free bit map and return.
DCHECK_LT(run->size_bracket_idx_, kNumThreadLocalSizeBrackets);
DCHECK(non_full_runs_[idx].find(run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(run) == full_runs_[idx].end());
run->MarkThreadLocalFreeBitMap(ptr);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreeFromRun() : Freed a slot in a thread local run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run);
}
// A thread local run will be kept as a thread local even if it's become all free.
return bracket_size;
}
// Free the slot in the run.
run->FreeSlot(ptr);
auto* non_full_runs = &non_full_runs_[idx];
if (run->IsAllFree()) {
// It has just become completely free. Free the pages of this run.
std::set<Run*>::iterator pos = non_full_runs->find(run);
if (pos != non_full_runs->end()) {
non_full_runs->erase(pos);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreeFromRun() : Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run) << " from non_full_runs_";
}
}
if (run == current_runs_[idx]) {
current_runs_[idx] = dedicated_full_run_;
}
DCHECK(non_full_runs_[idx].find(run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(run) == full_runs_[idx].end());
run->ZeroHeader();
{
MutexLock lock_mu(self, lock_);
FreePages(self, run, true);
}
} else {
// It is not completely free. If it wasn't the current run or
// already in the non-full run set (i.e., it was full) insert it
// into the non-full run set.
if (run != current_runs_[idx]) {
auto* full_runs = kIsDebugBuild ? &full_runs_[idx] : nullptr;
auto pos = non_full_runs->find(run);
if (pos == non_full_runs->end()) {
DCHECK(run_was_full);
DCHECK(full_runs->find(run) != full_runs->end());
if (kIsDebugBuild) {
full_runs->erase(run);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreeFromRun() : Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run) << " from full_runs_";
}
}
non_full_runs->insert(run);
DCHECK(!run->IsFull());
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::FreeFromRun() : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " into non_full_runs_[" << std::dec << idx << "]";
}
}
}
}
return bracket_size;
}
std::string RosAlloc::Run::BitMapToStr(uint32_t* bit_map_base, size_t num_vec) {
std::string bit_map_str;
for (size_t v = 0; v < num_vec; v++) {
uint32_t vec = bit_map_base[v];
if (v != num_vec - 1) {
bit_map_str.append(StringPrintf("%x-", vec));
} else {
bit_map_str.append(StringPrintf("%x", vec));
}
}
return bit_map_str.c_str();
}
std::string RosAlloc::Run::Dump() {
size_t idx = size_bracket_idx_;
size_t num_slots = numOfSlots[idx];
size_t num_vec = RoundUp(num_slots, 32) / 32;
std::ostringstream stream;
stream << "RosAlloc Run = " << reinterpret_cast<void*>(this)
<< "{ magic_num=" << static_cast<int>(magic_num_)
<< " size_bracket_idx=" << idx
<< " is_thread_local=" << static_cast<int>(is_thread_local_)
<< " to_be_bulk_freed=" << static_cast<int>(to_be_bulk_freed_)
<< " first_search_vec_idx=" << first_search_vec_idx_
<< " alloc_bit_map=" << BitMapToStr(alloc_bit_map_, num_vec)
<< " bulk_free_bit_map=" << BitMapToStr(BulkFreeBitMap(), num_vec)
<< " thread_local_bit_map=" << BitMapToStr(ThreadLocalFreeBitMap(), num_vec)
<< " }" << std::endl;
return stream.str();
}
void RosAlloc::Run::FreeSlot(void* ptr) {
DCHECK(!IsThreadLocal());
const uint8_t idx = size_bracket_idx_;
const size_t bracket_size = bracketSizes[idx];
const size_t offset_from_slot_base = reinterpret_cast<uint8_t*>(ptr)
- (reinterpret_cast<uint8_t*>(this) + headerSizes[idx]);
DCHECK_EQ(offset_from_slot_base % bracket_size, static_cast<size_t>(0));
size_t slot_idx = offset_from_slot_base / bracket_size;
DCHECK_LT(slot_idx, numOfSlots[idx]);
size_t vec_idx = slot_idx / 32;
if (kIsDebugBuild) {
size_t num_vec = RoundUp(numOfSlots[idx], 32) / 32;
DCHECK_LT(vec_idx, num_vec);
}
size_t vec_off = slot_idx % 32;
uint32_t* vec = &alloc_bit_map_[vec_idx];
first_search_vec_idx_ = std::min(first_search_vec_idx_, static_cast<uint32_t>(vec_idx));
const uint32_t mask = 1U << vec_off;
DCHECK_NE(*vec & mask, 0U);
*vec &= ~mask;
DCHECK_EQ(*vec & mask, 0U);
// Zero out the memory.
// TODO: Investigate alternate memset since ptr is guaranteed to be aligned to 16.
memset(ptr, 0, bracket_size);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::Run::FreeSlot() : 0x" << std::hex << reinterpret_cast<intptr_t>(ptr)
<< ", bracket_size=" << std::dec << bracketSizes[idx] << ", slot_idx=" << slot_idx;
}
}
size_t RosAlloc::Run::NumberOfFreeSlots() {
size_t num_alloc_slots = 0;
const size_t idx = size_bracket_idx_;
const size_t num_slots = numOfSlots[idx];
const size_t num_vec = RoundUp(num_slots, 32) / 32;
DCHECK_NE(num_vec, 0U);
for (size_t v = 0; v < num_vec - 1; v++) {
num_alloc_slots += POPCOUNT(alloc_bit_map_[v]);
}
// Don't count the invalid bits in the last vector.
uint32_t last_vec_masked = alloc_bit_map_[num_vec - 1] &
~GetBitmapLastVectorMask(num_slots, num_vec);
num_alloc_slots += POPCOUNT(last_vec_masked);
size_t num_free_slots = num_slots - num_alloc_slots;
DCHECK_LE(num_alloc_slots, num_slots);
DCHECK_LE(num_free_slots, num_slots);
return num_free_slots;
}
inline bool RosAlloc::Run::MergeThreadLocalFreeBitMapToAllocBitMap(bool* is_all_free_after_out) {
DCHECK(IsThreadLocal());
// Free slots in the alloc bit map based on the thread local free bit map.
const size_t idx = size_bracket_idx_;
const size_t num_of_slots = numOfSlots[idx];
const size_t num_vec = RoundUp(num_of_slots, 32) / 32;
bool changed = false;
uint32_t* vecp = &alloc_bit_map_[0];
uint32_t* tl_free_vecp = &ThreadLocalFreeBitMap()[0];
bool is_all_free_after = true;
for (size_t v = 0; v < num_vec; v++, vecp++, tl_free_vecp++) {
uint32_t tl_free_vec = *tl_free_vecp;
uint32_t vec_before = *vecp;
uint32_t vec_after;
if (tl_free_vec != 0) {
first_search_vec_idx_ = std::min(first_search_vec_idx_, static_cast<uint32_t>(v));
vec_after = vec_before & ~tl_free_vec;
*vecp = vec_after;
changed = true;
*tl_free_vecp = 0; // clear the thread local free bit map.
} else {
vec_after = vec_before;
}
if (vec_after != 0) {
if (v == num_vec - 1) {
// Only not all free if a bit other than the mask bits are set.
is_all_free_after =
is_all_free_after && GetBitmapLastVectorMask(num_of_slots, num_vec) == vec_after;
} else {
is_all_free_after = false;
}
}
DCHECK_EQ(*tl_free_vecp, static_cast<uint32_t>(0));
}
*is_all_free_after_out = is_all_free_after;
// Return true if there was at least a bit set in the thread-local
// free bit map and at least a bit in the alloc bit map changed.
return changed;
}
inline void RosAlloc::Run::MergeBulkFreeBitMapIntoAllocBitMap() {
DCHECK(!IsThreadLocal());
// Free slots in the alloc bit map based on the bulk free bit map.
const size_t num_vec = NumberOfBitmapVectors();
uint32_t* vecp = &alloc_bit_map_[0];
uint32_t* free_vecp = &BulkFreeBitMap()[0];
for (size_t v = 0; v < num_vec; v++, vecp++, free_vecp++) {
uint32_t free_vec = *free_vecp;
if (free_vec != 0) {
first_search_vec_idx_ = std::min(first_search_vec_idx_, static_cast<uint32_t>(v));
*vecp &= ~free_vec;
*free_vecp = 0; // clear the bulk free bit map.
}
DCHECK_EQ(*free_vecp, static_cast<uint32_t>(0));
}
}
inline void RosAlloc::Run::UnionBulkFreeBitMapToThreadLocalFreeBitMap() {
DCHECK(IsThreadLocal());
// Union the thread local bit map with the bulk free bit map.
size_t num_vec = NumberOfBitmapVectors();
uint32_t* to_vecp = &ThreadLocalFreeBitMap()[0];
uint32_t* from_vecp = &BulkFreeBitMap()[0];
for (size_t v = 0; v < num_vec; v++, to_vecp++, from_vecp++) {
uint32_t from_vec = *from_vecp;
if (from_vec != 0) {
*to_vecp |= from_vec;
*from_vecp = 0; // clear the bulk free bit map.
}
DCHECK_EQ(*from_vecp, static_cast<uint32_t>(0));
}
}
inline void RosAlloc::Run::MarkThreadLocalFreeBitMap(void* ptr) {
DCHECK(IsThreadLocal());
MarkFreeBitMapShared(ptr, ThreadLocalFreeBitMap(), "MarkThreadLocalFreeBitMap");
}
inline size_t RosAlloc::Run::MarkBulkFreeBitMap(void* ptr) {
return MarkFreeBitMapShared(ptr, BulkFreeBitMap(), "MarkFreeBitMap");
}
inline size_t RosAlloc::Run::MarkFreeBitMapShared(void* ptr, uint32_t* free_bit_map_base,
const char* caller_name) {
const uint8_t idx = size_bracket_idx_;
const size_t offset_from_slot_base = reinterpret_cast<uint8_t*>(ptr)
- (reinterpret_cast<uint8_t*>(this) + headerSizes[idx]);
const size_t bracket_size = bracketSizes[idx];
memset(ptr, 0, bracket_size);
DCHECK_EQ(offset_from_slot_base % bracket_size, static_cast<size_t>(0));
size_t slot_idx = offset_from_slot_base / bracket_size;
DCHECK_LT(slot_idx, numOfSlots[idx]);
size_t vec_idx = slot_idx / 32;
if (kIsDebugBuild) {
size_t num_vec = NumberOfBitmapVectors();
DCHECK_LT(vec_idx, num_vec);
}
size_t vec_off = slot_idx % 32;
uint32_t* vec = &free_bit_map_base[vec_idx];
const uint32_t mask = 1U << vec_off;
DCHECK_EQ(*vec & mask, 0U);
*vec |= mask;
DCHECK_NE(*vec & mask, 0U);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::Run::" << caller_name << "() : 0x" << std::hex
<< reinterpret_cast<intptr_t>(ptr)
<< ", bracket_size=" << std::dec << bracketSizes[idx] << ", slot_idx=" << slot_idx;
}
return bracket_size;
}
inline uint32_t RosAlloc::Run::GetBitmapLastVectorMask(size_t num_slots, size_t num_vec) {
const size_t kBitsPerVec = 32;
DCHECK_GE(num_vec * kBitsPerVec, num_slots);
DCHECK_NE(num_vec, 0U);
size_t remain = num_vec * kBitsPerVec - num_slots;
DCHECK_LT(remain, kBitsPerVec);
return ((1U << remain) - 1) << ((kBitsPerVec - remain) & 0x1F);
}
inline bool RosAlloc::Run::IsAllFree() {
const uint8_t idx = size_bracket_idx_;
const size_t num_slots = numOfSlots[idx];
const size_t num_vec = NumberOfBitmapVectors();
DCHECK_NE(num_vec, 0U);
// Check the last vector after the loop since it uses a special case for the masked bits.
for (size_t v = 0; v < num_vec - 1; v++) {
uint32_t vec = alloc_bit_map_[v];
if (vec != 0) {
return false;
}
}
// Make sure the last word is equal to the mask, all other bits must be 0.
return alloc_bit_map_[num_vec - 1] == GetBitmapLastVectorMask(num_slots, num_vec);
}
inline bool RosAlloc::Run::IsBulkFreeBitmapClean() {
const size_t num_vec = NumberOfBitmapVectors();
for (size_t v = 0; v < num_vec; v++) {
uint32_t vec = BulkFreeBitMap()[v];
if (vec != 0) {
return false;
}
}
return true;
}
inline bool RosAlloc::Run::IsThreadLocalFreeBitmapClean() {
const size_t num_vec = NumberOfBitmapVectors();
for (size_t v = 0; v < num_vec; v++) {
uint32_t vec = ThreadLocalFreeBitMap()[v];
if (vec != 0) {
return false;
}
}
return true;
}
inline void RosAlloc::Run::SetAllocBitMapBitsForInvalidSlots() {
const size_t idx = size_bracket_idx_;
const size_t num_slots = numOfSlots[idx];
const size_t num_vec = RoundUp(num_slots, 32) / 32;
DCHECK_NE(num_vec, 0U);
// Make sure to set the bits at the end of the bitmap so that we don't allocate there since they
// don't represent valid slots.
alloc_bit_map_[num_vec - 1] |= GetBitmapLastVectorMask(num_slots, num_vec);
}
inline void RosAlloc::Run::ZeroHeader() {
const uint8_t idx = size_bracket_idx_;
memset(this, 0, headerSizes[idx]);
}
inline void RosAlloc::Run::ZeroData() {
const uint8_t idx = size_bracket_idx_;
uint8_t* slot_begin = reinterpret_cast<uint8_t*>(this) + headerSizes[idx];
memset(slot_begin, 0, numOfSlots[idx] * bracketSizes[idx]);
}
inline void RosAlloc::Run::FillAllocBitMap() {
size_t num_vec = NumberOfBitmapVectors();
memset(alloc_bit_map_, 0xFF, sizeof(uint32_t) * num_vec);
first_search_vec_idx_ = num_vec - 1; // No free bits in any of the bitmap words.
}
void RosAlloc::Run::InspectAllSlots(void (*handler)(void* start, void* end, size_t used_bytes, void* callback_arg),
void* arg) {
size_t idx = size_bracket_idx_;
uint8_t* slot_base = reinterpret_cast<uint8_t*>(this) + headerSizes[idx];
size_t num_slots = numOfSlots[idx];
size_t bracket_size = IndexToBracketSize(idx);
DCHECK_EQ(slot_base + num_slots * bracket_size,
reinterpret_cast<uint8_t*>(this) + numOfPages[idx] * kPageSize);
size_t num_vec = RoundUp(num_slots, 32) / 32;
size_t slots = 0;
const uint32_t* const tl_free_vecp = IsThreadLocal() ? ThreadLocalFreeBitMap() : nullptr;
for (size_t v = 0; v < num_vec; v++, slots += 32) {
DCHECK_GE(num_slots, slots);
uint32_t vec = alloc_bit_map_[v];
if (tl_free_vecp != nullptr) {
// Clear out the set bits in the thread local free bitmap since these aren't actually
// allocated.
vec &= ~tl_free_vecp[v];
}
size_t end = std::min(num_slots - slots, static_cast<size_t>(32));
for (size_t i = 0; i < end; ++i) {
bool is_allocated = ((vec >> i) & 0x1) != 0;
uint8_t* slot_addr = slot_base + (slots + i) * bracket_size;
if (is_allocated) {
handler(slot_addr, slot_addr + bracket_size, bracket_size, arg);
} else {
handler(slot_addr, slot_addr + bracket_size, 0, arg);
}
}
}
}
// If true, read the page map entries in BulkFree() without using the
// lock for better performance, assuming that the existence of an
// allocated chunk/pointer being freed in BulkFree() guarantees that
// the page map entry won't change. Disabled for now.
static constexpr bool kReadPageMapEntryWithoutLockInBulkFree = true;
size_t RosAlloc::BulkFree(Thread* self, void** ptrs, size_t num_ptrs) {
size_t freed_bytes = 0;
if ((false)) {
// Used only to test Free() as GC uses only BulkFree().
for (size_t i = 0; i < num_ptrs; ++i) {
freed_bytes += FreeInternal(self, ptrs[i]);
}
return freed_bytes;
}
WriterMutexLock wmu(self, bulk_free_lock_);
// First mark slots to free in the bulk free bit map without locking the
// size bracket locks. On host, unordered_set is faster than vector + flag.
#ifdef HAVE_ANDROID_OS
std::vector<Run*> runs;
#else
std::unordered_set<Run*, hash_run, eq_run> runs;
#endif
for (size_t i = 0; i < num_ptrs; i++) {
void* ptr = ptrs[i];
DCHECK_LE(base_, ptr);
DCHECK_LT(ptr, base_ + footprint_);
size_t pm_idx = RoundDownToPageMapIndex(ptr);
Run* run = nullptr;
if (kReadPageMapEntryWithoutLockInBulkFree) {
// Read the page map entries without locking the lock.
uint8_t page_map_entry = page_map_[pm_idx];
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : " << std::hex << ptr << ", pm_idx="
<< std::dec << pm_idx
<< ", page_map_entry=" << static_cast<int>(page_map_entry);
}
if (LIKELY(page_map_entry == kPageMapRun)) {
run = reinterpret_cast<Run*>(base_ + pm_idx * kPageSize);
} else if (LIKELY(page_map_entry == kPageMapRunPart)) {
size_t pi = pm_idx;
// Find the beginning of the run.
do {
--pi;
DCHECK_LT(pi, capacity_ / kPageSize);
} while (page_map_[pi] != kPageMapRun);
run = reinterpret_cast<Run*>(base_ + pi * kPageSize);
} else if (page_map_entry == kPageMapLargeObject) {
MutexLock mu(self, lock_);
freed_bytes += FreePages(self, ptr, false);
continue;
} else {
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_entry);
}
} else {
// Read the page map entries with a lock.
MutexLock mu(self, lock_);
DCHECK_LT(pm_idx, page_map_size_);
uint8_t page_map_entry = page_map_[pm_idx];
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : " << std::hex << ptr << ", pm_idx="
<< std::dec << pm_idx
<< ", page_map_entry=" << static_cast<int>(page_map_entry);
}
if (LIKELY(page_map_entry == kPageMapRun)) {
run = reinterpret_cast<Run*>(base_ + pm_idx * kPageSize);
} else if (LIKELY(page_map_entry == kPageMapRunPart)) {
size_t pi = pm_idx;
// Find the beginning of the run.
do {
--pi;
DCHECK_LT(pi, capacity_ / kPageSize);
} while (page_map_[pi] != kPageMapRun);
run = reinterpret_cast<Run*>(base_ + pi * kPageSize);
} else if (page_map_entry == kPageMapLargeObject) {
freed_bytes += FreePages(self, ptr, false);
continue;
} else {
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_entry);
}
}
DCHECK(run != nullptr);
DCHECK_EQ(run->magic_num_, kMagicNum);
// Set the bit in the bulk free bit map.
freed_bytes += run->MarkBulkFreeBitMap(ptr);
#ifdef HAVE_ANDROID_OS
if (!run->to_be_bulk_freed_) {
run->to_be_bulk_freed_ = true;
runs.push_back(run);
}
#else
runs.insert(run);
#endif
}
// Now, iterate over the affected runs and update the alloc bit map
// based on the bulk free bit map (for non-thread-local runs) and
// union the bulk free bit map into the thread-local free bit map
// (for thread-local runs.)
for (Run* run : runs) {
#ifdef HAVE_ANDROID_OS
DCHECK(run->to_be_bulk_freed_);
run->to_be_bulk_freed_ = false;
#endif
size_t idx = run->size_bracket_idx_;
MutexLock brackets_mu(self, *size_bracket_locks_[idx]);
if (run->IsThreadLocal()) {
DCHECK_LT(run->size_bracket_idx_, kNumThreadLocalSizeBrackets);
DCHECK(non_full_runs_[idx].find(run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(run) == full_runs_[idx].end());
run->UnionBulkFreeBitMapToThreadLocalFreeBitMap();
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : Freed slot(s) in a thread local run 0x"
<< std::hex << reinterpret_cast<intptr_t>(run);
}
DCHECK(run->IsThreadLocal());
// A thread local run will be kept as a thread local even if
// it's become all free.
} else {
bool run_was_full = run->IsFull();
run->MergeBulkFreeBitMapIntoAllocBitMap();
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : Freed slot(s) in a run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run);
}
// Check if the run should be moved to non_full_runs_ or
// free_page_runs_.
auto* non_full_runs = &non_full_runs_[idx];
auto* full_runs = kIsDebugBuild ? &full_runs_[idx] : nullptr;
if (run->IsAllFree()) {
// It has just become completely free. Free the pages of the
// run.
bool run_was_current = run == current_runs_[idx];
if (run_was_current) {
DCHECK(full_runs->find(run) == full_runs->end());
DCHECK(non_full_runs->find(run) == non_full_runs->end());
// If it was a current run, reuse it.
} else if (run_was_full) {
// If it was full, remove it from the full run set (debug
// only.)
if (kIsDebugBuild) {
std::unordered_set<Run*, hash_run, eq_run>::iterator pos = full_runs->find(run);
DCHECK(pos != full_runs->end());
full_runs->erase(pos);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " from full_runs_";
}
DCHECK(full_runs->find(run) == full_runs->end());
}
} else {
// If it was in a non full run set, remove it from the set.
DCHECK(full_runs->find(run) == full_runs->end());
DCHECK(non_full_runs->find(run) != non_full_runs->end());
non_full_runs->erase(run);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " from non_full_runs_";
}
DCHECK(non_full_runs->find(run) == non_full_runs->end());
}
if (!run_was_current) {
run->ZeroHeader();
MutexLock lock_mu(self, lock_);
FreePages(self, run, true);
}
} else {
// It is not completely free. If it wasn't the current run or
// already in the non-full run set (i.e., it was full) insert
// it into the non-full run set.
if (run == current_runs_[idx]) {
DCHECK(non_full_runs->find(run) == non_full_runs->end());
DCHECK(full_runs->find(run) == full_runs->end());
// If it was a current run, keep it.
} else if (run_was_full) {
// If it was full, remove it from the full run set (debug
// only) and insert into the non-full run set.
DCHECK(full_runs->find(run) != full_runs->end());
DCHECK(non_full_runs->find(run) == non_full_runs->end());
if (kIsDebugBuild) {
full_runs->erase(run);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : Erased run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " from full_runs_";
}
}
non_full_runs->insert(run);
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::BulkFree() : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " into non_full_runs_[" << std::dec << idx;
}
} else {
// If it was not full, so leave it in the non full run set.
DCHECK(full_runs->find(run) == full_runs->end());
DCHECK(non_full_runs->find(run) != non_full_runs->end());
}
}
}
}
return freed_bytes;
}
std::string RosAlloc::DumpPageMap() {
std::ostringstream stream;
stream << "RosAlloc PageMap: " << std::endl;
lock_.AssertHeld(Thread::Current());
size_t end = page_map_size_;
FreePageRun* curr_fpr = nullptr;
size_t curr_fpr_size = 0;
size_t remaining_curr_fpr_size = 0;
size_t num_running_empty_pages = 0;
for (size_t i = 0; i < end; ++i) {
uint8_t pm = page_map_[i];
switch (pm) {
case kPageMapReleased:
// Fall-through.
case kPageMapEmpty: {
FreePageRun* fpr = reinterpret_cast<FreePageRun*>(base_ + i * kPageSize);
if (free_page_runs_.find(fpr) != free_page_runs_.end()) {
// Encountered a fresh free page run.
DCHECK_EQ(remaining_curr_fpr_size, static_cast<size_t>(0));
DCHECK(fpr->IsFree());
DCHECK(curr_fpr == nullptr);
DCHECK_EQ(curr_fpr_size, static_cast<size_t>(0));
curr_fpr = fpr;
curr_fpr_size = fpr->ByteSize(this);
DCHECK_EQ(curr_fpr_size % kPageSize, static_cast<size_t>(0));
remaining_curr_fpr_size = curr_fpr_size - kPageSize;
stream << "[" << i << "]=" << (pm == kPageMapReleased ? "Released" : "Empty")
<< " (FPR start) fpr_size=" << curr_fpr_size
<< " remaining_fpr_size=" << remaining_curr_fpr_size << std::endl;
if (remaining_curr_fpr_size == 0) {
// Reset at the end of the current free page run.
curr_fpr = nullptr;
curr_fpr_size = 0;
}
stream << "curr_fpr=0x" << std::hex << reinterpret_cast<intptr_t>(curr_fpr) << std::endl;
DCHECK_EQ(num_running_empty_pages, static_cast<size_t>(0));
} else {
// Still part of the current free page run.
DCHECK_NE(num_running_empty_pages, static_cast<size_t>(0));
DCHECK(curr_fpr != nullptr && curr_fpr_size > 0 && remaining_curr_fpr_size > 0);
DCHECK_EQ(remaining_curr_fpr_size % kPageSize, static_cast<size_t>(0));
DCHECK_GE(remaining_curr_fpr_size, static_cast<size_t>(kPageSize));
remaining_curr_fpr_size -= kPageSize;
stream << "[" << i << "]=Empty (FPR part)"
<< " remaining_fpr_size=" << remaining_curr_fpr_size << std::endl;
if (remaining_curr_fpr_size == 0) {
// Reset at the end of the current free page run.
curr_fpr = nullptr;
curr_fpr_size = 0;
}
}
num_running_empty_pages++;
break;
}
case kPageMapLargeObject: {
DCHECK_EQ(remaining_curr_fpr_size, static_cast<size_t>(0));
num_running_empty_pages = 0;
stream << "[" << i << "]=Large (start)" << std::endl;
break;
}
case kPageMapLargeObjectPart:
DCHECK_EQ(remaining_curr_fpr_size, static_cast<size_t>(0));
num_running_empty_pages = 0;
stream << "[" << i << "]=Large (part)" << std::endl;
break;
case kPageMapRun: {
DCHECK_EQ(remaining_curr_fpr_size, static_cast<size_t>(0));
num_running_empty_pages = 0;
Run* run = reinterpret_cast<Run*>(base_ + i * kPageSize);
size_t idx = run->size_bracket_idx_;
stream << "[" << i << "]=Run (start)"
<< " idx=" << idx
<< " numOfPages=" << numOfPages[idx]
<< " is_thread_local=" << run->is_thread_local_
<< " is_all_free=" << (run->IsAllFree() ? 1 : 0)
<< std::endl;
break;
}
case kPageMapRunPart:
DCHECK_EQ(remaining_curr_fpr_size, static_cast<size_t>(0));
num_running_empty_pages = 0;
stream << "[" << i << "]=Run (part)" << std::endl;
break;
default:
stream << "[" << i << "]=Unrecognizable page map type: " << pm;
break;
}
}
return stream.str();
}
size_t RosAlloc::UsableSize(const void* ptr) {
DCHECK_LE(base_, ptr);
DCHECK_LT(ptr, base_ + footprint_);
size_t pm_idx = RoundDownToPageMapIndex(ptr);
MutexLock mu(Thread::Current(), lock_);
switch (page_map_[pm_idx]) {
case kPageMapReleased:
// Fall-through.
case kPageMapEmpty:
LOG(FATAL) << "Unreachable - " << __PRETTY_FUNCTION__ << ": pm_idx=" << pm_idx << ", ptr="
<< std::hex << reinterpret_cast<intptr_t>(ptr);
break;
case kPageMapLargeObject: {
size_t num_pages = 1;
size_t idx = pm_idx + 1;
size_t end = page_map_size_;
while (idx < end && page_map_[idx] == kPageMapLargeObjectPart) {
num_pages++;
idx++;
}
return num_pages * kPageSize;
}
case kPageMapLargeObjectPart:
LOG(FATAL) << "Unreachable - " << __PRETTY_FUNCTION__ << ": pm_idx=" << pm_idx << ", ptr="
<< std::hex << reinterpret_cast<intptr_t>(ptr);
break;
case kPageMapRun:
case kPageMapRunPart: {
// Find the beginning of the run.
while (page_map_[pm_idx] != kPageMapRun) {
pm_idx--;
DCHECK_LT(pm_idx, capacity_ / kPageSize);
}
DCHECK_EQ(page_map_[pm_idx], kPageMapRun);
Run* run = reinterpret_cast<Run*>(base_ + pm_idx * kPageSize);
DCHECK_EQ(run->magic_num_, kMagicNum);
size_t idx = run->size_bracket_idx_;
size_t offset_from_slot_base = reinterpret_cast<const uint8_t*>(ptr)
- (reinterpret_cast<uint8_t*>(run) + headerSizes[idx]);
DCHECK_EQ(offset_from_slot_base % bracketSizes[idx], static_cast<size_t>(0));
return IndexToBracketSize(idx);
}
default: {
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(page_map_[pm_idx]);
break;
}
}
return 0;
}
bool RosAlloc::Trim() {
MutexLock mu(Thread::Current(), lock_);
FreePageRun* last_free_page_run;
DCHECK_EQ(footprint_ % kPageSize, static_cast<size_t>(0));
auto it = free_page_runs_.rbegin();
if (it != free_page_runs_.rend() && (last_free_page_run = *it)->End(this) == base_ + footprint_) {
// Remove the last free page run, if any.
DCHECK(last_free_page_run->IsFree());
DCHECK(IsFreePage(ToPageMapIndex(last_free_page_run)));
DCHECK_EQ(last_free_page_run->ByteSize(this) % kPageSize, static_cast<size_t>(0));
DCHECK_EQ(last_free_page_run->End(this), base_ + footprint_);
free_page_runs_.erase(last_free_page_run);
size_t decrement = last_free_page_run->ByteSize(this);
size_t new_footprint = footprint_ - decrement;
DCHECK_EQ(new_footprint % kPageSize, static_cast<size_t>(0));
size_t new_num_of_pages = new_footprint / kPageSize;
DCHECK_GE(page_map_size_, new_num_of_pages);
// Zero out the tail of the page map.
uint8_t* zero_begin = const_cast<uint8_t*>(page_map_) + new_num_of_pages;
uint8_t* madvise_begin = AlignUp(zero_begin, kPageSize);
DCHECK_LE(madvise_begin, page_map_mem_map_->End());
size_t madvise_size = page_map_mem_map_->End() - madvise_begin;
if (madvise_size > 0) {
DCHECK_ALIGNED(madvise_begin, kPageSize);
DCHECK_EQ(RoundUp(madvise_size, kPageSize), madvise_size);
if (!kMadviseZeroes) {
memset(madvise_begin, 0, madvise_size);
}
CHECK_EQ(madvise(madvise_begin, madvise_size, MADV_DONTNEED), 0);
}
if (madvise_begin - zero_begin) {
memset(zero_begin, 0, madvise_begin - zero_begin);
}
page_map_size_ = new_num_of_pages;
free_page_run_size_map_.resize(new_num_of_pages);
DCHECK_EQ(free_page_run_size_map_.size(), new_num_of_pages);
ArtRosAllocMoreCore(this, -(static_cast<intptr_t>(decrement)));
if (kTraceRosAlloc) {
LOG(INFO) << "RosAlloc::Trim() : decreased the footprint from "
<< footprint_ << " to " << new_footprint;
}
DCHECK_LT(new_footprint, footprint_);
DCHECK_LT(new_footprint, capacity_);
footprint_ = new_footprint;
return true;
}
return false;
}
void RosAlloc::InspectAll(void (*handler)(void* start, void* end, size_t used_bytes, void* callback_arg),
void* arg) {
// Note: no need to use this to release pages as we already do so in FreePages().
if (handler == nullptr) {
return;
}
MutexLock mu(Thread::Current(), lock_);
size_t pm_end = page_map_size_;
size_t i = 0;
while (i < pm_end) {
uint8_t pm = page_map_[i];
switch (pm) {
case kPageMapReleased:
// Fall-through.
case kPageMapEmpty: {
// The start of a free page run.
FreePageRun* fpr = reinterpret_cast<FreePageRun*>(base_ + i * kPageSize);
DCHECK(free_page_runs_.find(fpr) != free_page_runs_.end());
size_t fpr_size = fpr->ByteSize(this);
DCHECK(IsAligned<kPageSize>(fpr_size));
void* start = fpr;
if (kIsDebugBuild) {
// In the debug build, the first page of a free page run
// contains a magic number for debugging. Exclude it.
start = reinterpret_cast<uint8_t*>(fpr) + kPageSize;
}
void* end = reinterpret_cast<uint8_t*>(fpr) + fpr_size;
handler(start, end, 0, arg);
size_t num_pages = fpr_size / kPageSize;
if (kIsDebugBuild) {
for (size_t j = i + 1; j < i + num_pages; ++j) {
DCHECK(IsFreePage(j));
}
}
i += fpr_size / kPageSize;
DCHECK_LE(i, pm_end);
break;
}
case kPageMapLargeObject: {
// The start of a large object.
size_t num_pages = 1;
size_t idx = i + 1;
while (idx < pm_end && page_map_[idx] == kPageMapLargeObjectPart) {
num_pages++;
idx++;
}
void* start = base_ + i * kPageSize;
void* end = base_ + (i + num_pages) * kPageSize;
size_t used_bytes = num_pages * kPageSize;
handler(start, end, used_bytes, arg);
if (kIsDebugBuild) {
for (size_t j = i + 1; j < i + num_pages; ++j) {
DCHECK_EQ(page_map_[j], kPageMapLargeObjectPart);
}
}
i += num_pages;
DCHECK_LE(i, pm_end);
break;
}
case kPageMapLargeObjectPart:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(pm);
break;
case kPageMapRun: {
// The start of a run.
Run* run = reinterpret_cast<Run*>(base_ + i * kPageSize);
DCHECK_EQ(run->magic_num_, kMagicNum);
// The dedicated full run doesn't contain any real allocations, don't visit the slots in
// there.
run->InspectAllSlots(handler, arg);
size_t num_pages = numOfPages[run->size_bracket_idx_];
if (kIsDebugBuild) {
for (size_t j = i + 1; j < i + num_pages; ++j) {
DCHECK_EQ(page_map_[j], kPageMapRunPart);
}
}
i += num_pages;
DCHECK_LE(i, pm_end);
break;
}
case kPageMapRunPart:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(pm);
break;
default:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(pm);
break;
}
}
}
size_t RosAlloc::Footprint() {
MutexLock mu(Thread::Current(), lock_);
return footprint_;
}
size_t RosAlloc::FootprintLimit() {
MutexLock mu(Thread::Current(), lock_);
return capacity_;
}
void RosAlloc::SetFootprintLimit(size_t new_capacity) {
MutexLock mu(Thread::Current(), lock_);
DCHECK_EQ(RoundUp(new_capacity, kPageSize), new_capacity);
// Only growing is supported here. But Trim() is supported.
if (capacity_ < new_capacity) {
CHECK_LE(new_capacity, max_capacity_);
capacity_ = new_capacity;
VLOG(heap) << "new capacity=" << capacity_;
}
}
size_t RosAlloc::RevokeThreadLocalRuns(Thread* thread) {
Thread* self = Thread::Current();
// Avoid race conditions on the bulk free bit maps with BulkFree() (GC).
ReaderMutexLock wmu(self, bulk_free_lock_);
size_t free_bytes = 0U;
for (size_t idx = 0; idx < kNumThreadLocalSizeBrackets; idx++) {
MutexLock mu(self, *size_bracket_locks_[idx]);
Run* thread_local_run = reinterpret_cast<Run*>(thread->GetRosAllocRun(idx));
CHECK(thread_local_run != nullptr);
// Invalid means already revoked.
DCHECK(thread_local_run->IsThreadLocal());
if (thread_local_run != dedicated_full_run_) {
// Note the thread local run may not be full here.
thread->SetRosAllocRun(idx, dedicated_full_run_);
DCHECK_EQ(thread_local_run->magic_num_, kMagicNum);
// Count the number of free slots left.
size_t num_free_slots = thread_local_run->NumberOfFreeSlots();
free_bytes += num_free_slots * bracketSizes[idx];
bool dont_care;
thread_local_run->MergeThreadLocalFreeBitMapToAllocBitMap(&dont_care);
thread_local_run->SetIsThreadLocal(false);
thread_local_run->MergeBulkFreeBitMapIntoAllocBitMap();
DCHECK(non_full_runs_[idx].find(thread_local_run) == non_full_runs_[idx].end());
DCHECK(full_runs_[idx].find(thread_local_run) == full_runs_[idx].end());
RevokeRun(self, idx, thread_local_run);
}
}
return free_bytes;
}
void RosAlloc::RevokeRun(Thread* self, size_t idx, Run* run) {
size_bracket_locks_[idx]->AssertHeld(self);
DCHECK(run != dedicated_full_run_);
if (run->IsFull()) {
if (kIsDebugBuild) {
full_runs_[idx].insert(run);
DCHECK(full_runs_[idx].find(run) != full_runs_[idx].end());
if (kTraceRosAlloc) {
LOG(INFO) << __PRETTY_FUNCTION__ << " : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " into full_runs_[" << std::dec << idx << "]";
}
}
} else if (run->IsAllFree()) {
run->ZeroHeader();
MutexLock mu(self, lock_);
FreePages(self, run, true);
} else {
non_full_runs_[idx].insert(run);
DCHECK(non_full_runs_[idx].find(run) != non_full_runs_[idx].end());
if (kTraceRosAlloc) {
LOG(INFO) << __PRETTY_FUNCTION__ << " : Inserted run 0x" << std::hex
<< reinterpret_cast<intptr_t>(run)
<< " into non_full_runs_[" << std::dec << idx << "]";
}
}
}
void RosAlloc::RevokeThreadUnsafeCurrentRuns() {
// Revoke the current runs which share the same idx as thread local runs.
Thread* self = Thread::Current();
for (size_t idx = 0; idx < kNumThreadLocalSizeBrackets; ++idx) {
MutexLock mu(self, *size_bracket_locks_[idx]);
if (current_runs_[idx] != dedicated_full_run_) {
RevokeRun(self, idx, current_runs_[idx]);
current_runs_[idx] = dedicated_full_run_;
}
}
}
size_t RosAlloc::RevokeAllThreadLocalRuns() {
// This is called when a mutator thread won't allocate such as at
// the Zygote creation time or during the GC pause.
MutexLock mu(Thread::Current(), *Locks::runtime_shutdown_lock_);
MutexLock mu2(Thread::Current(), *Locks::thread_list_lock_);
std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList();
size_t free_bytes = 0U;
for (Thread* thread : thread_list) {
free_bytes += RevokeThreadLocalRuns(thread);
}
RevokeThreadUnsafeCurrentRuns();
return free_bytes;
}
void RosAlloc::AssertThreadLocalRunsAreRevoked(Thread* thread) {
if (kIsDebugBuild) {
Thread* self = Thread::Current();
// Avoid race conditions on the bulk free bit maps with BulkFree() (GC).
ReaderMutexLock wmu(self, bulk_free_lock_);
for (size_t idx = 0; idx < kNumThreadLocalSizeBrackets; idx++) {
MutexLock mu(self, *size_bracket_locks_[idx]);
Run* thread_local_run = reinterpret_cast<Run*>(thread->GetRosAllocRun(idx));
DCHECK(thread_local_run == nullptr || thread_local_run == dedicated_full_run_);
}
}
}
void RosAlloc::AssertAllThreadLocalRunsAreRevoked() {
if (kIsDebugBuild) {
Thread* self = Thread::Current();
MutexLock shutdown_mu(self, *Locks::runtime_shutdown_lock_);
MutexLock thread_list_mu(self, *Locks::thread_list_lock_);
std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList();
for (Thread* t : thread_list) {
AssertThreadLocalRunsAreRevoked(t);
}
for (size_t idx = 0; idx < kNumThreadLocalSizeBrackets; ++idx) {
MutexLock brackets_mu(self, *size_bracket_locks_[idx]);
CHECK_EQ(current_runs_[idx], dedicated_full_run_);
}
}
}
void RosAlloc::Initialize() {
// bracketSizes.
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
if (i < kNumOfSizeBrackets - 2) {
bracketSizes[i] = 16 * (i + 1);
} else if (i == kNumOfSizeBrackets - 2) {
bracketSizes[i] = 1 * KB;
} else {
DCHECK_EQ(i, kNumOfSizeBrackets - 1);
bracketSizes[i] = 2 * KB;
}
if (kTraceRosAlloc) {
LOG(INFO) << "bracketSizes[" << i << "]=" << bracketSizes[i];
}
}
// numOfPages.
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
if (i < 4) {
numOfPages[i] = 1;
} else if (i < 8) {
numOfPages[i] = 1;
} else if (i < 16) {
numOfPages[i] = 4;
} else if (i < 32) {
numOfPages[i] = 8;
} else if (i == 32) {
DCHECK_EQ(i, kNumOfSizeBrackets - 2);
numOfPages[i] = 16;
} else {
DCHECK_EQ(i, kNumOfSizeBrackets - 1);
numOfPages[i] = 32;
}
if (kTraceRosAlloc) {
LOG(INFO) << "numOfPages[" << i << "]=" << numOfPages[i];
}
}
// Compute numOfSlots and slotOffsets.
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
size_t bracket_size = bracketSizes[i];
size_t run_size = kPageSize * numOfPages[i];
size_t max_num_of_slots = run_size / bracket_size;
// Compute the actual number of slots by taking the header and
// alignment into account.
size_t fixed_header_size = RoundUp(Run::fixed_header_size(), sizeof(uint32_t));
DCHECK_EQ(fixed_header_size, static_cast<size_t>(8));
size_t header_size = 0;
size_t bulk_free_bit_map_offset = 0;
size_t thread_local_free_bit_map_offset = 0;
size_t num_of_slots = 0;
// Search for the maximum number of slots that allows enough space
// for the header (including the bit maps.)
for (int s = max_num_of_slots; s >= 0; s--) {
size_t tmp_slots_size = bracket_size * s;
size_t tmp_bit_map_size = RoundUp(s, sizeof(uint32_t) * kBitsPerByte) / kBitsPerByte;
size_t tmp_bulk_free_bit_map_size = tmp_bit_map_size;
size_t tmp_bulk_free_bit_map_off = fixed_header_size + tmp_bit_map_size;
size_t tmp_thread_local_free_bit_map_size = tmp_bit_map_size;
size_t tmp_thread_local_free_bit_map_off = tmp_bulk_free_bit_map_off + tmp_bulk_free_bit_map_size;
size_t tmp_unaligned_header_size = tmp_thread_local_free_bit_map_off + tmp_thread_local_free_bit_map_size;
// Align up the unaligned header size. bracket_size may not be a power of two.
size_t tmp_header_size = (tmp_unaligned_header_size % bracket_size == 0) ?
tmp_unaligned_header_size :
tmp_unaligned_header_size + (bracket_size - tmp_unaligned_header_size % bracket_size);
DCHECK_EQ(tmp_header_size % bracket_size, static_cast<size_t>(0));
DCHECK_EQ(tmp_header_size % 8, static_cast<size_t>(0));
if (tmp_slots_size + tmp_header_size <= run_size) {
// Found the right number of slots, that is, there was enough
// space for the header (including the bit maps.)
num_of_slots = s;
header_size = tmp_header_size;
bulk_free_bit_map_offset = tmp_bulk_free_bit_map_off;
thread_local_free_bit_map_offset = tmp_thread_local_free_bit_map_off;
break;
}
}
DCHECK(num_of_slots > 0 && header_size > 0 && bulk_free_bit_map_offset > 0);
// Add the padding for the alignment remainder.
header_size += run_size % bracket_size;
DCHECK_EQ(header_size + num_of_slots * bracket_size, run_size);
numOfSlots[i] = num_of_slots;
headerSizes[i] = header_size;
bulkFreeBitMapOffsets[i] = bulk_free_bit_map_offset;
threadLocalFreeBitMapOffsets[i] = thread_local_free_bit_map_offset;
if (kTraceRosAlloc) {
LOG(INFO) << "numOfSlots[" << i << "]=" << numOfSlots[i]
<< ", headerSizes[" << i << "]=" << headerSizes[i]
<< ", bulkFreeBitMapOffsets[" << i << "]=" << bulkFreeBitMapOffsets[i]
<< ", threadLocalFreeBitMapOffsets[" << i << "]=" << threadLocalFreeBitMapOffsets[i];;
}
}
// Fill the alloc bitmap so nobody can successfully allocate from it.
if (kIsDebugBuild) {
dedicated_full_run_->magic_num_ = kMagicNum;
}
// It doesn't matter which size bracket we use since the main goal is to have the allocation
// fail 100% of the time you attempt to allocate into the dedicated full run.
dedicated_full_run_->size_bracket_idx_ = 0;
dedicated_full_run_->FillAllocBitMap();
dedicated_full_run_->SetIsThreadLocal(true);
}
void RosAlloc::BytesAllocatedCallback(void* start ATTRIBUTE_UNUSED, void* end ATTRIBUTE_UNUSED,
size_t used_bytes, void* arg) {
if (used_bytes == 0) {
return;
}
size_t* bytes_allocated = reinterpret_cast<size_t*>(arg);
*bytes_allocated += used_bytes;
}
void RosAlloc::ObjectsAllocatedCallback(void* start ATTRIBUTE_UNUSED, void* end ATTRIBUTE_UNUSED,
size_t used_bytes, void* arg) {
if (used_bytes == 0) {
return;
}
size_t* objects_allocated = reinterpret_cast<size_t*>(arg);
++(*objects_allocated);
}
void RosAlloc::Verify() {
Thread* self = Thread::Current();
CHECK(Locks::mutator_lock_->IsExclusiveHeld(self))
<< "The mutator locks isn't exclusively locked at " << __PRETTY_FUNCTION__;
MutexLock thread_list_mu(self, *Locks::thread_list_lock_);
ReaderMutexLock wmu(self, bulk_free_lock_);
std::vector<Run*> runs;
{
MutexLock lock_mu(self, lock_);
size_t pm_end = page_map_size_;
size_t i = 0;
size_t memory_tool_modifier = is_running_on_memory_tool_ ?
2 * ::art::gc::space::kDefaultMemoryToolRedZoneBytes : // Redzones before and after.
0;
while (i < pm_end) {
uint8_t pm = page_map_[i];
switch (pm) {
case kPageMapReleased:
// Fall-through.
case kPageMapEmpty: {
// The start of a free page run.
FreePageRun* fpr = reinterpret_cast<FreePageRun*>(base_ + i * kPageSize);
DCHECK_EQ(fpr->magic_num_, kMagicNumFree);
CHECK(free_page_runs_.find(fpr) != free_page_runs_.end())
<< "An empty page must belong to the free page run set";
size_t fpr_size = fpr->ByteSize(this);
CHECK(IsAligned<kPageSize>(fpr_size))
<< "A free page run size isn't page-aligned : " << fpr_size;
size_t num_pages = fpr_size / kPageSize;
CHECK_GT(num_pages, static_cast<uintptr_t>(0))
<< "A free page run size must be > 0 : " << fpr_size;
for (size_t j = i + 1; j < i + num_pages; ++j) {
CHECK(IsFreePage(j))
<< "A mismatch between the page map table for kPageMapEmpty "
<< " at page index " << j
<< " and the free page run size : page index range : "
<< i << " to " << (i + num_pages) << std::endl << DumpPageMap();
}
i += num_pages;
CHECK_LE(i, pm_end) << "Page map index " << i << " out of range < " << pm_end
<< std::endl << DumpPageMap();
break;
}
case kPageMapLargeObject: {
// The start of a large object.
size_t num_pages = 1;
size_t idx = i + 1;
while (idx < pm_end && page_map_[idx] == kPageMapLargeObjectPart) {
num_pages++;
idx++;
}
uint8_t* start = base_ + i * kPageSize;
if (is_running_on_memory_tool_) {
start += ::art::gc::space::kDefaultMemoryToolRedZoneBytes;
}
mirror::Object* obj = reinterpret_cast<mirror::Object*>(start);
size_t obj_size = obj->SizeOf();
CHECK_GT(obj_size + memory_tool_modifier, kLargeSizeThreshold)
<< "A rosalloc large object size must be > " << kLargeSizeThreshold;
CHECK_EQ(num_pages, RoundUp(obj_size + memory_tool_modifier, kPageSize) / kPageSize)
<< "A rosalloc large object size " << obj_size + memory_tool_modifier
<< " does not match the page map table " << (num_pages * kPageSize)
<< std::endl << DumpPageMap();
i += num_pages;
CHECK_LE(i, pm_end) << "Page map index " << i << " out of range < " << pm_end
<< std::endl << DumpPageMap();
break;
}
case kPageMapLargeObjectPart:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(pm) << std::endl << DumpPageMap();
break;
case kPageMapRun: {
// The start of a run.
Run* run = reinterpret_cast<Run*>(base_ + i * kPageSize);
DCHECK_EQ(run->magic_num_, kMagicNum);
size_t idx = run->size_bracket_idx_;
CHECK_LT(idx, kNumOfSizeBrackets) << "Out of range size bracket index : " << idx;
size_t num_pages = numOfPages[idx];
CHECK_GT(num_pages, static_cast<uintptr_t>(0))
<< "Run size must be > 0 : " << num_pages;
for (size_t j = i + 1; j < i + num_pages; ++j) {
CHECK_EQ(page_map_[j], kPageMapRunPart)
<< "A mismatch between the page map table for kPageMapRunPart "
<< " at page index " << j
<< " and the run size : page index range " << i << " to " << (i + num_pages)
<< std::endl << DumpPageMap();
}
// Don't verify the dedicated_full_run_ since it doesn't have any real allocations.
runs.push_back(run);
i += num_pages;
CHECK_LE(i, pm_end) << "Page map index " << i << " out of range < " << pm_end
<< std::endl << DumpPageMap();
break;
}
case kPageMapRunPart:
// Fall-through.
default:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(pm) << std::endl << DumpPageMap();
break;
}
}
}
std::list<Thread*> threads = Runtime::Current()->GetThreadList()->GetList();
for (Thread* thread : threads) {
for (size_t i = 0; i < kNumThreadLocalSizeBrackets; ++i) {
MutexLock brackets_mu(self, *size_bracket_locks_[i]);
Run* thread_local_run = reinterpret_cast<Run*>(thread->GetRosAllocRun(i));
CHECK(thread_local_run != nullptr);
CHECK(thread_local_run->IsThreadLocal());
CHECK(thread_local_run == dedicated_full_run_ ||
thread_local_run->size_bracket_idx_ == i);
}
}
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
MutexLock brackets_mu(self, *size_bracket_locks_[i]);
Run* current_run = current_runs_[i];
CHECK(current_run != nullptr);
if (current_run != dedicated_full_run_) {
// The dedicated full run is currently marked as thread local.
CHECK(!current_run->IsThreadLocal());
CHECK_EQ(current_run->size_bracket_idx_, i);
}
}
// Call Verify() here for the lock order.
for (auto& run : runs) {
run->Verify(self, this, is_running_on_memory_tool_);
}
}
void RosAlloc::Run::Verify(Thread* self, RosAlloc* rosalloc, bool running_on_memory_tool) {
DCHECK_EQ(magic_num_, kMagicNum) << "Bad magic number : " << Dump();
const size_t idx = size_bracket_idx_;
CHECK_LT(idx, kNumOfSizeBrackets) << "Out of range size bracket index : " << Dump();
uint8_t* slot_base = reinterpret_cast<uint8_t*>(this) + headerSizes[idx];
const size_t num_slots = numOfSlots[idx];
const size_t num_vec = RoundUp(num_slots, 32) / 32;
CHECK_GT(num_vec, 0U);
size_t bracket_size = IndexToBracketSize(idx);
CHECK_EQ(slot_base + num_slots * bracket_size,
reinterpret_cast<uint8_t*>(this) + numOfPages[idx] * kPageSize)
<< "Mismatch in the end address of the run " << Dump();
// Check that the bulk free bitmap is clean. It's only used during BulkFree().
CHECK(IsBulkFreeBitmapClean()) << "The bulk free bit map isn't clean " << Dump();
uint32_t last_word_mask = GetBitmapLastVectorMask(num_slots, num_vec);
// Make sure all the bits at the end of the run are set so that we don't allocate there.
CHECK_EQ(alloc_bit_map_[num_vec - 1] & last_word_mask, last_word_mask);
// Ensure that the first bitmap index is valid.
CHECK_LT(first_search_vec_idx_, num_vec);
// Check the thread local runs, the current runs, and the run sets.
if (IsThreadLocal()) {
// If it's a thread local run, then it must be pointed to by an owner thread.
bool owner_found = false;
std::list<Thread*> thread_list = Runtime::Current()->GetThreadList()->GetList();
for (auto it = thread_list.begin(); it != thread_list.end(); ++it) {
Thread* thread = *it;
for (size_t i = 0; i < kNumThreadLocalSizeBrackets; i++) {
MutexLock mu(self, *rosalloc->size_bracket_locks_[i]);
Run* thread_local_run = reinterpret_cast<Run*>(thread->GetRosAllocRun(i));
if (thread_local_run == this) {
CHECK(!owner_found)
<< "A thread local run has more than one owner thread " << Dump();
CHECK_EQ(i, idx)
<< "A mismatching size bracket index in a thread local run " << Dump();
owner_found = true;
}
}
}
CHECK(owner_found) << "A thread local run has no owner thread " << Dump();
} else {
// If it's not thread local, check that the thread local free bitmap is clean.
CHECK(IsThreadLocalFreeBitmapClean())
<< "A non-thread-local run's thread local free bitmap isn't clean "
<< Dump();
// Check if it's a current run for the size bucket.
bool is_current_run = false;
for (size_t i = 0; i < kNumOfSizeBrackets; i++) {
MutexLock mu(self, *rosalloc->size_bracket_locks_[i]);
Run* current_run = rosalloc->current_runs_[i];
if (idx == i) {
if (this == current_run) {
is_current_run = true;
}
} else {
// If the size bucket index does not match, then it must not
// be a current run.
CHECK_NE(this, current_run)
<< "A current run points to a run with a wrong size bracket index " << Dump();
}
}
// If it's neither a thread local or current run, then it must be
// in a run set.
if (!is_current_run) {
MutexLock mu(self, rosalloc->lock_);
auto& non_full_runs = rosalloc->non_full_runs_[idx];
// If it's all free, it must be a free page run rather than a run.
CHECK(!IsAllFree()) << "A free run must be in a free page run set " << Dump();
if (!IsFull()) {
// If it's not full, it must in the non-full run set.
CHECK(non_full_runs.find(this) != non_full_runs.end())
<< "A non-full run isn't in the non-full run set " << Dump();
} else {
// If it's full, it must in the full run set (debug build only.)
if (kIsDebugBuild) {
auto& full_runs = rosalloc->full_runs_[idx];
CHECK(full_runs.find(this) != full_runs.end())
<< " A full run isn't in the full run set " << Dump();
}
}
}
}
// Check each slot.
size_t slots = 0;
size_t memory_tool_modifier = running_on_memory_tool ?
2 * ::art::gc::space::kDefaultMemoryToolRedZoneBytes :
0U;
for (size_t v = 0; v < num_vec; v++, slots += 32) {
DCHECK_GE(num_slots, slots) << "Out of bounds";
uint32_t vec = alloc_bit_map_[v];
uint32_t thread_local_free_vec = ThreadLocalFreeBitMap()[v];
size_t end = std::min(num_slots - slots, static_cast<size_t>(32));
for (size_t i = 0; i < end; ++i) {
bool is_allocated = ((vec >> i) & 0x1) != 0;
// If a thread local run, slots may be marked freed in the
// thread local free bitmap.
bool is_thread_local_freed = IsThreadLocal() && ((thread_local_free_vec >> i) & 0x1) != 0;
if (is_allocated && !is_thread_local_freed) {
uint8_t* slot_addr = slot_base + (slots + i) * bracket_size;
if (running_on_memory_tool) {
slot_addr += ::art::gc::space::kDefaultMemoryToolRedZoneBytes;
}
mirror::Object* obj = reinterpret_cast<mirror::Object*>(slot_addr);
size_t obj_size = obj->SizeOf();
CHECK_LE(obj_size + memory_tool_modifier, kLargeSizeThreshold)
<< "A run slot contains a large object " << Dump();
CHECK_EQ(SizeToIndex(obj_size + memory_tool_modifier), idx)
<< PrettyTypeOf(obj) << " "
<< "obj_size=" << obj_size << "(" << obj_size + memory_tool_modifier << "), idx=" << idx
<< " A run slot contains an object with wrong size " << Dump();
}
}
}
}
size_t RosAlloc::ReleasePages() {
VLOG(heap) << "RosAlloc::ReleasePages()";
DCHECK(!DoesReleaseAllPages());
Thread* self = Thread::Current();
size_t reclaimed_bytes = 0;
size_t i = 0;
// Check the page map size which might have changed due to grow/shrink.
while (i < page_map_size_) {
// Reading the page map without a lock is racy but the race is benign since it should only
// result in occasionally not releasing pages which we could release.
uint8_t pm = page_map_[i];
switch (pm) {
case kPageMapReleased:
// Fall through.
case kPageMapEmpty: {
// This is currently the start of a free page run.
// Acquire the lock to prevent other threads racing in and modifying the page map.
MutexLock mu(self, lock_);
// Check that it's still empty after we acquired the lock since another thread could have
// raced in and placed an allocation here.
if (IsFreePage(i)) {
// Free page runs can start with a released page if we coalesced a released page free
// page run with an empty page run.
FreePageRun* fpr = reinterpret_cast<FreePageRun*>(base_ + i * kPageSize);
// There is a race condition where FreePage can coalesce fpr with the previous
// free page run before we acquire lock_. In that case free_page_runs_.find will not find
// a run starting at fpr. To handle this race, we skip reclaiming the page range and go
// to the next page.
if (free_page_runs_.find(fpr) != free_page_runs_.end()) {
size_t fpr_size = fpr->ByteSize(this);
DCHECK(IsAligned<kPageSize>(fpr_size));
uint8_t* start = reinterpret_cast<uint8_t*>(fpr);
reclaimed_bytes += ReleasePageRange(start, start + fpr_size);
size_t pages = fpr_size / kPageSize;
CHECK_GT(pages, 0U) << "Infinite loop probable";
i += pages;
DCHECK_LE(i, page_map_size_);
break;
}
}
FALLTHROUGH_INTENDED;
}
case kPageMapLargeObject: // Fall through.
case kPageMapLargeObjectPart: // Fall through.
case kPageMapRun: // Fall through.
case kPageMapRunPart: // Fall through.
++i;
break; // Skip.
default:
LOG(FATAL) << "Unreachable - page map type: " << static_cast<int>(pm);
break;
}
}
return reclaimed_bytes;
}
size_t RosAlloc::ReleasePageRange(uint8_t* start, uint8_t* end) {
DCHECK_ALIGNED(start, kPageSize);
DCHECK_ALIGNED(end, kPageSize);
DCHECK_LT(start, end);
if (kIsDebugBuild) {
// In the debug build, the first page of a free page run
// contains a magic number for debugging. Exclude it.
start += kPageSize;
// Single pages won't be released.
if (start == end) {
return 0;
}
}
if (!kMadviseZeroes) {
// TODO: Do this when we resurrect the page instead.
memset(start, 0, end - start);
}
CHECK_EQ(madvise(start, end - start, MADV_DONTNEED), 0);
size_t pm_idx = ToPageMapIndex(start);
size_t reclaimed_bytes = 0;
// Calculate reclaimed bytes and upate page map.
const size_t max_idx = pm_idx + (end - start) / kPageSize;
for (; pm_idx < max_idx; ++pm_idx) {
DCHECK(IsFreePage(pm_idx));
if (page_map_[pm_idx] == kPageMapEmpty) {
// Mark the page as released and update how many bytes we released.
reclaimed_bytes += kPageSize;
page_map_[pm_idx] = kPageMapReleased;
}
}
return reclaimed_bytes;
}
void RosAlloc::LogFragmentationAllocFailure(std::ostream& os, size_t failed_alloc_bytes) {
Thread* self = Thread::Current();
size_t largest_continuous_free_pages = 0;
WriterMutexLock wmu(self, bulk_free_lock_);
MutexLock mu(self, lock_);
for (FreePageRun* fpr : free_page_runs_) {
largest_continuous_free_pages = std::max(largest_continuous_free_pages,
fpr->ByteSize(this));
}
if (failed_alloc_bytes > kLargeSizeThreshold) {
// Large allocation.
size_t required_bytes = RoundUp(failed_alloc_bytes, kPageSize);
if (required_bytes > largest_continuous_free_pages) {
os << "; failed due to fragmentation (required continguous free "
<< required_bytes << " bytes where largest contiguous free "
<< largest_continuous_free_pages << " bytes)";
}
} else {
// Non-large allocation.
size_t required_bytes = numOfPages[SizeToIndex(failed_alloc_bytes)] * kPageSize;
if (required_bytes > largest_continuous_free_pages) {
os << "; failed due to fragmentation (required continguous free "
<< required_bytes << " bytes for a new buffer where largest contiguous free "
<< largest_continuous_free_pages << " bytes)";
}
}
}
} // namespace allocator
} // namespace gc
} // namespace art