/*
* Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
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*/
#include "precompiled.hpp"
#include "aot/aotLoader.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "gc/shared/collectorPolicy.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/allocation.hpp"
#include "memory/binaryTreeDictionary.inline.hpp"
#include "memory/filemap.hpp"
#include "memory/freeList.inline.hpp"
#include "memory/metachunk.hpp"
#include "memory/metaspace.hpp"
#include "memory/metaspace/metaspaceCommon.hpp"
#include "memory/metaspace/metaspaceStatistics.hpp"
#include "memory/metaspaceGCThresholdUpdater.hpp"
#include "memory/metaspaceShared.hpp"
#include "memory/metaspaceTracer.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "runtime/atomic.hpp"
#include "runtime/globals.hpp"
#include "runtime/init.hpp"
#include "runtime/java.hpp"
#include "runtime/mutex.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/orderAccess.inline.hpp"
#include "services/memTracker.hpp"
#include "services/memoryService.hpp"
#include "utilities/align.hpp"
#include "utilities/copy.hpp"
#include "utilities/debug.hpp"
#include "utilities/globalDefinitions.hpp"
#include "utilities/macros.hpp"
using namespace metaspace::internals;
typedef BinaryTreeDictionary<Metablock, FreeList<Metablock> > BlockTreeDictionary;
typedef BinaryTreeDictionary<Metachunk, FreeList<Metachunk> > ChunkTreeDictionary;
// Helper function that does a bunch of checks for a chunk.
DEBUG_ONLY(static void do_verify_chunk(Metachunk* chunk);)
// Given a Metachunk, update its in-use information (both in the
// chunk and the occupancy map).
static void do_update_in_use_info_for_chunk(Metachunk* chunk, bool inuse);
size_t const allocation_from_dictionary_limit = 4 * K;
MetaWord* last_allocated = 0;
size_t Metaspace::_compressed_class_space_size;
const MetaspaceTracer* Metaspace::_tracer = NULL;
DEBUG_ONLY(bool Metaspace::_frozen = false;)
// Internal statistics.
#ifdef ASSERT
static struct {
// Number of allocations.
uintx num_allocs;
// Number of times a ClassLoaderMetaspace was born...
uintx num_metaspace_births;
// ... and died.
uintx num_metaspace_deaths;
// Number of times VirtualSpaceListNodes were created...
uintx num_vsnodes_created;
// ... and purged.
uintx num_vsnodes_purged;
// Number of times we expanded the committed section of the space.
uintx num_committed_space_expanded;
// Number of deallocations
uintx num_deallocs;
// Number of deallocations triggered from outside ("real" deallocations).
uintx num_external_deallocs;
// Number of times an allocation was satisfied from deallocated blocks.
uintx num_allocs_from_deallocated_blocks;
} g_internal_statistics;
#endif
enum ChunkSizes { // in words.
ClassSpecializedChunk = 128,
SpecializedChunk = 128,
ClassSmallChunk = 256,
SmallChunk = 512,
ClassMediumChunk = 4 * K,
MediumChunk = 8 * K
};
// Returns size of this chunk type.
size_t get_size_for_nonhumongous_chunktype(ChunkIndex chunktype, bool is_class) {
assert(is_valid_nonhumongous_chunktype(chunktype), "invalid chunk type.");
size_t size = 0;
if (is_class) {
switch(chunktype) {
case SpecializedIndex: size = ClassSpecializedChunk; break;
case SmallIndex: size = ClassSmallChunk; break;
case MediumIndex: size = ClassMediumChunk; break;
default:
ShouldNotReachHere();
}
} else {
switch(chunktype) {
case SpecializedIndex: size = SpecializedChunk; break;
case SmallIndex: size = SmallChunk; break;
case MediumIndex: size = MediumChunk; break;
default:
ShouldNotReachHere();
}
}
return size;
}
ChunkIndex get_chunk_type_by_size(size_t size, bool is_class) {
if (is_class) {
if (size == ClassSpecializedChunk) {
return SpecializedIndex;
} else if (size == ClassSmallChunk) {
return SmallIndex;
} else if (size == ClassMediumChunk) {
return MediumIndex;
} else if (size > ClassMediumChunk) {
// A valid humongous chunk size is a multiple of the smallest chunk size.
assert(is_aligned(size, ClassSpecializedChunk), "Invalid chunk size");
return HumongousIndex;
}
} else {
if (size == SpecializedChunk) {
return SpecializedIndex;
} else if (size == SmallChunk) {
return SmallIndex;
} else if (size == MediumChunk) {
return MediumIndex;
} else if (size > MediumChunk) {
// A valid humongous chunk size is a multiple of the smallest chunk size.
assert(is_aligned(size, SpecializedChunk), "Invalid chunk size");
return HumongousIndex;
}
}
ShouldNotReachHere();
return (ChunkIndex)-1;
}
ChunkIndex next_chunk_index(ChunkIndex i) {
assert(i < NumberOfInUseLists, "Out of bound");
return (ChunkIndex) (i+1);
}
ChunkIndex prev_chunk_index(ChunkIndex i) {
assert(i > ZeroIndex, "Out of bound");
return (ChunkIndex) (i-1);
}
static const char* space_type_name(Metaspace::MetaspaceType t) {
const char* s = NULL;
switch (t) {
case Metaspace::StandardMetaspaceType: s = "Standard"; break;
case Metaspace::BootMetaspaceType: s = "Boot"; break;
case Metaspace::AnonymousMetaspaceType: s = "Anonymous"; break;
case Metaspace::ReflectionMetaspaceType: s = "Reflection"; break;
default: ShouldNotReachHere();
}
return s;
}
volatile intptr_t MetaspaceGC::_capacity_until_GC = 0;
uint MetaspaceGC::_shrink_factor = 0;
bool MetaspaceGC::_should_concurrent_collect = false;
typedef class FreeList<Metachunk> ChunkList;
// Manages the global free lists of chunks.
class ChunkManager : public CHeapObj<mtInternal> {
friend class TestVirtualSpaceNodeTest;
// Free list of chunks of different sizes.
// SpecializedChunk
// SmallChunk
// MediumChunk
ChunkList _free_chunks[NumberOfFreeLists];
// Whether or not this is the class chunkmanager.
const bool _is_class;
// Return non-humongous chunk list by its index.
ChunkList* free_chunks(ChunkIndex index);
// Returns non-humongous chunk list for the given chunk word size.
ChunkList* find_free_chunks_list(size_t word_size);
// HumongousChunk
ChunkTreeDictionary _humongous_dictionary;
// Returns the humongous chunk dictionary.
ChunkTreeDictionary* humongous_dictionary() {
return &_humongous_dictionary;
}
// Size, in metaspace words, of all chunks managed by this ChunkManager
size_t _free_chunks_total;
// Number of chunks in this ChunkManager
size_t _free_chunks_count;
// Update counters after a chunk was added or removed removed.
void account_for_added_chunk(const Metachunk* c);
void account_for_removed_chunk(const Metachunk* c);
// Debug support
size_t sum_free_chunks();
size_t sum_free_chunks_count();
void locked_verify_free_chunks_total();
void slow_locked_verify_free_chunks_total() {
if (VerifyMetaspace) {
locked_verify_free_chunks_total();
}
}
void locked_verify_free_chunks_count();
void slow_locked_verify_free_chunks_count() {
if (VerifyMetaspace) {
locked_verify_free_chunks_count();
}
}
// Given a pointer to a chunk, attempts to merge it with neighboring
// free chunks to form a bigger chunk. Returns true if successful.
bool attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type);
// Helper for chunk merging:
// Given an address range with 1-n chunks which are all supposed to be
// free and hence currently managed by this ChunkManager, remove them
// from this ChunkManager and mark them as invalid.
// - This does not correct the occupancy map.
// - This does not adjust the counters in ChunkManager.
// - Does not adjust container count counter in containing VirtualSpaceNode.
// Returns number of chunks removed.
int remove_chunks_in_area(MetaWord* p, size_t word_size);
// Helper for chunk splitting: given a target chunk size and a larger free chunk,
// split up the larger chunk into n smaller chunks, at least one of which should be
// the target chunk of target chunk size. The smaller chunks, including the target
// chunk, are returned to the freelist. The pointer to the target chunk is returned.
// Note that this chunk is supposed to be removed from the freelist right away.
Metachunk* split_chunk(size_t target_chunk_word_size, Metachunk* chunk);
public:
ChunkManager(bool is_class)
: _is_class(is_class), _free_chunks_total(0), _free_chunks_count(0) {
_free_chunks[SpecializedIndex].set_size(get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class));
_free_chunks[SmallIndex].set_size(get_size_for_nonhumongous_chunktype(SmallIndex, is_class));
_free_chunks[MediumIndex].set_size(get_size_for_nonhumongous_chunktype(MediumIndex, is_class));
}
// Add or delete (return) a chunk to the global freelist.
Metachunk* chunk_freelist_allocate(size_t word_size);
// Map a size to a list index assuming that there are lists
// for special, small, medium, and humongous chunks.
ChunkIndex list_index(size_t size);
// Map a given index to the chunk size.
size_t size_by_index(ChunkIndex index) const;
bool is_class() const { return _is_class; }
// Convenience accessors.
size_t medium_chunk_word_size() const { return size_by_index(MediumIndex); }
size_t small_chunk_word_size() const { return size_by_index(SmallIndex); }
size_t specialized_chunk_word_size() const { return size_by_index(SpecializedIndex); }
// Take a chunk from the ChunkManager. The chunk is expected to be in
// the chunk manager (the freelist if non-humongous, the dictionary if
// humongous).
void remove_chunk(Metachunk* chunk);
// Return a single chunk of type index to the ChunkManager.
void return_single_chunk(Metachunk* chunk);
// Add the simple linked list of chunks to the freelist of chunks
// of type index.
void return_chunk_list(Metachunk* chunks);
// Total of the space in the free chunks list
size_t free_chunks_total_words();
size_t free_chunks_total_bytes();
// Number of chunks in the free chunks list
size_t free_chunks_count();
// Remove from a list by size. Selects list based on size of chunk.
Metachunk* free_chunks_get(size_t chunk_word_size);
#define index_bounds_check(index) \
assert(is_valid_chunktype(index), "Bad index: %d", (int) index)
size_t num_free_chunks(ChunkIndex index) const {
index_bounds_check(index);
if (index == HumongousIndex) {
return _humongous_dictionary.total_free_blocks();
}
ssize_t count = _free_chunks[index].count();
return count == -1 ? 0 : (size_t) count;
}
size_t size_free_chunks_in_bytes(ChunkIndex index) const {
index_bounds_check(index);
size_t word_size = 0;
if (index == HumongousIndex) {
word_size = _humongous_dictionary.total_size();
} else {
const size_t size_per_chunk_in_words = _free_chunks[index].size();
word_size = size_per_chunk_in_words * num_free_chunks(index);
}
return word_size * BytesPerWord;
}
MetaspaceChunkFreeListSummary chunk_free_list_summary() const {
return MetaspaceChunkFreeListSummary(num_free_chunks(SpecializedIndex),
num_free_chunks(SmallIndex),
num_free_chunks(MediumIndex),
num_free_chunks(HumongousIndex),
size_free_chunks_in_bytes(SpecializedIndex),
size_free_chunks_in_bytes(SmallIndex),
size_free_chunks_in_bytes(MediumIndex),
size_free_chunks_in_bytes(HumongousIndex));
}
// Debug support
void verify();
void slow_verify() {
if (VerifyMetaspace) {
verify();
}
}
void locked_verify();
void slow_locked_verify() {
if (VerifyMetaspace) {
locked_verify();
}
}
void locked_print_free_chunks(outputStream* st);
void locked_print_sum_free_chunks(outputStream* st);
// Fill in current statistic values to the given statistics object.
void collect_statistics(ChunkManagerStatistics* out) const;
};
class SmallBlocks : public CHeapObj<mtClass> {
const static uint _small_block_max_size = sizeof(TreeChunk<Metablock, FreeList<Metablock> >)/HeapWordSize;
// Note: this corresponds to the imposed miminum allocation size, see SpaceManager::get_allocation_word_size()
const static uint _small_block_min_size = sizeof(Metablock)/HeapWordSize;
private:
FreeList<Metablock> _small_lists[_small_block_max_size - _small_block_min_size];
FreeList<Metablock>& list_at(size_t word_size) {
assert(word_size >= _small_block_min_size, "There are no metaspace objects less than %u words", _small_block_min_size);
return _small_lists[word_size - _small_block_min_size];
}
public:
SmallBlocks() {
for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
uint k = i - _small_block_min_size;
_small_lists[k].set_size(i);
}
}
// Returns the total size, in words, of all blocks, across all block sizes.
size_t total_size() const {
size_t result = 0;
for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
uint k = i - _small_block_min_size;
result = result + _small_lists[k].count() * _small_lists[k].size();
}
return result;
}
// Returns the total number of all blocks across all block sizes.
uintx total_num_blocks() const {
uintx result = 0;
for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
uint k = i - _small_block_min_size;
result = result + _small_lists[k].count();
}
return result;
}
static uint small_block_max_size() { return _small_block_max_size; }
static uint small_block_min_size() { return _small_block_min_size; }
MetaWord* get_block(size_t word_size) {
if (list_at(word_size).count() > 0) {
MetaWord* new_block = (MetaWord*) list_at(word_size).get_chunk_at_head();
return new_block;
} else {
return NULL;
}
}
void return_block(Metablock* free_chunk, size_t word_size) {
list_at(word_size).return_chunk_at_head(free_chunk, false);
assert(list_at(word_size).count() > 0, "Should have a chunk");
}
void print_on(outputStream* st) const {
st->print_cr("SmallBlocks:");
for (uint i = _small_block_min_size; i < _small_block_max_size; i++) {
uint k = i - _small_block_min_size;
st->print_cr("small_lists size " SIZE_FORMAT " count " SIZE_FORMAT, _small_lists[k].size(), _small_lists[k].count());
}
}
};
// Used to manage the free list of Metablocks (a block corresponds
// to the allocation of a quantum of metadata).
class BlockFreelist : public CHeapObj<mtClass> {
BlockTreeDictionary* const _dictionary;
SmallBlocks* _small_blocks;
// Only allocate and split from freelist if the size of the allocation
// is at least 1/4th the size of the available block.
const static int WasteMultiplier = 4;
// Accessors
BlockTreeDictionary* dictionary() const { return _dictionary; }
SmallBlocks* small_blocks() {
if (_small_blocks == NULL) {
_small_blocks = new SmallBlocks();
}
return _small_blocks;
}
public:
BlockFreelist();
~BlockFreelist();
// Get and return a block to the free list
MetaWord* get_block(size_t word_size);
void return_block(MetaWord* p, size_t word_size);
// Returns the total size, in words, of all blocks kept in this structure.
size_t total_size() const {
size_t result = dictionary()->total_size();
if (_small_blocks != NULL) {
result = result + _small_blocks->total_size();
}
return result;
}
// Returns the number of all blocks kept in this structure.
uintx num_blocks() const {
uintx result = dictionary()->total_free_blocks();
if (_small_blocks != NULL) {
result = result + _small_blocks->total_num_blocks();
}
return result;
}
static size_t min_dictionary_size() { return TreeChunk<Metablock, FreeList<Metablock> >::min_size(); }
void print_on(outputStream* st) const;
};
// Helper for Occupancy Bitmap. A type trait to give an all-bits-are-one-unsigned constant.
template <typename T> struct all_ones { static const T value; };
template <> struct all_ones <uint64_t> { static const uint64_t value = 0xFFFFFFFFFFFFFFFFULL; };
template <> struct all_ones <uint32_t> { static const uint32_t value = 0xFFFFFFFF; };
// The OccupancyMap is a bitmap which, for a given VirtualSpaceNode,
// keeps information about
// - where a chunk starts
// - whether a chunk is in-use or free
// A bit in this bitmap represents one range of memory in the smallest
// chunk size (SpecializedChunk or ClassSpecializedChunk).
class OccupancyMap : public CHeapObj<mtInternal> {
// The address range this map covers.
const MetaWord* const _reference_address;
const size_t _word_size;
// The word size of a specialized chunk, aka the number of words one
// bit in this map represents.
const size_t _smallest_chunk_word_size;
// map data
// Data are organized in two bit layers:
// The first layer is the chunk-start-map. Here, a bit is set to mark
// the corresponding region as the head of a chunk.
// The second layer is the in-use-map. Here, a set bit indicates that
// the corresponding belongs to a chunk which is in use.
uint8_t* _map[2];
enum { layer_chunk_start_map = 0, layer_in_use_map = 1 };
// length, in bytes, of bitmap data
size_t _map_size;
// Returns true if bit at position pos at bit-layer layer is set.
bool get_bit_at_position(unsigned pos, unsigned layer) const {
assert(layer == 0 || layer == 1, "Invalid layer %d", layer);
const unsigned byteoffset = pos / 8;
assert(byteoffset < _map_size,
"invalid byte offset (%u), map size is " SIZE_FORMAT ".", byteoffset, _map_size);
const unsigned mask = 1 << (pos % 8);
return (_map[layer][byteoffset] & mask) > 0;
}
// Changes bit at position pos at bit-layer layer to value v.
void set_bit_at_position(unsigned pos, unsigned layer, bool v) {
assert(layer == 0 || layer == 1, "Invalid layer %d", layer);
const unsigned byteoffset = pos / 8;
assert(byteoffset < _map_size,
"invalid byte offset (%u), map size is " SIZE_FORMAT ".", byteoffset, _map_size);
const unsigned mask = 1 << (pos % 8);
if (v) {
_map[layer][byteoffset] |= mask;
} else {
_map[layer][byteoffset] &= ~mask;
}
}
// Optimized case of is_any_bit_set_in_region for 32/64bit aligned access:
// pos is 32/64 aligned and num_bits is 32/64.
// This is the typical case when coalescing to medium chunks, whose size is
// 32 or 64 times the specialized chunk size (depending on class or non class
// case), so they occupy 64 bits which should be 64bit aligned, because
// chunks are chunk-size aligned.
template <typename T>
bool is_any_bit_set_in_region_3264(unsigned pos, unsigned num_bits, unsigned layer) const {
assert(_map_size > 0, "not initialized");
assert(layer == 0 || layer == 1, "Invalid layer %d.", layer);
assert(pos % (sizeof(T) * 8) == 0, "Bit position must be aligned (%u).", pos);
assert(num_bits == (sizeof(T) * 8), "Number of bits incorrect (%u).", num_bits);
const size_t byteoffset = pos / 8;
assert(byteoffset <= (_map_size - sizeof(T)),
"Invalid byte offset (" SIZE_FORMAT "), map size is " SIZE_FORMAT ".", byteoffset, _map_size);
const T w = *(T*)(_map[layer] + byteoffset);
return w > 0 ? true : false;
}
// Returns true if any bit in region [pos1, pos1 + num_bits) is set in bit-layer layer.
bool is_any_bit_set_in_region(unsigned pos, unsigned num_bits, unsigned layer) const {
if (pos % 32 == 0 && num_bits == 32) {
return is_any_bit_set_in_region_3264<uint32_t>(pos, num_bits, layer);
} else if (pos % 64 == 0 && num_bits == 64) {
return is_any_bit_set_in_region_3264<uint64_t>(pos, num_bits, layer);
} else {
for (unsigned n = 0; n < num_bits; n ++) {
if (get_bit_at_position(pos + n, layer)) {
return true;
}
}
}
return false;
}
// Returns true if any bit in region [p, p+word_size) is set in bit-layer layer.
bool is_any_bit_set_in_region(MetaWord* p, size_t word_size, unsigned layer) const {
assert(word_size % _smallest_chunk_word_size == 0,
"Region size " SIZE_FORMAT " not a multiple of smallest chunk size.", word_size);
const unsigned pos = get_bitpos_for_address(p);
const unsigned num_bits = (unsigned) (word_size / _smallest_chunk_word_size);
return is_any_bit_set_in_region(pos, num_bits, layer);
}
// Optimized case of set_bits_of_region for 32/64bit aligned access:
// pos is 32/64 aligned and num_bits is 32/64.
// This is the typical case when coalescing to medium chunks, whose size
// is 32 or 64 times the specialized chunk size (depending on class or non
// class case), so they occupy 64 bits which should be 64bit aligned,
// because chunks are chunk-size aligned.
template <typename T>
void set_bits_of_region_T(unsigned pos, unsigned num_bits, unsigned layer, bool v) {
assert(pos % (sizeof(T) * 8) == 0, "Bit position must be aligned to %u (%u).",
(unsigned)(sizeof(T) * 8), pos);
assert(num_bits == (sizeof(T) * 8), "Number of bits incorrect (%u), expected %u.",
num_bits, (unsigned)(sizeof(T) * 8));
const size_t byteoffset = pos / 8;
assert(byteoffset <= (_map_size - sizeof(T)),
"invalid byte offset (" SIZE_FORMAT "), map size is " SIZE_FORMAT ".", byteoffset, _map_size);
T* const pw = (T*)(_map[layer] + byteoffset);
*pw = v ? all_ones<T>::value : (T) 0;
}
// Set all bits in a region starting at pos to a value.
void set_bits_of_region(unsigned pos, unsigned num_bits, unsigned layer, bool v) {
assert(_map_size > 0, "not initialized");
assert(layer == 0 || layer == 1, "Invalid layer %d.", layer);
if (pos % 32 == 0 && num_bits == 32) {
set_bits_of_region_T<uint32_t>(pos, num_bits, layer, v);
} else if (pos % 64 == 0 && num_bits == 64) {
set_bits_of_region_T<uint64_t>(pos, num_bits, layer, v);
} else {
for (unsigned n = 0; n < num_bits; n ++) {
set_bit_at_position(pos + n, layer, v);
}
}
}
// Helper: sets all bits in a region [p, p+word_size).
void set_bits_of_region(MetaWord* p, size_t word_size, unsigned layer, bool v) {
assert(word_size % _smallest_chunk_word_size == 0,
"Region size " SIZE_FORMAT " not a multiple of smallest chunk size.", word_size);
const unsigned pos = get_bitpos_for_address(p);
const unsigned num_bits = (unsigned) (word_size / _smallest_chunk_word_size);
set_bits_of_region(pos, num_bits, layer, v);
}
// Helper: given an address, return the bit position representing that address.
unsigned get_bitpos_for_address(const MetaWord* p) const {
assert(_reference_address != NULL, "not initialized");
assert(p >= _reference_address && p < _reference_address + _word_size,
"Address %p out of range for occupancy map [%p..%p).",
p, _reference_address, _reference_address + _word_size);
assert(is_aligned(p, _smallest_chunk_word_size * sizeof(MetaWord)),
"Address not aligned (%p).", p);
const ptrdiff_t d = (p - _reference_address) / _smallest_chunk_word_size;
assert(d >= 0 && (size_t)d < _map_size * 8, "Sanity.");
return (unsigned) d;
}
public:
OccupancyMap(const MetaWord* reference_address, size_t word_size, size_t smallest_chunk_word_size) :
_reference_address(reference_address), _word_size(word_size),
_smallest_chunk_word_size(smallest_chunk_word_size) {
assert(reference_address != NULL, "invalid reference address");
assert(is_aligned(reference_address, smallest_chunk_word_size),
"Reference address not aligned to smallest chunk size.");
assert(is_aligned(word_size, smallest_chunk_word_size),
"Word_size shall be a multiple of the smallest chunk size.");
// Calculate bitmap size: one bit per smallest_chunk_word_size'd area.
size_t num_bits = word_size / smallest_chunk_word_size;
_map_size = (num_bits + 7) / 8;
assert(_map_size * 8 >= num_bits, "sanity");
_map[0] = (uint8_t*) os::malloc(_map_size, mtInternal);
_map[1] = (uint8_t*) os::malloc(_map_size, mtInternal);
assert(_map[0] != NULL && _map[1] != NULL, "Occupancy Map: allocation failed.");
memset(_map[1], 0, _map_size);
memset(_map[0], 0, _map_size);
// Sanity test: the first respectively last possible chunk start address in
// the covered range shall map to the first and last bit in the bitmap.
assert(get_bitpos_for_address(reference_address) == 0,
"First chunk address in range must map to fist bit in bitmap.");
assert(get_bitpos_for_address(reference_address + word_size - smallest_chunk_word_size) == num_bits - 1,
"Last chunk address in range must map to last bit in bitmap.");
}
~OccupancyMap() {
os::free(_map[0]);
os::free(_map[1]);
}
// Returns true if at address x a chunk is starting.
bool chunk_starts_at_address(MetaWord* p) const {
const unsigned pos = get_bitpos_for_address(p);
return get_bit_at_position(pos, layer_chunk_start_map);
}
void set_chunk_starts_at_address(MetaWord* p, bool v) {
const unsigned pos = get_bitpos_for_address(p);
set_bit_at_position(pos, layer_chunk_start_map, v);
}
// Removes all chunk-start-bits inside a region, typically as a
// result of a chunk merge.
void wipe_chunk_start_bits_in_region(MetaWord* p, size_t word_size) {
set_bits_of_region(p, word_size, layer_chunk_start_map, false);
}
// Returns true if there are life (in use) chunks in the region limited
// by [p, p+word_size).
bool is_region_in_use(MetaWord* p, size_t word_size) const {
return is_any_bit_set_in_region(p, word_size, layer_in_use_map);
}
// Marks the region starting at p with the size word_size as in use
// or free, depending on v.
void set_region_in_use(MetaWord* p, size_t word_size, bool v) {
set_bits_of_region(p, word_size, layer_in_use_map, v);
}
#ifdef ASSERT
// Verify occupancy map for the address range [from, to).
// We need to tell it the address range, because the memory the
// occupancy map is covering may not be fully comitted yet.
void verify(MetaWord* from, MetaWord* to) {
Metachunk* chunk = NULL;
int nth_bit_for_chunk = 0;
MetaWord* chunk_end = NULL;
for (MetaWord* p = from; p < to; p += _smallest_chunk_word_size) {
const unsigned pos = get_bitpos_for_address(p);
// Check the chunk-starts-info:
if (get_bit_at_position(pos, layer_chunk_start_map)) {
// Chunk start marked in bitmap.
chunk = (Metachunk*) p;
if (chunk_end != NULL) {
assert(chunk_end == p, "Unexpected chunk start found at %p (expected "
"the next chunk to start at %p).", p, chunk_end);
}
assert(chunk->is_valid_sentinel(), "Invalid chunk at address %p.", p);
if (chunk->get_chunk_type() != HumongousIndex) {
guarantee(is_aligned(p, chunk->word_size()), "Chunk %p not aligned.", p);
}
chunk_end = p + chunk->word_size();
nth_bit_for_chunk = 0;
assert(chunk_end <= to, "Chunk end overlaps test address range.");
} else {
// No chunk start marked in bitmap.
assert(chunk != NULL, "Chunk should start at start of address range.");
assert(p < chunk_end, "Did not find expected chunk start at %p.", p);
nth_bit_for_chunk ++;
}
// Check the in-use-info:
const bool in_use_bit = get_bit_at_position(pos, layer_in_use_map);
if (in_use_bit) {
assert(!chunk->is_tagged_free(), "Chunk %p: marked in-use in map but is free (bit %u).",
chunk, nth_bit_for_chunk);
} else {
assert(chunk->is_tagged_free(), "Chunk %p: marked free in map but is in use (bit %u).",
chunk, nth_bit_for_chunk);
}
}
}
// Verify that a given chunk is correctly accounted for in the bitmap.
void verify_for_chunk(Metachunk* chunk) {
assert(chunk_starts_at_address((MetaWord*) chunk),
"No chunk start marked in map for chunk %p.", chunk);
// For chunks larger than the minimal chunk size, no other chunk
// must start in its area.
if (chunk->word_size() > _smallest_chunk_word_size) {
assert(!is_any_bit_set_in_region(((MetaWord*) chunk) + _smallest_chunk_word_size,
chunk->word_size() - _smallest_chunk_word_size, layer_chunk_start_map),
"No chunk must start within another chunk.");
}
if (!chunk->is_tagged_free()) {
assert(is_region_in_use((MetaWord*)chunk, chunk->word_size()),
"Chunk %p is in use but marked as free in map (%d %d).",
chunk, chunk->get_chunk_type(), chunk->get_origin());
} else {
assert(!is_region_in_use((MetaWord*)chunk, chunk->word_size()),
"Chunk %p is free but marked as in-use in map (%d %d).",
chunk, chunk->get_chunk_type(), chunk->get_origin());
}
}
#endif // ASSERT
};
// A VirtualSpaceList node.
class VirtualSpaceNode : public CHeapObj<mtClass> {
friend class VirtualSpaceList;
// Link to next VirtualSpaceNode
VirtualSpaceNode* _next;
// Whether this node is contained in class or metaspace.
const bool _is_class;
// total in the VirtualSpace
MemRegion _reserved;
ReservedSpace _rs;
VirtualSpace _virtual_space;
MetaWord* _top;
// count of chunks contained in this VirtualSpace
uintx _container_count;
OccupancyMap* _occupancy_map;
// Convenience functions to access the _virtual_space
char* low() const { return virtual_space()->low(); }
char* high() const { return virtual_space()->high(); }
// The first Metachunk will be allocated at the bottom of the
// VirtualSpace
Metachunk* first_chunk() { return (Metachunk*) bottom(); }
// Committed but unused space in the virtual space
size_t free_words_in_vs() const;
// True if this node belongs to class metaspace.
bool is_class() const { return _is_class; }
// Helper function for take_from_committed: allocate padding chunks
// until top is at the given address.
void allocate_padding_chunks_until_top_is_at(MetaWord* target_top);
public:
VirtualSpaceNode(bool is_class, size_t byte_size);
VirtualSpaceNode(bool is_class, ReservedSpace rs) :
_is_class(is_class), _top(NULL), _next(NULL), _rs(rs), _container_count(0), _occupancy_map(NULL) {}
~VirtualSpaceNode();
// Convenience functions for logical bottom and end
MetaWord* bottom() const { return (MetaWord*) _virtual_space.low(); }
MetaWord* end() const { return (MetaWord*) _virtual_space.high(); }
const OccupancyMap* occupancy_map() const { return _occupancy_map; }
OccupancyMap* occupancy_map() { return _occupancy_map; }
bool contains(const void* ptr) { return ptr >= low() && ptr < high(); }
size_t reserved_words() const { return _virtual_space.reserved_size() / BytesPerWord; }
size_t committed_words() const { return _virtual_space.actual_committed_size() / BytesPerWord; }
bool is_pre_committed() const { return _virtual_space.special(); }
// address of next available space in _virtual_space;
// Accessors
VirtualSpaceNode* next() { return _next; }
void set_next(VirtualSpaceNode* v) { _next = v; }
void set_reserved(MemRegion const v) { _reserved = v; }
void set_top(MetaWord* v) { _top = v; }
// Accessors
MemRegion* reserved() { return &_reserved; }
VirtualSpace* virtual_space() const { return (VirtualSpace*) &_virtual_space; }
// Returns true if "word_size" is available in the VirtualSpace
bool is_available(size_t word_size) { return word_size <= pointer_delta(end(), _top, sizeof(MetaWord)); }
MetaWord* top() const { return _top; }
void inc_top(size_t word_size) { _top += word_size; }
uintx container_count() { return _container_count; }
void inc_container_count();
void dec_container_count();
#ifdef ASSERT
uintx container_count_slow();
void verify_container_count();
#endif
// used and capacity in this single entry in the list
size_t used_words_in_vs() const;
size_t capacity_words_in_vs() const;
bool initialize();
// get space from the virtual space
Metachunk* take_from_committed(size_t chunk_word_size);
// Allocate a chunk from the virtual space and return it.
Metachunk* get_chunk_vs(size_t chunk_word_size);
// Expands/shrinks the committed space in a virtual space. Delegates
// to Virtualspace
bool expand_by(size_t min_words, size_t preferred_words);
// In preparation for deleting this node, remove all the chunks
// in the node from any freelist.
void purge(ChunkManager* chunk_manager);
// If an allocation doesn't fit in the current node a new node is created.
// Allocate chunks out of the remaining committed space in this node
// to avoid wasting that memory.
// This always adds up because all the chunk sizes are multiples of
// the smallest chunk size.
void retire(ChunkManager* chunk_manager);
void print_on(outputStream* st) const { print_on(st, K); }
void print_on(outputStream* st, size_t scale) const;
void print_map(outputStream* st, bool is_class) const;
// Debug support
DEBUG_ONLY(void mangle();)
// Verify counters, all chunks in this list node and the occupancy map.
DEBUG_ONLY(void verify();)
// Verify that all free chunks in this node are ideally merged
// (there not should be multiple small chunks where a large chunk could exist.)
DEBUG_ONLY(void verify_free_chunks_are_ideally_merged();)
};
#define assert_is_aligned(value, alignment) \
assert(is_aligned((value), (alignment)), \
SIZE_FORMAT_HEX " is not aligned to " \
SIZE_FORMAT, (size_t)(uintptr_t)value, (alignment))
#define assert_counter(expected_value, real_value, msg) \
assert( (expected_value) == (real_value), \
"Counter mismatch (%s): expected " SIZE_FORMAT \
", but got: " SIZE_FORMAT ".", msg, expected_value, \
real_value);
// Decide if large pages should be committed when the memory is reserved.
static bool should_commit_large_pages_when_reserving(size_t bytes) {
if (UseLargePages && UseLargePagesInMetaspace && !os::can_commit_large_page_memory()) {
size_t words = bytes / BytesPerWord;
bool is_class = false; // We never reserve large pages for the class space.
if (MetaspaceGC::can_expand(words, is_class) &&
MetaspaceGC::allowed_expansion() >= words) {
return true;
}
}
return false;
}
// byte_size is the size of the associated virtualspace.
VirtualSpaceNode::VirtualSpaceNode(bool is_class, size_t bytes) :
_is_class(is_class), _top(NULL), _next(NULL), _rs(), _container_count(0), _occupancy_map(NULL) {
assert_is_aligned(bytes, Metaspace::reserve_alignment());
bool large_pages = should_commit_large_pages_when_reserving(bytes);
_rs = ReservedSpace(bytes, Metaspace::reserve_alignment(), large_pages);
if (_rs.is_reserved()) {
assert(_rs.base() != NULL, "Catch if we get a NULL address");
assert(_rs.size() != 0, "Catch if we get a 0 size");
assert_is_aligned(_rs.base(), Metaspace::reserve_alignment());
assert_is_aligned(_rs.size(), Metaspace::reserve_alignment());
MemTracker::record_virtual_memory_type((address)_rs.base(), mtClass);
}
}
void VirtualSpaceNode::purge(ChunkManager* chunk_manager) {
DEBUG_ONLY(this->verify();)
Metachunk* chunk = first_chunk();
Metachunk* invalid_chunk = (Metachunk*) top();
while (chunk < invalid_chunk ) {
assert(chunk->is_tagged_free(), "Should be tagged free");
MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();
chunk_manager->remove_chunk(chunk);
chunk->remove_sentinel();
assert(chunk->next() == NULL &&
chunk->prev() == NULL,
"Was not removed from its list");
chunk = (Metachunk*) next;
}
}
void VirtualSpaceNode::print_map(outputStream* st, bool is_class) const {
if (bottom() == top()) {
return;
}
const size_t spec_chunk_size = is_class ? ClassSpecializedChunk : SpecializedChunk;
const size_t small_chunk_size = is_class ? ClassSmallChunk : SmallChunk;
const size_t med_chunk_size = is_class ? ClassMediumChunk : MediumChunk;
int line_len = 100;
const size_t section_len = align_up(spec_chunk_size * line_len, med_chunk_size);
line_len = (int)(section_len / spec_chunk_size);
static const int NUM_LINES = 4;
char* lines[NUM_LINES];
for (int i = 0; i < NUM_LINES; i ++) {
lines[i] = (char*)os::malloc(line_len, mtInternal);
}
int pos = 0;
const MetaWord* p = bottom();
const Metachunk* chunk = (const Metachunk*)p;
const MetaWord* chunk_end = p + chunk->word_size();
while (p < top()) {
if (pos == line_len) {
pos = 0;
for (int i = 0; i < NUM_LINES; i ++) {
st->fill_to(22);
st->print_raw(lines[i], line_len);
st->cr();
}
}
if (pos == 0) {
st->print(PTR_FORMAT ":", p2i(p));
}
if (p == chunk_end) {
chunk = (Metachunk*)p;
chunk_end = p + chunk->word_size();
}
// line 1: chunk starting points (a dot if that area is a chunk start).
lines[0][pos] = p == (const MetaWord*)chunk ? '.' : ' ';
// Line 2: chunk type (x=spec, s=small, m=medium, h=humongous), uppercase if
// chunk is in use.
const bool chunk_is_free = ((Metachunk*)chunk)->is_tagged_free();
if (chunk->word_size() == spec_chunk_size) {
lines[1][pos] = chunk_is_free ? 'x' : 'X';
} else if (chunk->word_size() == small_chunk_size) {
lines[1][pos] = chunk_is_free ? 's' : 'S';
} else if (chunk->word_size() == med_chunk_size) {
lines[1][pos] = chunk_is_free ? 'm' : 'M';
} else if (chunk->word_size() > med_chunk_size) {
lines[1][pos] = chunk_is_free ? 'h' : 'H';
} else {
ShouldNotReachHere();
}
// Line 3: chunk origin
const ChunkOrigin origin = chunk->get_origin();
lines[2][pos] = origin == origin_normal ? ' ' : '0' + (int) origin;
// Line 4: Virgin chunk? Virgin chunks are chunks created as a byproduct of padding or splitting,
// but were never used.
lines[3][pos] = chunk->get_use_count() > 0 ? ' ' : 'v';
p += spec_chunk_size;
pos ++;
}
if (pos > 0) {
for (int i = 0; i < NUM_LINES; i ++) {
st->fill_to(22);
st->print_raw(lines[i], line_len);
st->cr();
}
}
for (int i = 0; i < NUM_LINES; i ++) {
os::free(lines[i]);
}
}
#ifdef ASSERT
uintx VirtualSpaceNode::container_count_slow() {
uintx count = 0;
Metachunk* chunk = first_chunk();
Metachunk* invalid_chunk = (Metachunk*) top();
while (chunk < invalid_chunk ) {
MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();
do_verify_chunk(chunk);
// Don't count the chunks on the free lists. Those are
// still part of the VirtualSpaceNode but not currently
// counted.
if (!chunk->is_tagged_free()) {
count++;
}
chunk = (Metachunk*) next;
}
return count;
}
#endif
#ifdef ASSERT
// Verify counters, all chunks in this list node and the occupancy map.
void VirtualSpaceNode::verify() {
uintx num_in_use_chunks = 0;
Metachunk* chunk = first_chunk();
Metachunk* invalid_chunk = (Metachunk*) top();
// Iterate the chunks in this node and verify each chunk.
while (chunk < invalid_chunk ) {
DEBUG_ONLY(do_verify_chunk(chunk);)
if (!chunk->is_tagged_free()) {
num_in_use_chunks ++;
}
MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();
chunk = (Metachunk*) next;
}
assert(_container_count == num_in_use_chunks, "Container count mismatch (real: " UINTX_FORMAT
", counter: " UINTX_FORMAT ".", num_in_use_chunks, _container_count);
// Also verify the occupancy map.
occupancy_map()->verify(this->bottom(), this->top());
}
#endif // ASSERT
#ifdef ASSERT
// Verify that all free chunks in this node are ideally merged
// (there not should be multiple small chunks where a large chunk could exist.)
void VirtualSpaceNode::verify_free_chunks_are_ideally_merged() {
Metachunk* chunk = first_chunk();
Metachunk* invalid_chunk = (Metachunk*) top();
// Shorthands.
const size_t size_med = (is_class() ? ClassMediumChunk : MediumChunk) * BytesPerWord;
const size_t size_small = (is_class() ? ClassSmallChunk : SmallChunk) * BytesPerWord;
int num_free_chunks_since_last_med_boundary = -1;
int num_free_chunks_since_last_small_boundary = -1;
while (chunk < invalid_chunk ) {
// Test for missed chunk merge opportunities: count number of free chunks since last chunk boundary.
// Reset the counter when encountering a non-free chunk.
if (chunk->get_chunk_type() != HumongousIndex) {
if (chunk->is_tagged_free()) {
// Count successive free, non-humongous chunks.
if (is_aligned(chunk, size_small)) {
assert(num_free_chunks_since_last_small_boundary <= 1,
"Missed chunk merge opportunity at " PTR_FORMAT " for chunk size " SIZE_FORMAT_HEX ".", p2i(chunk) - size_small, size_small);
num_free_chunks_since_last_small_boundary = 0;
} else if (num_free_chunks_since_last_small_boundary != -1) {
num_free_chunks_since_last_small_boundary ++;
}
if (is_aligned(chunk, size_med)) {
assert(num_free_chunks_since_last_med_boundary <= 1,
"Missed chunk merge opportunity at " PTR_FORMAT " for chunk size " SIZE_FORMAT_HEX ".", p2i(chunk) - size_med, size_med);
num_free_chunks_since_last_med_boundary = 0;
} else if (num_free_chunks_since_last_med_boundary != -1) {
num_free_chunks_since_last_med_boundary ++;
}
} else {
// Encountering a non-free chunk, reset counters.
num_free_chunks_since_last_med_boundary = -1;
num_free_chunks_since_last_small_boundary = -1;
}
} else {
// One cannot merge areas with a humongous chunk in the middle. Reset counters.
num_free_chunks_since_last_med_boundary = -1;
num_free_chunks_since_last_small_boundary = -1;
}
MetaWord* next = ((MetaWord*)chunk) + chunk->word_size();
chunk = (Metachunk*) next;
}
}
#endif // ASSERT
// List of VirtualSpaces for metadata allocation.
class VirtualSpaceList : public CHeapObj<mtClass> {
friend class VirtualSpaceNode;
enum VirtualSpaceSizes {
VirtualSpaceSize = 256 * K
};
// Head of the list
VirtualSpaceNode* _virtual_space_list;
// virtual space currently being used for allocations
VirtualSpaceNode* _current_virtual_space;
// Is this VirtualSpaceList used for the compressed class space
bool _is_class;
// Sum of reserved and committed memory in the virtual spaces
size_t _reserved_words;
size_t _committed_words;
// Number of virtual spaces
size_t _virtual_space_count;
~VirtualSpaceList();
VirtualSpaceNode* virtual_space_list() const { return _virtual_space_list; }
void set_virtual_space_list(VirtualSpaceNode* v) {
_virtual_space_list = v;
}
void set_current_virtual_space(VirtualSpaceNode* v) {
_current_virtual_space = v;
}
void link_vs(VirtualSpaceNode* new_entry);
// Get another virtual space and add it to the list. This
// is typically prompted by a failed attempt to allocate a chunk
// and is typically followed by the allocation of a chunk.
bool create_new_virtual_space(size_t vs_word_size);
// Chunk up the unused committed space in the current
// virtual space and add the chunks to the free list.
void retire_current_virtual_space();
public:
VirtualSpaceList(size_t word_size);
VirtualSpaceList(ReservedSpace rs);
size_t free_bytes();
Metachunk* get_new_chunk(size_t chunk_word_size,
size_t suggested_commit_granularity);
bool expand_node_by(VirtualSpaceNode* node,
size_t min_words,
size_t preferred_words);
bool expand_by(size_t min_words,
size_t preferred_words);
VirtualSpaceNode* current_virtual_space() {
return _current_virtual_space;
}
bool is_class() const { return _is_class; }
bool initialization_succeeded() { return _virtual_space_list != NULL; }
size_t reserved_words() { return _reserved_words; }
size_t reserved_bytes() { return reserved_words() * BytesPerWord; }
size_t committed_words() { return _committed_words; }
size_t committed_bytes() { return committed_words() * BytesPerWord; }
void inc_reserved_words(size_t v);
void dec_reserved_words(size_t v);
void inc_committed_words(size_t v);
void dec_committed_words(size_t v);
void inc_virtual_space_count();
void dec_virtual_space_count();
bool contains(const void* ptr);
// Unlink empty VirtualSpaceNodes and free it.
void purge(ChunkManager* chunk_manager);
void print_on(outputStream* st) const { print_on(st, K); }
void print_on(outputStream* st, size_t scale) const;
void print_map(outputStream* st) const;
class VirtualSpaceListIterator : public StackObj {
VirtualSpaceNode* _virtual_spaces;
public:
VirtualSpaceListIterator(VirtualSpaceNode* virtual_spaces) :
_virtual_spaces(virtual_spaces) {}
bool repeat() {
return _virtual_spaces != NULL;
}
VirtualSpaceNode* get_next() {
VirtualSpaceNode* result = _virtual_spaces;
if (_virtual_spaces != NULL) {
_virtual_spaces = _virtual_spaces->next();
}
return result;
}
};
};
class Metadebug : AllStatic {
// Debugging support for Metaspaces
static int _allocation_fail_alot_count;
public:
static void init_allocation_fail_alot_count();
#ifdef ASSERT
static bool test_metadata_failure();
#endif
};
int Metadebug::_allocation_fail_alot_count = 0;
// SpaceManager - used by Metaspace to handle allocations
class SpaceManager : public CHeapObj<mtClass> {
friend class ClassLoaderMetaspace;
friend class Metadebug;
private:
// protects allocations
Mutex* const _lock;
// Type of metadata allocated.
const Metaspace::MetadataType _mdtype;
// Type of metaspace
const Metaspace::MetaspaceType _space_type;
// List of chunks in use by this SpaceManager. Allocations
// are done from the current chunk. The list is used for deallocating
// chunks when the SpaceManager is freed.
Metachunk* _chunk_list;
Metachunk* _current_chunk;
// Maximum number of small chunks to allocate to a SpaceManager
static uint const _small_chunk_limit;
// Maximum number of specialize chunks to allocate for anonymous and delegating
// metadata space to a SpaceManager
static uint const _anon_and_delegating_metadata_specialize_chunk_limit;
// Some running counters, but lets keep their number small to not add to much to
// the per-classloader footprint.
// Note: capacity = used + free + waste + overhead. We do not keep running counters for
// free and waste. Their sum can be deduced from the three other values.
size_t _overhead_words;
size_t _capacity_words;
size_t _used_words;
uintx _num_chunks_by_type[NumberOfInUseLists];
// Free lists of blocks are per SpaceManager since they
// are assumed to be in chunks in use by the SpaceManager
// and all chunks in use by a SpaceManager are freed when
// the class loader using the SpaceManager is collected.
BlockFreelist* _block_freelists;
private:
// Accessors
Metachunk* chunk_list() const { return _chunk_list; }
BlockFreelist* block_freelists() const { return _block_freelists; }
Metaspace::MetadataType mdtype() { return _mdtype; }
VirtualSpaceList* vs_list() const { return Metaspace::get_space_list(_mdtype); }
ChunkManager* chunk_manager() const { return Metaspace::get_chunk_manager(_mdtype); }
Metachunk* current_chunk() const { return _current_chunk; }
void set_current_chunk(Metachunk* v) {
_current_chunk = v;
}
Metachunk* find_current_chunk(size_t word_size);
// Add chunk to the list of chunks in use
void add_chunk(Metachunk* v, bool make_current);
void retire_current_chunk();
Mutex* lock() const { return _lock; }
// Adds to the given statistic object. Expects to be locked with lock().
void add_to_statistics_locked(SpaceManagerStatistics* out) const;
// Verify internal counters against the current state. Expects to be locked with lock().
DEBUG_ONLY(void verify_metrics_locked() const;)
public:
SpaceManager(Metaspace::MetadataType mdtype,
Metaspace::MetaspaceType space_type,
Mutex* lock);
~SpaceManager();
enum ChunkMultiples {
MediumChunkMultiple = 4
};
static size_t specialized_chunk_size(bool is_class) { return is_class ? ClassSpecializedChunk : SpecializedChunk; }
static size_t small_chunk_size(bool is_class) { return is_class ? ClassSmallChunk : SmallChunk; }
static size_t medium_chunk_size(bool is_class) { return is_class ? ClassMediumChunk : MediumChunk; }
static size_t smallest_chunk_size(bool is_class) { return specialized_chunk_size(is_class); }
// Accessors
bool is_class() const { return _mdtype == Metaspace::ClassType; }
size_t specialized_chunk_size() const { return specialized_chunk_size(is_class()); }
size_t small_chunk_size() const { return small_chunk_size(is_class()); }
size_t medium_chunk_size() const { return medium_chunk_size(is_class()); }
size_t smallest_chunk_size() const { return smallest_chunk_size(is_class()); }
size_t medium_chunk_bunch() const { return medium_chunk_size() * MediumChunkMultiple; }
bool is_humongous(size_t word_size) { return word_size > medium_chunk_size(); }
size_t capacity_words() const { return _capacity_words; }
size_t used_words() const { return _used_words; }
size_t overhead_words() const { return _overhead_words; }
// Adjust local, global counters after a new chunk has been added.
void account_for_new_chunk(const Metachunk* new_chunk);
// Adjust local, global counters after space has been allocated from the current chunk.
void account_for_allocation(size_t words);
// Adjust global counters just before the SpaceManager dies, after all its chunks
// have been returned to the freelist.
void account_for_spacemanager_death();
// Adjust the initial chunk size to match one of the fixed chunk list sizes,
// or return the unadjusted size if the requested size is humongous.
static size_t adjust_initial_chunk_size(size_t requested, bool is_class_space);
size_t adjust_initial_chunk_size(size_t requested) const;
// Get the initial chunks size for this metaspace type.
size_t get_initial_chunk_size(Metaspace::MetaspaceType type) const;
// Todo: remove this once we have counters by chunk type.
uintx num_chunks_by_type(ChunkIndex chunk_type) const { return _num_chunks_by_type[chunk_type]; }
Metachunk* get_new_chunk(size_t chunk_word_size);
// Block allocation and deallocation.
// Allocates a block from the current chunk
MetaWord* allocate(size_t word_size);
// Helper for allocations
MetaWord* allocate_work(size_t word_size);
// Returns a block to the per manager freelist
void deallocate(MetaWord* p, size_t word_size);
// Based on the allocation size and a minimum chunk size,
// returned chunk size (for expanding space for chunk allocation).
size_t calc_chunk_size(size_t allocation_word_size);
// Called when an allocation from the current chunk fails.
// Gets a new chunk (may require getting a new virtual space),
// and allocates from that chunk.
MetaWord* grow_and_allocate(size_t word_size);
// Notify memory usage to MemoryService.
void track_metaspace_memory_usage();
// debugging support.
void print_on(outputStream* st) const;
void locked_print_chunks_in_use_on(outputStream* st) const;
void verify();
void verify_chunk_size(Metachunk* chunk);
// This adjusts the size given to be greater than the minimum allocation size in
// words for data in metaspace. Esentially the minimum size is currently 3 words.
size_t get_allocation_word_size(size_t word_size) {
size_t byte_size = word_size * BytesPerWord;
size_t raw_bytes_size = MAX2(byte_size, sizeof(Metablock));
raw_bytes_size = align_up(raw_bytes_size, Metachunk::object_alignment());
size_t raw_word_size = raw_bytes_size / BytesPerWord;
assert(raw_word_size * BytesPerWord == raw_bytes_size, "Size problem");
return raw_word_size;
}
// Adds to the given statistic object.
void add_to_statistics(SpaceManagerStatistics* out) const;
// Verify internal counters against the current state.
DEBUG_ONLY(void verify_metrics() const;)
};
uint const SpaceManager::_small_chunk_limit = 4;
uint const SpaceManager::_anon_and_delegating_metadata_specialize_chunk_limit = 4;
void VirtualSpaceNode::inc_container_count() {
assert_lock_strong(MetaspaceExpand_lock);
_container_count++;
}
void VirtualSpaceNode::dec_container_count() {
assert_lock_strong(MetaspaceExpand_lock);
_container_count--;
}
#ifdef ASSERT
void VirtualSpaceNode::verify_container_count() {
assert(_container_count == container_count_slow(),
"Inconsistency in container_count _container_count " UINTX_FORMAT
" container_count_slow() " UINTX_FORMAT, _container_count, container_count_slow());
}
#endif
// BlockFreelist methods
BlockFreelist::BlockFreelist() : _dictionary(new BlockTreeDictionary()), _small_blocks(NULL) {}
BlockFreelist::~BlockFreelist() {
delete _dictionary;
if (_small_blocks != NULL) {
delete _small_blocks;
}
}
void BlockFreelist::return_block(MetaWord* p, size_t word_size) {
assert(word_size >= SmallBlocks::small_block_min_size(), "never return dark matter");
Metablock* free_chunk = ::new (p) Metablock(word_size);
if (word_size < SmallBlocks::small_block_max_size()) {
small_blocks()->return_block(free_chunk, word_size);
} else {
dictionary()->return_chunk(free_chunk);
}
log_trace(gc, metaspace, freelist, blocks)("returning block at " INTPTR_FORMAT " size = "
SIZE_FORMAT, p2i(free_chunk), word_size);
}
MetaWord* BlockFreelist::get_block(size_t word_size) {
assert(word_size >= SmallBlocks::small_block_min_size(), "never get dark matter");
// Try small_blocks first.
if (word_size < SmallBlocks::small_block_max_size()) {
// Don't create small_blocks() until needed. small_blocks() allocates the small block list for
// this space manager.
MetaWord* new_block = (MetaWord*) small_blocks()->get_block(word_size);
if (new_block != NULL) {
log_trace(gc, metaspace, freelist, blocks)("getting block at " INTPTR_FORMAT " size = " SIZE_FORMAT,
p2i(new_block), word_size);
return new_block;
}
}
if (word_size < BlockFreelist::min_dictionary_size()) {
// If allocation in small blocks fails, this is Dark Matter. Too small for dictionary.
return NULL;
}
Metablock* free_block = dictionary()->get_chunk(word_size);
if (free_block == NULL) {
return NULL;
}
const size_t block_size = free_block->size();
if (block_size > WasteMultiplier * word_size) {
return_block((MetaWord*)free_block, block_size);
return NULL;
}
MetaWord* new_block = (MetaWord*)free_block;
assert(block_size >= word_size, "Incorrect size of block from freelist");
const size_t unused = block_size - word_size;
if (unused >= SmallBlocks::small_block_min_size()) {
return_block(new_block + word_size, unused);
}
log_trace(gc, metaspace, freelist, blocks)("getting block at " INTPTR_FORMAT " size = " SIZE_FORMAT,
p2i(new_block), word_size);
return new_block;
}
void BlockFreelist::print_on(outputStream* st) const {
dictionary()->print_free_lists(st);
if (_small_blocks != NULL) {
_small_blocks->print_on(st);
}
}
// VirtualSpaceNode methods
VirtualSpaceNode::~VirtualSpaceNode() {
_rs.release();
if (_occupancy_map != NULL) {
delete _occupancy_map;
}
#ifdef ASSERT
size_t word_size = sizeof(*this) / BytesPerWord;
Copy::fill_to_words((HeapWord*) this, word_size, 0xf1f1f1f1);
#endif
}
size_t VirtualSpaceNode::used_words_in_vs() const {
return pointer_delta(top(), bottom(), sizeof(MetaWord));
}
// Space committed in the VirtualSpace
size_t VirtualSpaceNode::capacity_words_in_vs() const {
return pointer_delta(end(), bottom(), sizeof(MetaWord));
}
size_t VirtualSpaceNode::free_words_in_vs() const {
return pointer_delta(end(), top(), sizeof(MetaWord));
}
// Given an address larger than top(), allocate padding chunks until top is at the given address.
void VirtualSpaceNode::allocate_padding_chunks_until_top_is_at(MetaWord* target_top) {
assert(target_top > top(), "Sanity");
// Padding chunks are added to the freelist.
ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(this->is_class());
// shorthands
const size_t spec_word_size = chunk_manager->specialized_chunk_word_size();
const size_t small_word_size = chunk_manager->small_chunk_word_size();
const size_t med_word_size = chunk_manager->medium_chunk_word_size();
while (top() < target_top) {
// We could make this coding more generic, but right now we only deal with two possible chunk sizes
// for padding chunks, so it is not worth it.
size_t padding_chunk_word_size = small_word_size;
if (is_aligned(top(), small_word_size * sizeof(MetaWord)) == false) {
assert_is_aligned(top(), spec_word_size * sizeof(MetaWord)); // Should always hold true.
padding_chunk_word_size = spec_word_size;
}
MetaWord* here = top();
assert_is_aligned(here, padding_chunk_word_size * sizeof(MetaWord));
inc_top(padding_chunk_word_size);
// Create new padding chunk.
ChunkIndex padding_chunk_type = get_chunk_type_by_size(padding_chunk_word_size, is_class());
assert(padding_chunk_type == SpecializedIndex || padding_chunk_type == SmallIndex, "sanity");
Metachunk* const padding_chunk =
::new (here) Metachunk(padding_chunk_type, is_class(), padding_chunk_word_size, this);
assert(padding_chunk == (Metachunk*)here, "Sanity");
DEBUG_ONLY(padding_chunk->set_origin(origin_pad);)
log_trace(gc, metaspace, freelist)("Created padding chunk in %s at "
PTR_FORMAT ", size " SIZE_FORMAT_HEX ".",
(is_class() ? "class space " : "metaspace"),
p2i(padding_chunk), padding_chunk->word_size() * sizeof(MetaWord));
// Mark chunk start in occupancy map.
occupancy_map()->set_chunk_starts_at_address((MetaWord*)padding_chunk, true);
// Chunks are born as in-use (see MetaChunk ctor). So, before returning
// the padding chunk to its chunk manager, mark it as in use (ChunkManager
// will assert that).
do_update_in_use_info_for_chunk(padding_chunk, true);
// Return Chunk to freelist.
inc_container_count();
chunk_manager->return_single_chunk(padding_chunk);
// Please note: at this point, ChunkManager::return_single_chunk()
// may already have merged the padding chunk with neighboring chunks, so
// it may have vanished at this point. Do not reference the padding
// chunk beyond this point.
}
assert(top() == target_top, "Sanity");
} // allocate_padding_chunks_until_top_is_at()
// Allocates the chunk from the virtual space only.
// This interface is also used internally for debugging. Not all
// chunks removed here are necessarily used for allocation.
Metachunk* VirtualSpaceNode::take_from_committed(size_t chunk_word_size) {
// Non-humongous chunks are to be allocated aligned to their chunk
// size. So, start addresses of medium chunks are aligned to medium
// chunk size, those of small chunks to small chunk size and so
// forth. This facilitates merging of free chunks and reduces
// fragmentation. Chunk sizes are spec < small < medium, with each
// larger chunk size being a multiple of the next smaller chunk
// size.
// Because of this alignment, me may need to create a number of padding
// chunks. These chunks are created and added to the freelist.
// The chunk manager to which we will give our padding chunks.
ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(this->is_class());
// shorthands
const size_t spec_word_size = chunk_manager->specialized_chunk_word_size();
const size_t small_word_size = chunk_manager->small_chunk_word_size();
const size_t med_word_size = chunk_manager->medium_chunk_word_size();
assert(chunk_word_size == spec_word_size || chunk_word_size == small_word_size ||
chunk_word_size >= med_word_size, "Invalid chunk size requested.");
// Chunk alignment (in bytes) == chunk size unless humongous.
// Humongous chunks are aligned to the smallest chunk size (spec).
const size_t required_chunk_alignment = (chunk_word_size > med_word_size ?
spec_word_size : chunk_word_size) * sizeof(MetaWord);
// Do we have enough space to create the requested chunk plus
// any padding chunks needed?
MetaWord* const next_aligned =
static_cast<MetaWord*>(align_up(top(), required_chunk_alignment));
if (!is_available((next_aligned - top()) + chunk_word_size)) {
return NULL;
}
// Before allocating the requested chunk, allocate padding chunks if necessary.
// We only need to do this for small or medium chunks: specialized chunks are the
// smallest size, hence always aligned. Homungous chunks are allocated unaligned
// (implicitly, also aligned to smallest chunk size).
if ((chunk_word_size == med_word_size || chunk_word_size == small_word_size) && next_aligned > top()) {
log_trace(gc, metaspace, freelist)("Creating padding chunks in %s between %p and %p...",
(is_class() ? "class space " : "metaspace"),
top(), next_aligned);
allocate_padding_chunks_until_top_is_at(next_aligned);
// Now, top should be aligned correctly.
assert_is_aligned(top(), required_chunk_alignment);
}
// Now, top should be aligned correctly.
assert_is_aligned(top(), required_chunk_alignment);
// Bottom of the new chunk
MetaWord* chunk_limit = top();
assert(chunk_limit != NULL, "Not safe to call this method");
// The virtual spaces are always expanded by the
// commit granularity to enforce the following condition.
// Without this the is_available check will not work correctly.
assert(_virtual_space.committed_size() == _virtual_space.actual_committed_size(),
"The committed memory doesn't match the expanded memory.");
if (!is_available(chunk_word_size)) {
LogTarget(Debug, gc, metaspace, freelist) lt;
if (lt.is_enabled()) {
LogStream ls(lt);
ls.print("VirtualSpaceNode::take_from_committed() not available " SIZE_FORMAT " words ", chunk_word_size);
// Dump some information about the virtual space that is nearly full
print_on(&ls);
}
return NULL;
}
// Take the space (bump top on the current virtual space).
inc_top(chunk_word_size);
// Initialize the chunk
ChunkIndex chunk_type = get_chunk_type_by_size(chunk_word_size, is_class());
Metachunk* result = ::new (chunk_limit) Metachunk(chunk_type, is_class(), chunk_word_size, this);
assert(result == (Metachunk*)chunk_limit, "Sanity");
occupancy_map()->set_chunk_starts_at_address((MetaWord*)result, true);
do_update_in_use_info_for_chunk(result, true);
inc_container_count();
if (VerifyMetaspace) {
DEBUG_ONLY(chunk_manager->locked_verify());
DEBUG_ONLY(this->verify());
}
DEBUG_ONLY(do_verify_chunk(result));
result->inc_use_count();
return result;
}
// Expand the virtual space (commit more of the reserved space)
bool VirtualSpaceNode::expand_by(size_t min_words, size_t preferred_words) {
size_t min_bytes = min_words * BytesPerWord;
size_t preferred_bytes = preferred_words * BytesPerWord;
size_t uncommitted = virtual_space()->reserved_size() - virtual_space()->actual_committed_size();
if (uncommitted < min_bytes) {
return false;
}
size_t commit = MIN2(preferred_bytes, uncommitted);
bool result = virtual_space()->expand_by(commit, false);
if (result) {
log_trace(gc, metaspace, freelist)("Expanded %s virtual space list node by " SIZE_FORMAT " words.",
(is_class() ? "class" : "non-class"), commit);
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_committed_space_expanded));
} else {
log_trace(gc, metaspace, freelist)("Failed to expand %s virtual space list node by " SIZE_FORMAT " words.",
(is_class() ? "class" : "non-class"), commit);
}
assert(result, "Failed to commit memory");
return result;
}
Metachunk* VirtualSpaceNode::get_chunk_vs(size_t chunk_word_size) {
assert_lock_strong(MetaspaceExpand_lock);
Metachunk* result = take_from_committed(chunk_word_size);
return result;
}
bool VirtualSpaceNode::initialize() {
if (!_rs.is_reserved()) {
return false;
}
// These are necessary restriction to make sure that the virtual space always
// grows in steps of Metaspace::commit_alignment(). If both base and size are
// aligned only the middle alignment of the VirtualSpace is used.
assert_is_aligned(_rs.base(), Metaspace::commit_alignment());
assert_is_aligned(_rs.size(), Metaspace::commit_alignment());
// ReservedSpaces marked as special will have the entire memory
// pre-committed. Setting a committed size will make sure that
// committed_size and actual_committed_size agrees.
size_t pre_committed_size = _rs.special() ? _rs.size() : 0;
bool result = virtual_space()->initialize_with_granularity(_rs, pre_committed_size,
Metaspace::commit_alignment());
if (result) {
assert(virtual_space()->committed_size() == virtual_space()->actual_committed_size(),
"Checking that the pre-committed memory was registered by the VirtualSpace");
set_top((MetaWord*)virtual_space()->low());
set_reserved(MemRegion((HeapWord*)_rs.base(),
(HeapWord*)(_rs.base() + _rs.size())));
assert(reserved()->start() == (HeapWord*) _rs.base(),
"Reserved start was not set properly " PTR_FORMAT
" != " PTR_FORMAT, p2i(reserved()->start()), p2i(_rs.base()));
assert(reserved()->word_size() == _rs.size() / BytesPerWord,
"Reserved size was not set properly " SIZE_FORMAT
" != " SIZE_FORMAT, reserved()->word_size(),
_rs.size() / BytesPerWord);
}
// Initialize Occupancy Map.
const size_t smallest_chunk_size = is_class() ? ClassSpecializedChunk : SpecializedChunk;
_occupancy_map = new OccupancyMap(bottom(), reserved_words(), smallest_chunk_size);
return result;
}
void VirtualSpaceNode::print_on(outputStream* st, size_t scale) const {
size_t used_words = used_words_in_vs();
size_t commit_words = committed_words();
size_t res_words = reserved_words();
VirtualSpace* vs = virtual_space();
st->print("node @" PTR_FORMAT ": ", p2i(this));
st->print("reserved=");
print_scaled_words(st, res_words, scale);
st->print(", committed=");
print_scaled_words_and_percentage(st, commit_words, res_words, scale);
st->print(", used=");
print_scaled_words_and_percentage(st, used_words, res_words, scale);
st->cr();
st->print(" [" PTR_FORMAT ", " PTR_FORMAT ", "
PTR_FORMAT ", " PTR_FORMAT ")",
p2i(bottom()), p2i(top()), p2i(end()),
p2i(vs->high_boundary()));
}
#ifdef ASSERT
void VirtualSpaceNode::mangle() {
size_t word_size = capacity_words_in_vs();
Copy::fill_to_words((HeapWord*) low(), word_size, 0xf1f1f1f1);
}
#endif // ASSERT
// VirtualSpaceList methods
// Space allocated from the VirtualSpace
VirtualSpaceList::~VirtualSpaceList() {
VirtualSpaceListIterator iter(virtual_space_list());
while (iter.repeat()) {
VirtualSpaceNode* vsl = iter.get_next();
delete vsl;
}
}
void VirtualSpaceList::inc_reserved_words(size_t v) {
assert_lock_strong(MetaspaceExpand_lock);
_reserved_words = _reserved_words + v;
}
void VirtualSpaceList::dec_reserved_words(size_t v) {
assert_lock_strong(MetaspaceExpand_lock);
_reserved_words = _reserved_words - v;
}
#define assert_committed_below_limit() \
assert(MetaspaceUtils::committed_bytes() <= MaxMetaspaceSize, \
"Too much committed memory. Committed: " SIZE_FORMAT \
" limit (MaxMetaspaceSize): " SIZE_FORMAT, \
MetaspaceUtils::committed_bytes(), MaxMetaspaceSize);
void VirtualSpaceList::inc_committed_words(size_t v) {
assert_lock_strong(MetaspaceExpand_lock);
_committed_words = _committed_words + v;
assert_committed_below_limit();
}
void VirtualSpaceList::dec_committed_words(size_t v) {
assert_lock_strong(MetaspaceExpand_lock);
_committed_words = _committed_words - v;
assert_committed_below_limit();
}
void VirtualSpaceList::inc_virtual_space_count() {
assert_lock_strong(MetaspaceExpand_lock);
_virtual_space_count++;
}
void VirtualSpaceList::dec_virtual_space_count() {
assert_lock_strong(MetaspaceExpand_lock);
_virtual_space_count--;
}
void ChunkManager::remove_chunk(Metachunk* chunk) {
size_t word_size = chunk->word_size();
ChunkIndex index = list_index(word_size);
if (index != HumongousIndex) {
free_chunks(index)->remove_chunk(chunk);
} else {
humongous_dictionary()->remove_chunk(chunk);
}
// Chunk has been removed from the chunks free list, update counters.
account_for_removed_chunk(chunk);
}
bool ChunkManager::attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type) {
assert_lock_strong(MetaspaceExpand_lock);
assert(chunk != NULL, "invalid chunk pointer");
// Check for valid merge combinations.
assert((chunk->get_chunk_type() == SpecializedIndex &&
(target_chunk_type == SmallIndex || target_chunk_type == MediumIndex)) ||
(chunk->get_chunk_type() == SmallIndex && target_chunk_type == MediumIndex),
"Invalid chunk merge combination.");
const size_t target_chunk_word_size =
get_size_for_nonhumongous_chunktype(target_chunk_type, this->is_class());
// [ prospective merge region )
MetaWord* const p_merge_region_start =
(MetaWord*) align_down(chunk, target_chunk_word_size * sizeof(MetaWord));
MetaWord* const p_merge_region_end =
p_merge_region_start + target_chunk_word_size;
// We need the VirtualSpaceNode containing this chunk and its occupancy map.
VirtualSpaceNode* const vsn = chunk->container();
OccupancyMap* const ocmap = vsn->occupancy_map();
// The prospective chunk merge range must be completely contained by the
// committed range of the virtual space node.
if (p_merge_region_start < vsn->bottom() || p_merge_region_end > vsn->top()) {
return false;
}
// Only attempt to merge this range if at its start a chunk starts and at its end
// a chunk ends. If a chunk (can only be humongous) straddles either start or end
// of that range, we cannot merge.
if (!ocmap->chunk_starts_at_address(p_merge_region_start)) {
return false;
}
if (p_merge_region_end < vsn->top() &&
!ocmap->chunk_starts_at_address(p_merge_region_end)) {
return false;
}
// Now check if the prospective merge area contains live chunks. If it does we cannot merge.
if (ocmap->is_region_in_use(p_merge_region_start, target_chunk_word_size)) {
return false;
}
// Success! Remove all chunks in this region...
log_trace(gc, metaspace, freelist)("%s: coalescing chunks in area [%p-%p)...",
(is_class() ? "class space" : "metaspace"),
p_merge_region_start, p_merge_region_end);
const int num_chunks_removed =
remove_chunks_in_area(p_merge_region_start, target_chunk_word_size);
// ... and create a single new bigger chunk.
Metachunk* const p_new_chunk =
::new (p_merge_region_start) Metachunk(target_chunk_type, is_class(), target_chunk_word_size, vsn);
assert(p_new_chunk == (Metachunk*)p_merge_region_start, "Sanity");
p_new_chunk->set_origin(origin_merge);
log_trace(gc, metaspace, freelist)("%s: created coalesced chunk at %p, size " SIZE_FORMAT_HEX ".",
(is_class() ? "class space" : "metaspace"),
p_new_chunk, p_new_chunk->word_size() * sizeof(MetaWord));
// Fix occupancy map: remove old start bits of the small chunks and set new start bit.
ocmap->wipe_chunk_start_bits_in_region(p_merge_region_start, target_chunk_word_size);
ocmap->set_chunk_starts_at_address(p_merge_region_start, true);
// Mark chunk as free. Note: it is not necessary to update the occupancy
// map in-use map, because the old chunks were also free, so nothing
// should have changed.
p_new_chunk->set_is_tagged_free(true);
// Add new chunk to its freelist.
ChunkList* const list = free_chunks(target_chunk_type);
list->return_chunk_at_head(p_new_chunk);
// And adjust ChunkManager:: _free_chunks_count (_free_chunks_total
// should not have changed, because the size of the space should be the same)
_free_chunks_count -= num_chunks_removed;
_free_chunks_count ++;
// VirtualSpaceNode::container_count does not have to be modified:
// it means "number of active (non-free) chunks", so merging free chunks
// should not affect that count.
// At the end of a chunk merge, run verification tests.
if (VerifyMetaspace) {
DEBUG_ONLY(this->locked_verify());
DEBUG_ONLY(vsn->verify());
}
return true;
}
// Remove all chunks in the given area - the chunks are supposed to be free -
// from their corresponding freelists. Mark them as invalid.
// - This does not correct the occupancy map.
// - This does not adjust the counters in ChunkManager.
// - Does not adjust container count counter in containing VirtualSpaceNode
// Returns number of chunks removed.
int ChunkManager::remove_chunks_in_area(MetaWord* p, size_t word_size) {
assert(p != NULL && word_size > 0, "Invalid range.");
const size_t smallest_chunk_size = get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class());
assert_is_aligned(word_size, smallest_chunk_size);
Metachunk* const start = (Metachunk*) p;
const Metachunk* const end = (Metachunk*)(p + word_size);
Metachunk* cur = start;
int num_removed = 0;
while (cur < end) {
Metachunk* next = (Metachunk*)(((MetaWord*)cur) + cur->word_size());
DEBUG_ONLY(do_verify_chunk(cur));
assert(cur->get_chunk_type() != HumongousIndex, "Unexpected humongous chunk found at %p.", cur);
assert(cur->is_tagged_free(), "Chunk expected to be free (%p)", cur);
log_trace(gc, metaspace, freelist)("%s: removing chunk %p, size " SIZE_FORMAT_HEX ".",
(is_class() ? "class space" : "metaspace"),
cur, cur->word_size() * sizeof(MetaWord));
cur->remove_sentinel();
// Note: cannot call ChunkManager::remove_chunk, because that
// modifies the counters in ChunkManager, which we do not want. So
// we call remove_chunk on the freelist directly (see also the
// splitting function which does the same).
ChunkList* const list = free_chunks(list_index(cur->word_size()));
list->remove_chunk(cur);
num_removed ++;
cur = next;
}
return num_removed;
}
// Walk the list of VirtualSpaceNodes and delete
// nodes with a 0 container_count. Remove Metachunks in
// the node from their respective freelists.
void VirtualSpaceList::purge(ChunkManager* chunk_manager) {
assert(SafepointSynchronize::is_at_safepoint(), "must be called at safepoint for contains to work");
assert_lock_strong(MetaspaceExpand_lock);
// Don't use a VirtualSpaceListIterator because this
// list is being changed and a straightforward use of an iterator is not safe.
VirtualSpaceNode* purged_vsl = NULL;
VirtualSpaceNode* prev_vsl = virtual_space_list();
VirtualSpaceNode* next_vsl = prev_vsl;
while (next_vsl != NULL) {
VirtualSpaceNode* vsl = next_vsl;
DEBUG_ONLY(vsl->verify_container_count();)
next_vsl = vsl->next();
// Don't free the current virtual space since it will likely
// be needed soon.
if (vsl->container_count() == 0 && vsl != current_virtual_space()) {
log_trace(gc, metaspace, freelist)("Purging VirtualSpaceNode " PTR_FORMAT " (capacity: " SIZE_FORMAT
", used: " SIZE_FORMAT ").", p2i(vsl), vsl->capacity_words_in_vs(), vsl->used_words_in_vs());
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_vsnodes_purged));
// Unlink it from the list
if (prev_vsl == vsl) {
// This is the case of the current node being the first node.
assert(vsl == virtual_space_list(), "Expected to be the first node");
set_virtual_space_list(vsl->next());
} else {
prev_vsl->set_next(vsl->next());
}
vsl->purge(chunk_manager);
dec_reserved_words(vsl->reserved_words());
dec_committed_words(vsl->committed_words());
dec_virtual_space_count();
purged_vsl = vsl;
delete vsl;
} else {
prev_vsl = vsl;
}
}
#ifdef ASSERT
if (purged_vsl != NULL) {
// List should be stable enough to use an iterator here.
VirtualSpaceListIterator iter(virtual_space_list());
while (iter.repeat()) {
VirtualSpaceNode* vsl = iter.get_next();
assert(vsl != purged_vsl, "Purge of vsl failed");
}
}
#endif
}
// This function looks at the mmap regions in the metaspace without locking.
// The chunks are added with store ordering and not deleted except for at
// unloading time during a safepoint.
bool VirtualSpaceList::contains(const void* ptr) {
// List should be stable enough to use an iterator here because removing virtual
// space nodes is only allowed at a safepoint.
VirtualSpaceListIterator iter(virtual_space_list());
while (iter.repeat()) {
VirtualSpaceNode* vsn = iter.get_next();
if (vsn->contains(ptr)) {
return true;
}
}
return false;
}
void VirtualSpaceList::retire_current_virtual_space() {
assert_lock_strong(MetaspaceExpand_lock);
VirtualSpaceNode* vsn = current_virtual_space();
ChunkManager* cm = is_class() ? Metaspace::chunk_manager_class() :
Metaspace::chunk_manager_metadata();
vsn->retire(cm);
}
void VirtualSpaceNode::retire(ChunkManager* chunk_manager) {
DEBUG_ONLY(verify_container_count();)
assert(this->is_class() == chunk_manager->is_class(), "Wrong ChunkManager?");
for (int i = (int)MediumIndex; i >= (int)ZeroIndex; --i) {
ChunkIndex index = (ChunkIndex)i;
size_t chunk_size = chunk_manager->size_by_index(index);
while (free_words_in_vs() >= chunk_size) {
Metachunk* chunk = get_chunk_vs(chunk_size);
// Chunk will be allocated aligned, so allocation may require
// additional padding chunks. That may cause above allocation to
// fail. Just ignore the failed allocation and continue with the
// next smaller chunk size. As the VirtualSpaceNode comitted
// size should be a multiple of the smallest chunk size, we
// should always be able to fill the VirtualSpace completely.
if (chunk == NULL) {
break;
}
chunk_manager->return_single_chunk(chunk);
}
DEBUG_ONLY(verify_container_count();)
}
assert(free_words_in_vs() == 0, "should be empty now");
}
VirtualSpaceList::VirtualSpaceList(size_t word_size) :
_is_class(false),
_virtual_space_list(NULL),
_current_virtual_space(NULL),
_reserved_words(0),
_committed_words(0),
_virtual_space_count(0) {
MutexLockerEx cl(MetaspaceExpand_lock,
Mutex::_no_safepoint_check_flag);
create_new_virtual_space(word_size);
}
VirtualSpaceList::VirtualSpaceList(ReservedSpace rs) :
_is_class(true),
_virtual_space_list(NULL),
_current_virtual_space(NULL),
_reserved_words(0),
_committed_words(0),
_virtual_space_count(0) {
MutexLockerEx cl(MetaspaceExpand_lock,
Mutex::_no_safepoint_check_flag);
VirtualSpaceNode* class_entry = new VirtualSpaceNode(is_class(), rs);
bool succeeded = class_entry->initialize();
if (succeeded) {
link_vs(class_entry);
}
}
size_t VirtualSpaceList::free_bytes() {
return current_virtual_space()->free_words_in_vs() * BytesPerWord;
}
// Allocate another meta virtual space and add it to the list.
bool VirtualSpaceList::create_new_virtual_space(size_t vs_word_size) {
assert_lock_strong(MetaspaceExpand_lock);
if (is_class()) {
assert(false, "We currently don't support more than one VirtualSpace for"
" the compressed class space. The initialization of the"
" CCS uses another code path and should not hit this path.");
return false;
}
if (vs_word_size == 0) {
assert(false, "vs_word_size should always be at least _reserve_alignment large.");
return false;
}
// Reserve the space
size_t vs_byte_size = vs_word_size * BytesPerWord;
assert_is_aligned(vs_byte_size, Metaspace::reserve_alignment());
// Allocate the meta virtual space and initialize it.
VirtualSpaceNode* new_entry = new VirtualSpaceNode(is_class(), vs_byte_size);
if (!new_entry->initialize()) {
delete new_entry;
return false;
} else {
assert(new_entry->reserved_words() == vs_word_size,
"Reserved memory size differs from requested memory size");
// ensure lock-free iteration sees fully initialized node
OrderAccess::storestore();
link_vs(new_entry);
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_vsnodes_created));
return true;
}
}
void VirtualSpaceList::link_vs(VirtualSpaceNode* new_entry) {
if (virtual_space_list() == NULL) {
set_virtual_space_list(new_entry);
} else {
current_virtual_space()->set_next(new_entry);
}
set_current_virtual_space(new_entry);
inc_reserved_words(new_entry->reserved_words());
inc_committed_words(new_entry->committed_words());
inc_virtual_space_count();
#ifdef ASSERT
new_entry->mangle();
#endif
LogTarget(Trace, gc, metaspace) lt;
if (lt.is_enabled()) {
LogStream ls(lt);
VirtualSpaceNode* vsl = current_virtual_space();
ResourceMark rm;
vsl->print_on(&ls);
}
}
bool VirtualSpaceList::expand_node_by(VirtualSpaceNode* node,
size_t min_words,
size_t preferred_words) {
size_t before = node->committed_words();
bool result = node->expand_by(min_words, preferred_words);
size_t after = node->committed_words();
// after and before can be the same if the memory was pre-committed.
assert(after >= before, "Inconsistency");
inc_committed_words(after - before);
return result;
}
bool VirtualSpaceList::expand_by(size_t min_words, size_t preferred_words) {
assert_is_aligned(min_words, Metaspace::commit_alignment_words());
assert_is_aligned(preferred_words, Metaspace::commit_alignment_words());
assert(min_words <= preferred_words, "Invalid arguments");
const char* const class_or_not = (is_class() ? "class" : "non-class");
if (!MetaspaceGC::can_expand(min_words, this->is_class())) {
log_trace(gc, metaspace, freelist)("Cannot expand %s virtual space list.",
class_or_not);
return false;
}
size_t allowed_expansion_words = MetaspaceGC::allowed_expansion();
if (allowed_expansion_words < min_words) {
log_trace(gc, metaspace, freelist)("Cannot expand %s virtual space list (must try gc first).",
class_or_not);
return false;
}
size_t max_expansion_words = MIN2(preferred_words, allowed_expansion_words);
// Commit more memory from the the current virtual space.
bool vs_expanded = expand_node_by(current_virtual_space(),
min_words,
max_expansion_words);
if (vs_expanded) {
log_trace(gc, metaspace, freelist)("Expanded %s virtual space list.",
class_or_not);
return true;
}
log_trace(gc, metaspace, freelist)("%s virtual space list: retire current node.",
class_or_not);
retire_current_virtual_space();
// Get another virtual space.
size_t grow_vs_words = MAX2((size_t)VirtualSpaceSize, preferred_words);
grow_vs_words = align_up(grow_vs_words, Metaspace::reserve_alignment_words());
if (create_new_virtual_space(grow_vs_words)) {
if (current_virtual_space()->is_pre_committed()) {
// The memory was pre-committed, so we are done here.
assert(min_words <= current_virtual_space()->committed_words(),
"The new VirtualSpace was pre-committed, so it"
"should be large enough to fit the alloc request.");
return true;
}
return expand_node_by(current_virtual_space(),
min_words,
max_expansion_words);
}
return false;
}
// Given a chunk, calculate the largest possible padding space which
// could be required when allocating it.
static size_t largest_possible_padding_size_for_chunk(size_t chunk_word_size, bool is_class) {
const ChunkIndex chunk_type = get_chunk_type_by_size(chunk_word_size, is_class);
if (chunk_type != HumongousIndex) {
// Normal, non-humongous chunks are allocated at chunk size
// boundaries, so the largest padding space required would be that
// minus the smallest chunk size.
const size_t smallest_chunk_size = is_class ? ClassSpecializedChunk : SpecializedChunk;
return chunk_word_size - smallest_chunk_size;
} else {
// Humongous chunks are allocated at smallest-chunksize
// boundaries, so there is no padding required.
return 0;
}
}
Metachunk* VirtualSpaceList::get_new_chunk(size_t chunk_word_size, size_t suggested_commit_granularity) {
// Allocate a chunk out of the current virtual space.
Metachunk* next = current_virtual_space()->get_chunk_vs(chunk_word_size);
if (next != NULL) {
return next;
}
// The expand amount is currently only determined by the requested sizes
// and not how much committed memory is left in the current virtual space.
// We must have enough space for the requested size and any
// additional reqired padding chunks.
const size_t size_for_padding = largest_possible_padding_size_for_chunk(chunk_word_size, this->is_class());
size_t min_word_size = align_up(chunk_word_size + size_for_padding, Metaspace::commit_alignment_words());
size_t preferred_word_size = align_up(suggested_commit_granularity, Metaspace::commit_alignment_words());
if (min_word_size >= preferred_word_size) {
// Can happen when humongous chunks are allocated.
preferred_word_size = min_word_size;
}
bool expanded = expand_by(min_word_size, preferred_word_size);
if (expanded) {
next = current_virtual_space()->get_chunk_vs(chunk_word_size);
assert(next != NULL, "The allocation was expected to succeed after the expansion");
}
return next;
}
void VirtualSpaceList::print_on(outputStream* st, size_t scale) const {
st->print_cr(SIZE_FORMAT " nodes, current node: " PTR_FORMAT,
_virtual_space_count, p2i(_current_virtual_space));
VirtualSpaceListIterator iter(virtual_space_list());
while (iter.repeat()) {
st->cr();
VirtualSpaceNode* node = iter.get_next();
node->print_on(st, scale);
}
}
void VirtualSpaceList::print_map(outputStream* st) const {
VirtualSpaceNode* list = virtual_space_list();
VirtualSpaceListIterator iter(list);
unsigned i = 0;
while (iter.repeat()) {
st->print_cr("Node %u:", i);
VirtualSpaceNode* node = iter.get_next();
node->print_map(st, this->is_class());
i ++;
}
}
// MetaspaceGC methods
// VM_CollectForMetadataAllocation is the vm operation used to GC.
// Within the VM operation after the GC the attempt to allocate the metadata
// should succeed. If the GC did not free enough space for the metaspace
// allocation, the HWM is increased so that another virtualspace will be
// allocated for the metadata. With perm gen the increase in the perm
// gen had bounds, MinMetaspaceExpansion and MaxMetaspaceExpansion. The
// metaspace policy uses those as the small and large steps for the HWM.
//
// After the GC the compute_new_size() for MetaspaceGC is called to
// resize the capacity of the metaspaces. The current implementation
// is based on the flags MinMetaspaceFreeRatio and MaxMetaspaceFreeRatio used
// to resize the Java heap by some GC's. New flags can be implemented
// if really needed. MinMetaspaceFreeRatio is used to calculate how much
// free space is desirable in the metaspace capacity to decide how much
// to increase the HWM. MaxMetaspaceFreeRatio is used to decide how much
// free space is desirable in the metaspace capacity before decreasing
// the HWM.
// Calculate the amount to increase the high water mark (HWM).
// Increase by a minimum amount (MinMetaspaceExpansion) so that
// another expansion is not requested too soon. If that is not
// enough to satisfy the allocation, increase by MaxMetaspaceExpansion.
// If that is still not enough, expand by the size of the allocation
// plus some.
size_t MetaspaceGC::delta_capacity_until_GC(size_t bytes) {
size_t min_delta = MinMetaspaceExpansion;
size_t max_delta = MaxMetaspaceExpansion;
size_t delta = align_up(bytes, Metaspace::commit_alignment());
if (delta <= min_delta) {
delta = min_delta;
} else if (delta <= max_delta) {
// Don't want to hit the high water mark on the next
// allocation so make the delta greater than just enough
// for this allocation.
delta = max_delta;
} else {
// This allocation is large but the next ones are probably not
// so increase by the minimum.
delta = delta + min_delta;
}
assert_is_aligned(delta, Metaspace::commit_alignment());
return delta;
}
size_t MetaspaceGC::capacity_until_GC() {
size_t value = OrderAccess::load_acquire(&_capacity_until_GC);
assert(value >= MetaspaceSize, "Not initialized properly?");
return value;
}
bool MetaspaceGC::inc_capacity_until_GC(size_t v, size_t* new_cap_until_GC, size_t* old_cap_until_GC) {
assert_is_aligned(v, Metaspace::commit_alignment());
intptr_t capacity_until_GC = _capacity_until_GC;
intptr_t new_value = capacity_until_GC + v;
if (new_value < capacity_until_GC) {
// The addition wrapped around, set new_value to aligned max value.
new_value = align_down(max_uintx, Metaspace::commit_alignment());
}
intptr_t expected = _capacity_until_GC;
intptr_t actual = Atomic::cmpxchg(new_value, &_capacity_until_GC, expected);
if (expected != actual) {
return false;
}
if (new_cap_until_GC != NULL) {
*new_cap_until_GC = new_value;
}
if (old_cap_until_GC != NULL) {
*old_cap_until_GC = capacity_until_GC;
}
return true;
}
size_t MetaspaceGC::dec_capacity_until_GC(size_t v) {
assert_is_aligned(v, Metaspace::commit_alignment());
return (size_t)Atomic::sub((intptr_t)v, &_capacity_until_GC);
}
void MetaspaceGC::initialize() {
// Set the high-water mark to MaxMetapaceSize during VM initializaton since
// we can't do a GC during initialization.
_capacity_until_GC = MaxMetaspaceSize;
}
void MetaspaceGC::post_initialize() {
// Reset the high-water mark once the VM initialization is done.
_capacity_until_GC = MAX2(MetaspaceUtils::committed_bytes(), MetaspaceSize);
}
bool MetaspaceGC::can_expand(size_t word_size, bool is_class) {
// Check if the compressed class space is full.
if (is_class && Metaspace::using_class_space()) {
size_t class_committed = MetaspaceUtils::committed_bytes(Metaspace::ClassType);
if (class_committed + word_size * BytesPerWord > CompressedClassSpaceSize) {
log_trace(gc, metaspace, freelist)("Cannot expand %s metaspace by " SIZE_FORMAT " words (CompressedClassSpaceSize = " SIZE_FORMAT " words)",
(is_class ? "class" : "non-class"), word_size, CompressedClassSpaceSize / sizeof(MetaWord));
return false;
}
}
// Check if the user has imposed a limit on the metaspace memory.
size_t committed_bytes = MetaspaceUtils::committed_bytes();
if (committed_bytes + word_size * BytesPerWord > MaxMetaspaceSize) {
log_trace(gc, metaspace, freelist)("Cannot expand %s metaspace by " SIZE_FORMAT " words (MaxMetaspaceSize = " SIZE_FORMAT " words)",
(is_class ? "class" : "non-class"), word_size, MaxMetaspaceSize / sizeof(MetaWord));
return false;
}
return true;
}
size_t MetaspaceGC::allowed_expansion() {
size_t committed_bytes = MetaspaceUtils::committed_bytes();
size_t capacity_until_gc = capacity_until_GC();
assert(capacity_until_gc >= committed_bytes,
"capacity_until_gc: " SIZE_FORMAT " < committed_bytes: " SIZE_FORMAT,
capacity_until_gc, committed_bytes);
size_t left_until_max = MaxMetaspaceSize - committed_bytes;
size_t left_until_GC = capacity_until_gc - committed_bytes;
size_t left_to_commit = MIN2(left_until_GC, left_until_max);
log_trace(gc, metaspace, freelist)("allowed expansion words: " SIZE_FORMAT
" (left_until_max: " SIZE_FORMAT ", left_until_GC: " SIZE_FORMAT ".",
left_to_commit / BytesPerWord, left_until_max / BytesPerWord, left_until_GC / BytesPerWord);
return left_to_commit / BytesPerWord;
}
void MetaspaceGC::compute_new_size() {
assert(_shrink_factor <= 100, "invalid shrink factor");
uint current_shrink_factor = _shrink_factor;
_shrink_factor = 0;
// Using committed_bytes() for used_after_gc is an overestimation, since the
// chunk free lists are included in committed_bytes() and the memory in an
// un-fragmented chunk free list is available for future allocations.
// However, if the chunk free lists becomes fragmented, then the memory may
// not be available for future allocations and the memory is therefore "in use".
// Including the chunk free lists in the definition of "in use" is therefore
// necessary. Not including the chunk free lists can cause capacity_until_GC to
// shrink below committed_bytes() and this has caused serious bugs in the past.
const size_t used_after_gc = MetaspaceUtils::committed_bytes();
const size_t capacity_until_GC = MetaspaceGC::capacity_until_GC();
const double minimum_free_percentage = MinMetaspaceFreeRatio / 100.0;
const double maximum_used_percentage = 1.0 - minimum_free_percentage;
const double min_tmp = used_after_gc / maximum_used_percentage;
size_t minimum_desired_capacity =
(size_t)MIN2(min_tmp, double(max_uintx));
// Don't shrink less than the initial generation size
minimum_desired_capacity = MAX2(minimum_desired_capacity,
MetaspaceSize);
log_trace(gc, metaspace)("MetaspaceGC::compute_new_size: ");
log_trace(gc, metaspace)(" minimum_free_percentage: %6.2f maximum_used_percentage: %6.2f",
minimum_free_percentage, maximum_used_percentage);
log_trace(gc, metaspace)(" used_after_gc : %6.1fKB", used_after_gc / (double) K);
size_t shrink_bytes = 0;
if (capacity_until_GC < minimum_desired_capacity) {
// If we have less capacity below the metaspace HWM, then
// increment the HWM.
size_t expand_bytes = minimum_desired_capacity - capacity_until_GC;
expand_bytes = align_up(expand_bytes, Metaspace::commit_alignment());
// Don't expand unless it's significant
if (expand_bytes >= MinMetaspaceExpansion) {
size_t new_capacity_until_GC = 0;
bool succeeded = MetaspaceGC::inc_capacity_until_GC(expand_bytes, &new_capacity_until_GC);
assert(succeeded, "Should always succesfully increment HWM when at safepoint");
Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
new_capacity_until_GC,
MetaspaceGCThresholdUpdater::ComputeNewSize);
log_trace(gc, metaspace)(" expanding: minimum_desired_capacity: %6.1fKB expand_bytes: %6.1fKB MinMetaspaceExpansion: %6.1fKB new metaspace HWM: %6.1fKB",
minimum_desired_capacity / (double) K,
expand_bytes / (double) K,
MinMetaspaceExpansion / (double) K,
new_capacity_until_GC / (double) K);
}
return;
}
// No expansion, now see if we want to shrink
// We would never want to shrink more than this
assert(capacity_until_GC >= minimum_desired_capacity,
SIZE_FORMAT " >= " SIZE_FORMAT,
capacity_until_GC, minimum_desired_capacity);
size_t max_shrink_bytes = capacity_until_GC - minimum_desired_capacity;
// Should shrinking be considered?
if (MaxMetaspaceFreeRatio < 100) {
const double maximum_free_percentage = MaxMetaspaceFreeRatio / 100.0;
const double minimum_used_percentage = 1.0 - maximum_free_percentage;
const double max_tmp = used_after_gc / minimum_used_percentage;
size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx));
maximum_desired_capacity = MAX2(maximum_desired_capacity,
MetaspaceSize);
log_trace(gc, metaspace)(" maximum_free_percentage: %6.2f minimum_used_percentage: %6.2f",
maximum_free_percentage, minimum_used_percentage);
log_trace(gc, metaspace)(" minimum_desired_capacity: %6.1fKB maximum_desired_capacity: %6.1fKB",
minimum_desired_capacity / (double) K, maximum_desired_capacity / (double) K);
assert(minimum_desired_capacity <= maximum_desired_capacity,
"sanity check");
if (capacity_until_GC > maximum_desired_capacity) {
// Capacity too large, compute shrinking size
shrink_bytes = capacity_until_GC - maximum_desired_capacity;
// We don't want shrink all the way back to initSize if people call
// System.gc(), because some programs do that between "phases" and then
// we'd just have to grow the heap up again for the next phase. So we
// damp the shrinking: 0% on the first call, 10% on the second call, 40%
// on the third call, and 100% by the fourth call. But if we recompute
// size without shrinking, it goes back to 0%.
shrink_bytes = shrink_bytes / 100 * current_shrink_factor;
shrink_bytes = align_down(shrink_bytes, Metaspace::commit_alignment());
assert(shrink_bytes <= max_shrink_bytes,
"invalid shrink size " SIZE_FORMAT " not <= " SIZE_FORMAT,
shrink_bytes, max_shrink_bytes);
if (current_shrink_factor == 0) {
_shrink_factor = 10;
} else {
_shrink_factor = MIN2(current_shrink_factor * 4, (uint) 100);
}
log_trace(gc, metaspace)(" shrinking: initThreshold: %.1fK maximum_desired_capacity: %.1fK",
MetaspaceSize / (double) K, maximum_desired_capacity / (double) K);
log_trace(gc, metaspace)(" shrink_bytes: %.1fK current_shrink_factor: %d new shrink factor: %d MinMetaspaceExpansion: %.1fK",
shrink_bytes / (double) K, current_shrink_factor, _shrink_factor, MinMetaspaceExpansion / (double) K);
}
}
// Don't shrink unless it's significant
if (shrink_bytes >= MinMetaspaceExpansion &&
((capacity_until_GC - shrink_bytes) >= MetaspaceSize)) {
size_t new_capacity_until_GC = MetaspaceGC::dec_capacity_until_GC(shrink_bytes);
Metaspace::tracer()->report_gc_threshold(capacity_until_GC,
new_capacity_until_GC,
MetaspaceGCThresholdUpdater::ComputeNewSize);
}
}
// Metadebug methods
void Metadebug::init_allocation_fail_alot_count() {
if (MetadataAllocationFailALot) {
_allocation_fail_alot_count =
1+(long)((double)MetadataAllocationFailALotInterval*os::random()/(max_jint+1.0));
}
}
#ifdef ASSERT
bool Metadebug::test_metadata_failure() {
if (MetadataAllocationFailALot &&
Threads::is_vm_complete()) {
if (_allocation_fail_alot_count > 0) {
_allocation_fail_alot_count--;
} else {
log_trace(gc, metaspace, freelist)("Metadata allocation failing for MetadataAllocationFailALot");
init_allocation_fail_alot_count();
return true;
}
}
return false;
}
#endif
// ChunkManager methods
size_t ChunkManager::free_chunks_total_words() {
return _free_chunks_total;
}
size_t ChunkManager::free_chunks_total_bytes() {
return free_chunks_total_words() * BytesPerWord;
}
// Update internal accounting after a chunk was added
void ChunkManager::account_for_added_chunk(const Metachunk* c) {
assert_lock_strong(MetaspaceExpand_lock);
_free_chunks_count ++;
_free_chunks_total += c->word_size();
}
// Update internal accounting after a chunk was removed
void ChunkManager::account_for_removed_chunk(const Metachunk* c) {
assert_lock_strong(MetaspaceExpand_lock);
assert(_free_chunks_count >= 1,
"ChunkManager::_free_chunks_count: about to go negative (" SIZE_FORMAT ").", _free_chunks_count);
assert(_free_chunks_total >= c->word_size(),
"ChunkManager::_free_chunks_total: about to go negative"
"(now: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ").", _free_chunks_total, c->word_size());
_free_chunks_count --;
_free_chunks_total -= c->word_size();
}
size_t ChunkManager::free_chunks_count() {
#ifdef ASSERT
if (!UseConcMarkSweepGC && !MetaspaceExpand_lock->is_locked()) {
MutexLockerEx cl(MetaspaceExpand_lock,
Mutex::_no_safepoint_check_flag);
// This lock is only needed in debug because the verification
// of the _free_chunks_totals walks the list of free chunks
slow_locked_verify_free_chunks_count();
}
#endif
return _free_chunks_count;
}
ChunkIndex ChunkManager::list_index(size_t size) {
return get_chunk_type_by_size(size, is_class());
}
size_t ChunkManager::size_by_index(ChunkIndex index) const {
index_bounds_check(index);
assert(index != HumongousIndex, "Do not call for humongous chunks.");
return get_size_for_nonhumongous_chunktype(index, is_class());
}
void ChunkManager::locked_verify_free_chunks_total() {
assert_lock_strong(MetaspaceExpand_lock);
assert(sum_free_chunks() == _free_chunks_total,
"_free_chunks_total " SIZE_FORMAT " is not the"
" same as sum " SIZE_FORMAT, _free_chunks_total,
sum_free_chunks());
}
void ChunkManager::locked_verify_free_chunks_count() {
assert_lock_strong(MetaspaceExpand_lock);
assert(sum_free_chunks_count() == _free_chunks_count,
"_free_chunks_count " SIZE_FORMAT " is not the"
" same as sum " SIZE_FORMAT, _free_chunks_count,
sum_free_chunks_count());
}
void ChunkManager::verify() {
MutexLockerEx cl(MetaspaceExpand_lock,
Mutex::_no_safepoint_check_flag);
locked_verify();
}
void ChunkManager::locked_verify() {
locked_verify_free_chunks_count();
locked_verify_free_chunks_total();
for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
ChunkList* list = free_chunks(i);
if (list != NULL) {
Metachunk* chunk = list->head();
while (chunk) {
DEBUG_ONLY(do_verify_chunk(chunk);)
assert(chunk->is_tagged_free(), "Chunk should be tagged as free.");
chunk = chunk->next();
}
}
}
}
void ChunkManager::locked_print_free_chunks(outputStream* st) {
assert_lock_strong(MetaspaceExpand_lock);
st->print_cr("Free chunk total " SIZE_FORMAT " count " SIZE_FORMAT,
_free_chunks_total, _free_chunks_count);
}
void ChunkManager::locked_print_sum_free_chunks(outputStream* st) {
assert_lock_strong(MetaspaceExpand_lock);
st->print_cr("Sum free chunk total " SIZE_FORMAT " count " SIZE_FORMAT,
sum_free_chunks(), sum_free_chunks_count());
}
ChunkList* ChunkManager::free_chunks(ChunkIndex index) {
assert(index == SpecializedIndex || index == SmallIndex || index == MediumIndex,
"Bad index: %d", (int)index);
return &_free_chunks[index];
}
// These methods that sum the free chunk lists are used in printing
// methods that are used in product builds.
size_t ChunkManager::sum_free_chunks() {
assert_lock_strong(MetaspaceExpand_lock);
size_t result = 0;
for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
ChunkList* list = free_chunks(i);
if (list == NULL) {
continue;
}
result = result + list->count() * list->size();
}
result = result + humongous_dictionary()->total_size();
return result;
}
size_t ChunkManager::sum_free_chunks_count() {
assert_lock_strong(MetaspaceExpand_lock);
size_t count = 0;
for (ChunkIndex i = ZeroIndex; i < NumberOfFreeLists; i = next_chunk_index(i)) {
ChunkList* list = free_chunks(i);
if (list == NULL) {
continue;
}
count = count + list->count();
}
count = count + humongous_dictionary()->total_free_blocks();
return count;
}
ChunkList* ChunkManager::find_free_chunks_list(size_t word_size) {
ChunkIndex index = list_index(word_size);
assert(index < HumongousIndex, "No humongous list");
return free_chunks(index);
}
// Helper for chunk splitting: given a target chunk size and a larger free chunk,
// split up the larger chunk into n smaller chunks, at least one of which should be
// the target chunk of target chunk size. The smaller chunks, including the target
// chunk, are returned to the freelist. The pointer to the target chunk is returned.
// Note that this chunk is supposed to be removed from the freelist right away.
Metachunk* ChunkManager::split_chunk(size_t target_chunk_word_size, Metachunk* larger_chunk) {
assert(larger_chunk->word_size() > target_chunk_word_size, "Sanity");
const ChunkIndex larger_chunk_index = larger_chunk->get_chunk_type();
const ChunkIndex target_chunk_index = get_chunk_type_by_size(target_chunk_word_size, is_class());
MetaWord* const region_start = (MetaWord*)larger_chunk;
const size_t region_word_len = larger_chunk->word_size();
MetaWord* const region_end = region_start + region_word_len;
VirtualSpaceNode* const vsn = larger_chunk->container();
OccupancyMap* const ocmap = vsn->occupancy_map();
// Any larger non-humongous chunk size is a multiple of any smaller chunk size.
// Since non-humongous chunks are aligned to their chunk size, the larger chunk should start
// at an address suitable to place the smaller target chunk.
assert_is_aligned(region_start, target_chunk_word_size);
// Remove old chunk.
free_chunks(larger_chunk_index)->remove_chunk(larger_chunk);
larger_chunk->remove_sentinel();
// Prevent access to the old chunk from here on.
larger_chunk = NULL;
// ... and wipe it.
DEBUG_ONLY(memset(region_start, 0xfe, region_word_len * BytesPerWord));
// In its place create first the target chunk...
MetaWord* p = region_start;
Metachunk* target_chunk = ::new (p) Metachunk(target_chunk_index, is_class(), target_chunk_word_size, vsn);
assert(target_chunk == (Metachunk*)p, "Sanity");
target_chunk->set_origin(origin_split);
// Note: we do not need to mark its start in the occupancy map
// because it coincides with the old chunk start.
// Mark chunk as free and return to the freelist.
do_update_in_use_info_for_chunk(target_chunk, false);
free_chunks(target_chunk_index)->return_chunk_at_head(target_chunk);
// This chunk should now be valid and can be verified.
DEBUG_ONLY(do_verify_chunk(target_chunk));
// In the remaining space create the remainder chunks.
p += target_chunk->word_size();
assert(p < region_end, "Sanity");
while (p < region_end) {
// Find the largest chunk size which fits the alignment requirements at address p.
ChunkIndex this_chunk_index = prev_chunk_index(larger_chunk_index);
size_t this_chunk_word_size = 0;
for(;;) {
this_chunk_word_size = get_size_for_nonhumongous_chunktype(this_chunk_index, is_class());
if (is_aligned(p, this_chunk_word_size * BytesPerWord)) {
break;
} else {
this_chunk_index = prev_chunk_index(this_chunk_index);
assert(this_chunk_index >= target_chunk_index, "Sanity");
}
}
assert(this_chunk_word_size >= target_chunk_word_size, "Sanity");
assert(is_aligned(p, this_chunk_word_size * BytesPerWord), "Sanity");
assert(p + this_chunk_word_size <= region_end, "Sanity");
// Create splitting chunk.
Metachunk* this_chunk = ::new (p) Metachunk(this_chunk_index, is_class(), this_chunk_word_size, vsn);
assert(this_chunk == (Metachunk*)p, "Sanity");
this_chunk->set_origin(origin_split);
ocmap->set_chunk_starts_at_address(p, true);
do_update_in_use_info_for_chunk(this_chunk, false);
// This chunk should be valid and can be verified.
DEBUG_ONLY(do_verify_chunk(this_chunk));
// Return this chunk to freelist and correct counter.
free_chunks(this_chunk_index)->return_chunk_at_head(this_chunk);
_free_chunks_count ++;
log_trace(gc, metaspace, freelist)("Created chunk at " PTR_FORMAT ", word size "
SIZE_FORMAT_HEX " (%s), in split region [" PTR_FORMAT "..." PTR_FORMAT ").",
p2i(this_chunk), this_chunk->word_size(), chunk_size_name(this_chunk_index),
p2i(region_start), p2i(region_end));
p += this_chunk_word_size;
}
return target_chunk;
}
Metachunk* ChunkManager::free_chunks_get(size_t word_size) {
assert_lock_strong(MetaspaceExpand_lock);
slow_locked_verify();
Metachunk* chunk = NULL;
bool we_did_split_a_chunk = false;
if (list_index(word_size) != HumongousIndex) {
ChunkList* free_list = find_free_chunks_list(word_size);
assert(free_list != NULL, "Sanity check");
chunk = free_list->head();
if (chunk == NULL) {
// Split large chunks into smaller chunks if there are no smaller chunks, just large chunks.
// This is the counterpart of the coalescing-upon-chunk-return.
ChunkIndex target_chunk_index = get_chunk_type_by_size(word_size, is_class());
// Is there a larger chunk we could split?
Metachunk* larger_chunk = NULL;
ChunkIndex larger_chunk_index = next_chunk_index(target_chunk_index);
while (larger_chunk == NULL && larger_chunk_index < NumberOfFreeLists) {
larger_chunk = free_chunks(larger_chunk_index)->head();
if (larger_chunk == NULL) {
larger_chunk_index = next_chunk_index(larger_chunk_index);
}
}
if (larger_chunk != NULL) {
assert(larger_chunk->word_size() > word_size, "Sanity");
assert(larger_chunk->get_chunk_type() == larger_chunk_index, "Sanity");
// We found a larger chunk. Lets split it up:
// - remove old chunk
// - in its place, create new smaller chunks, with at least one chunk
// being of target size, the others sized as large as possible. This
// is to make sure the resulting chunks are "as coalesced as possible"
// (similar to VirtualSpaceNode::retire()).
// Note: during this operation both ChunkManager and VirtualSpaceNode
// are temporarily invalid, so be careful with asserts.
log_trace(gc, metaspace, freelist)("%s: splitting chunk " PTR_FORMAT
", word size " SIZE_FORMAT_HEX " (%s), to get a chunk of word size " SIZE_FORMAT_HEX " (%s)...",
(is_class() ? "class space" : "metaspace"), p2i(larger_chunk), larger_chunk->word_size(),
chunk_size_name(larger_chunk_index), word_size, chunk_size_name(target_chunk_index));
chunk = split_chunk(word_size, larger_chunk);
// This should have worked.
assert(chunk != NULL, "Sanity");
assert(chunk->word_size() == word_size, "Sanity");
assert(chunk->is_tagged_free(), "Sanity");
we_did_split_a_chunk = true;
}
}
if (chunk == NULL) {
return NULL;
}
// Remove the chunk as the head of the list.
free_list->remove_chunk(chunk);
log_trace(gc, metaspace, freelist)("ChunkManager::free_chunks_get: free_list: " PTR_FORMAT " chunks left: " SSIZE_FORMAT ".",
p2i(free_list), free_list->count());
} else {
chunk = humongous_dictionary()->get_chunk(word_size);
if (chunk == NULL) {
return NULL;
}
log_debug(gc, metaspace, alloc)("Free list allocate humongous chunk size " SIZE_FORMAT " for requested size " SIZE_FORMAT " waste " SIZE_FORMAT,
chunk->word_size(), word_size, chunk->word_size() - word_size);
}
// Chunk has been removed from the chunk manager; update counters.
account_for_removed_chunk(chunk);
do_update_in_use_info_for_chunk(chunk, true);
chunk->container()->inc_container_count();
chunk->inc_use_count();
// Remove it from the links to this freelist
chunk->set_next(NULL);
chunk->set_prev(NULL);
// Run some verifications (some more if we did a chunk split)
#ifdef ASSERT
if (VerifyMetaspace) {
locked_verify();
VirtualSpaceNode* const vsn = chunk->container();
vsn->verify();
if (we_did_split_a_chunk) {
vsn->verify_free_chunks_are_ideally_merged();
}
}
#endif
return chunk;
}
Metachunk* ChunkManager::chunk_freelist_allocate(size_t word_size) {
assert_lock_strong(MetaspaceExpand_lock);
slow_locked_verify();
// Take from the beginning of the list
Metachunk* chunk = free_chunks_get(word_size);
if (chunk == NULL) {
return NULL;
}
assert((word_size <= chunk->word_size()) ||
(list_index(chunk->word_size()) == HumongousIndex),
"Non-humongous variable sized chunk");
LogTarget(Debug, gc, metaspace, freelist) lt;
if (lt.is_enabled()) {
size_t list_count;
if (list_index(word_size) < HumongousIndex) {
ChunkList* list = find_free_chunks_list(word_size);
list_count = list->count();
} else {
list_count = humongous_dictionary()->total_count();
}
LogStream ls(lt);
ls.print("ChunkManager::chunk_freelist_allocate: " PTR_FORMAT " chunk " PTR_FORMAT " size " SIZE_FORMAT " count " SIZE_FORMAT " ",
p2i(this), p2i(chunk), chunk->word_size(), list_count);
ResourceMark rm;
locked_print_free_chunks(&ls);
}
return chunk;
}
void ChunkManager::return_single_chunk(Metachunk* chunk) {
const ChunkIndex index = chunk->get_chunk_type();
assert_lock_strong(MetaspaceExpand_lock);
DEBUG_ONLY(do_verify_chunk(chunk);)
assert(chunk != NULL, "Expected chunk.");
assert(chunk->container() != NULL, "Container should have been set.");
assert(chunk->is_tagged_free() == false, "Chunk should be in use.");
index_bounds_check(index);
// Note: mangle *before* returning the chunk to the freelist or dictionary. It does not
// matter for the freelist (non-humongous chunks), but the humongous chunk dictionary
// keeps tree node pointers in the chunk payload area which mangle will overwrite.
DEBUG_ONLY(chunk->mangle(badMetaWordVal);)
if (index != HumongousIndex) {
// Return non-humongous chunk to freelist.
ChunkList* list = free_chunks(index);
assert(list->size() == chunk->word_size(), "Wrong chunk type.");
list->return_chunk_at_head(chunk);
log_trace(gc, metaspace, freelist)("returned one %s chunk at " PTR_FORMAT " to freelist.",
chunk_size_name(index), p2i(chunk));
} else {
// Return humongous chunk to dictionary.
assert(chunk->word_size() > free_chunks(MediumIndex)->size(), "Wrong chunk type.");
assert(chunk->word_size() % free_chunks(SpecializedIndex)->size() == 0,
"Humongous chunk has wrong alignment.");
_humongous_dictionary.return_chunk(chunk);
log_trace(gc, metaspace, freelist)("returned one %s chunk at " PTR_FORMAT " (word size " SIZE_FORMAT ") to freelist.",
chunk_size_name(index), p2i(chunk), chunk->word_size());
}
chunk->container()->dec_container_count();
do_update_in_use_info_for_chunk(chunk, false);
// Chunk has been added; update counters.
account_for_added_chunk(chunk);
// Attempt coalesce returned chunks with its neighboring chunks:
// if this chunk is small or special, attempt to coalesce to a medium chunk.
if (index == SmallIndex || index == SpecializedIndex) {
if (!attempt_to_coalesce_around_chunk(chunk, MediumIndex)) {
// This did not work. But if this chunk is special, we still may form a small chunk?
if (index == SpecializedIndex) {
if (!attempt_to_coalesce_around_chunk(chunk, SmallIndex)) {
// give up.
}
}
}
}
}
void ChunkManager::return_chunk_list(Metachunk* chunks) {
if (chunks == NULL) {
return;
}
LogTarget(Trace, gc, metaspace, freelist) log;
if (log.is_enabled()) { // tracing
log.print("returning list of chunks...");
}
unsigned num_chunks_returned = 0;
size_t size_chunks_returned = 0;
Metachunk* cur = chunks;
while (cur != NULL) {
// Capture the next link before it is changed
// by the call to return_chunk_at_head();
Metachunk* next = cur->next();
if (log.is_enabled()) { // tracing
num_chunks_returned ++;
size_chunks_returned += cur->word_size();
}
return_single_chunk(cur);
cur = next;
}
if (log.is_enabled()) { // tracing
log.print("returned %u chunks to freelist, total word size " SIZE_FORMAT ".",
num_chunks_returned, size_chunks_returned);
}
}
void ChunkManager::collect_statistics(ChunkManagerStatistics* out) const {
MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
for (ChunkIndex i = ZeroIndex; i < NumberOfInUseLists; i = next_chunk_index(i)) {
out->chunk_stats(i).add(num_free_chunks(i), size_free_chunks_in_bytes(i) / sizeof(MetaWord));
}
}
// SpaceManager methods
size_t SpaceManager::adjust_initial_chunk_size(size_t requested, bool is_class_space) {
size_t chunk_sizes[] = {
specialized_chunk_size(is_class_space),
small_chunk_size(is_class_space),
medium_chunk_size(is_class_space)
};
// Adjust up to one of the fixed chunk sizes ...
for (size_t i = 0; i < ARRAY_SIZE(chunk_sizes); i++) {
if (requested <= chunk_sizes[i]) {
return chunk_sizes[i];
}
}
// ... or return the size as a humongous chunk.
return requested;
}
size_t SpaceManager::adjust_initial_chunk_size(size_t requested) const {
return adjust_initial_chunk_size(requested, is_class());
}
size_t SpaceManager::get_initial_chunk_size(Metaspace::MetaspaceType type) const {
size_t requested;
if (is_class()) {
switch (type) {
case Metaspace::BootMetaspaceType: requested = Metaspace::first_class_chunk_word_size(); break;
case Metaspace::AnonymousMetaspaceType: requested = ClassSpecializedChunk; break;
case Metaspace::ReflectionMetaspaceType: requested = ClassSpecializedChunk; break;
default: requested = ClassSmallChunk; break;
}
} else {
switch (type) {
case Metaspace::BootMetaspaceType: requested = Metaspace::first_chunk_word_size(); break;
case Metaspace::AnonymousMetaspaceType: requested = SpecializedChunk; break;
case Metaspace::ReflectionMetaspaceType: requested = SpecializedChunk; break;
default: requested = SmallChunk; break;
}
}
// Adjust to one of the fixed chunk sizes (unless humongous)
const size_t adjusted = adjust_initial_chunk_size(requested);
assert(adjusted != 0, "Incorrect initial chunk size. Requested: "
SIZE_FORMAT " adjusted: " SIZE_FORMAT, requested, adjusted);
return adjusted;
}
void SpaceManager::locked_print_chunks_in_use_on(outputStream* st) const {
for (ChunkIndex i = ZeroIndex; i < NumberOfInUseLists; i = next_chunk_index(i)) {
st->print("SpaceManager: " UINTX_FORMAT " %s chunks.",
num_chunks_by_type(i), chunk_size_name(i));
}
chunk_manager()->locked_print_free_chunks(st);
}
size_t SpaceManager::calc_chunk_size(size_t word_size) {
// Decide between a small chunk and a medium chunk. Up to
// _small_chunk_limit small chunks can be allocated.
// After that a medium chunk is preferred.
size_t chunk_word_size;
// Special case for anonymous metadata space.
// Anonymous metadata space is usually small, with majority within 1K - 2K range and
// rarely about 4K (64-bits JVM).
// Instead of jumping to SmallChunk after initial chunk exhausted, keeping allocation
// from SpecializeChunk up to _anon_or_delegating_metadata_specialize_chunk_limit (4)
// reduces space waste from 60+% to around 30%.
if ((_space_type == Metaspace::AnonymousMetaspaceType || _space_type == Metaspace::ReflectionMetaspaceType) &&
_mdtype == Metaspace::NonClassType &&
num_chunks_by_type(SpecializedIndex) < _anon_and_delegating_metadata_specialize_chunk_limit &&
word_size + Metachunk::overhead() <= SpecializedChunk) {
return SpecializedChunk;
}
if (num_chunks_by_type(MediumIndex) == 0 &&
num_chunks_by_type(SmallIndex) < _small_chunk_limit) {
chunk_word_size = (size_t) small_chunk_size();
if (word_size + Metachunk::overhead() > small_chunk_size()) {
chunk_word_size = medium_chunk_size();
}
} else {
chunk_word_size = medium_chunk_size();
}
// Might still need a humongous chunk. Enforce
// humongous allocations sizes to be aligned up to
// the smallest chunk size.
size_t if_humongous_sized_chunk =
align_up(word_size + Metachunk::overhead(),
smallest_chunk_size());
chunk_word_size =
MAX2((size_t) chunk_word_size, if_humongous_sized_chunk);
assert(!SpaceManager::is_humongous(word_size) ||
chunk_word_size == if_humongous_sized_chunk,
"Size calculation is wrong, word_size " SIZE_FORMAT
" chunk_word_size " SIZE_FORMAT,
word_size, chunk_word_size);
Log(gc, metaspace, alloc) log;
if (log.is_debug() && SpaceManager::is_humongous(word_size)) {
log.debug("Metadata humongous allocation:");
log.debug(" word_size " PTR_FORMAT, word_size);
log.debug(" chunk_word_size " PTR_FORMAT, chunk_word_size);
log.debug(" chunk overhead " PTR_FORMAT, Metachunk::overhead());
}
return chunk_word_size;
}
void SpaceManager::track_metaspace_memory_usage() {
if (is_init_completed()) {
if (is_class()) {
MemoryService::track_compressed_class_memory_usage();
}
MemoryService::track_metaspace_memory_usage();
}
}
MetaWord* SpaceManager::grow_and_allocate(size_t word_size) {
assert_lock_strong(_lock);
assert(vs_list()->current_virtual_space() != NULL,
"Should have been set");
assert(current_chunk() == NULL ||
current_chunk()->allocate(word_size) == NULL,
"Don't need to expand");
MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
if (log_is_enabled(Trace, gc, metaspace, freelist)) {
size_t words_left = 0;
size_t words_used = 0;
if (current_chunk() != NULL) {
words_left = current_chunk()->free_word_size();
words_used = current_chunk()->used_word_size();
}
log_trace(gc, metaspace, freelist)("SpaceManager::grow_and_allocate for " SIZE_FORMAT " words " SIZE_FORMAT " words used " SIZE_FORMAT " words left",
word_size, words_used, words_left);
}
// Get another chunk
size_t chunk_word_size = calc_chunk_size(word_size);
Metachunk* next = get_new_chunk(chunk_word_size);
MetaWord* mem = NULL;
// If a chunk was available, add it to the in-use chunk list
// and do an allocation from it.
if (next != NULL) {
// Add to this manager's list of chunks in use.
// If the new chunk is humongous, it was created to serve a single large allocation. In that
// case it usually makes no sense to make it the current chunk, since the next allocation would
// need to allocate a new chunk anyway, while we would now prematurely retire a perfectly
// good chunk which could be used for more normal allocations.
bool make_current = true;
if (next->get_chunk_type() == HumongousIndex &&
current_chunk() != NULL) {
make_current = false;
}
add_chunk(next, make_current);
mem = next->allocate(word_size);
}
// Track metaspace memory usage statistic.
track_metaspace_memory_usage();
return mem;
}
void SpaceManager::print_on(outputStream* st) const {
SpaceManagerStatistics stat;
add_to_statistics(&stat); // will lock _lock.
stat.print_on(st, 1*K, false);
}
SpaceManager::SpaceManager(Metaspace::MetadataType mdtype,
Metaspace::MetaspaceType space_type,
Mutex* lock) :
_mdtype(mdtype),
_space_type(space_type),
_capacity_words(0),
_used_words(0),
_overhead_words(0),
_block_freelists(NULL),
_lock(lock),
_chunk_list(NULL),
_current_chunk(NULL)
{
Metadebug::init_allocation_fail_alot_count();
memset(_num_chunks_by_type, 0, sizeof(_num_chunks_by_type));
log_trace(gc, metaspace, freelist)("SpaceManager(): " PTR_FORMAT, p2i(this));
}
void SpaceManager::account_for_new_chunk(const Metachunk* new_chunk) {
assert_lock_strong(MetaspaceExpand_lock);
_capacity_words += new_chunk->word_size();
_overhead_words += Metachunk::overhead();
DEBUG_ONLY(new_chunk->verify());
_num_chunks_by_type[new_chunk->get_chunk_type()] ++;
// Adjust global counters:
MetaspaceUtils::inc_capacity(mdtype(), new_chunk->word_size());
MetaspaceUtils::inc_overhead(mdtype(), Metachunk::overhead());
}
void SpaceManager::account_for_allocation(size_t words) {
// Note: we should be locked with the ClassloaderData-specific metaspace lock.
// We may or may not be locked with the global metaspace expansion lock.
assert_lock_strong(lock());
// Add to the per SpaceManager totals. This can be done non-atomically.
_used_words += words;
// Adjust global counters. This will be done atomically.
MetaspaceUtils::inc_used(mdtype(), words);
}
void SpaceManager::account_for_spacemanager_death() {
assert_lock_strong(MetaspaceExpand_lock);
MetaspaceUtils::dec_capacity(mdtype(), _capacity_words);
MetaspaceUtils::dec_overhead(mdtype(), _overhead_words);
MetaspaceUtils::dec_used(mdtype(), _used_words);
}
SpaceManager::~SpaceManager() {
// This call this->_lock which can't be done while holding MetaspaceExpand_lock
DEBUG_ONLY(verify_metrics());
MutexLockerEx fcl(MetaspaceExpand_lock,
Mutex::_no_safepoint_check_flag);
chunk_manager()->slow_locked_verify();
account_for_spacemanager_death();
Log(gc, metaspace, freelist) log;
if (log.is_trace()) {
log.trace("~SpaceManager(): " PTR_FORMAT, p2i(this));
ResourceMark rm;
LogStream ls(log.trace());
locked_print_chunks_in_use_on(&ls);
if (block_freelists() != NULL) {
block_freelists()->print_on(&ls);
}
}
// Add all the chunks in use by this space manager
// to the global list of free chunks.
// Follow each list of chunks-in-use and add them to the
// free lists. Each list is NULL terminated.
chunk_manager()->return_chunk_list(chunk_list());
#ifdef ASSERT
_chunk_list = NULL;
_current_chunk = NULL;
#endif
chunk_manager()->slow_locked_verify();
if (_block_freelists != NULL) {
delete _block_freelists;
}
}
void SpaceManager::deallocate(MetaWord* p, size_t word_size) {
assert_lock_strong(lock());
// Allocations and deallocations are in raw_word_size
size_t raw_word_size = get_allocation_word_size(word_size);
// Lazily create a block_freelist
if (block_freelists() == NULL) {
_block_freelists = new BlockFreelist();
}
block_freelists()->return_block(p, raw_word_size);
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_deallocs));
}
// Adds a chunk to the list of chunks in use.
void SpaceManager::add_chunk(Metachunk* new_chunk, bool make_current) {
assert_lock_strong(_lock);
assert(new_chunk != NULL, "Should not be NULL");
assert(new_chunk->next() == NULL, "Should not be on a list");
new_chunk->reset_empty();
// Find the correct list and and set the current
// chunk for that list.
ChunkIndex index = chunk_manager()->list_index(new_chunk->word_size());
if (make_current) {
// If we are to make the chunk current, retire the old current chunk and replace
// it with the new chunk.
retire_current_chunk();
set_current_chunk(new_chunk);
}
// Add the new chunk at the head of its respective chunk list.
new_chunk->set_next(_chunk_list);
_chunk_list = new_chunk;
// Adjust counters.
account_for_new_chunk(new_chunk);
assert(new_chunk->is_empty(), "Not ready for reuse");
Log(gc, metaspace, freelist) log;
if (log.is_trace()) {
log.trace("SpaceManager::added chunk: ");
ResourceMark rm;
LogStream ls(log.trace());
new_chunk->print_on(&ls);
chunk_manager()->locked_print_free_chunks(&ls);
}
}
void SpaceManager::retire_current_chunk() {
if (current_chunk() != NULL) {
size_t remaining_words = current_chunk()->free_word_size();
if (remaining_words >= SmallBlocks::small_block_min_size()) {
MetaWord* ptr = current_chunk()->allocate(remaining_words);
deallocate(ptr, remaining_words);
account_for_allocation(remaining_words);
}
}
}
Metachunk* SpaceManager::get_new_chunk(size_t chunk_word_size) {
// Get a chunk from the chunk freelist
Metachunk* next = chunk_manager()->chunk_freelist_allocate(chunk_word_size);
if (next == NULL) {
next = vs_list()->get_new_chunk(chunk_word_size,
medium_chunk_bunch());
}
Log(gc, metaspace, alloc) log;
if (log.is_debug() && next != NULL &&
SpaceManager::is_humongous(next->word_size())) {
log.debug(" new humongous chunk word size " PTR_FORMAT, next->word_size());
}
return next;
}
MetaWord* SpaceManager::allocate(size_t word_size) {
MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
size_t raw_word_size = get_allocation_word_size(word_size);
BlockFreelist* fl = block_freelists();
MetaWord* p = NULL;
DEBUG_ONLY(if (VerifyMetaspace) verify_metrics_locked());
// Allocation from the dictionary is expensive in the sense that
// the dictionary has to be searched for a size. Don't allocate
// from the dictionary until it starts to get fat. Is this
// a reasonable policy? Maybe an skinny dictionary is fast enough
// for allocations. Do some profiling. JJJ
if (fl != NULL && fl->total_size() > allocation_from_dictionary_limit) {
p = fl->get_block(raw_word_size);
if (p != NULL) {
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_allocs_from_deallocated_blocks));
}
}
if (p == NULL) {
p = allocate_work(raw_word_size);
}
return p;
}
// Returns the address of spaced allocated for "word_size".
// This methods does not know about blocks (Metablocks)
MetaWord* SpaceManager::allocate_work(size_t word_size) {
assert_lock_strong(lock());
#ifdef ASSERT
if (Metadebug::test_metadata_failure()) {
return NULL;
}
#endif
// Is there space in the current chunk?
MetaWord* result = NULL;
if (current_chunk() != NULL) {
result = current_chunk()->allocate(word_size);
}
if (result == NULL) {
result = grow_and_allocate(word_size);
}
if (result != NULL) {
account_for_allocation(word_size);
}
return result;
}
void SpaceManager::verify() {
Metachunk* curr = chunk_list();
while (curr != NULL) {
DEBUG_ONLY(do_verify_chunk(curr);)
assert(curr->is_tagged_free() == false, "Chunk should be tagged as in use.");
curr = curr->next();
}
}
void SpaceManager::verify_chunk_size(Metachunk* chunk) {
assert(is_humongous(chunk->word_size()) ||
chunk->word_size() == medium_chunk_size() ||
chunk->word_size() == small_chunk_size() ||
chunk->word_size() == specialized_chunk_size(),
"Chunk size is wrong");
return;
}
void SpaceManager::add_to_statistics_locked(SpaceManagerStatistics* out) const {
assert_lock_strong(lock());
Metachunk* chunk = chunk_list();
while (chunk != NULL) {
UsedChunksStatistics& chunk_stat = out->chunk_stats(chunk->get_chunk_type());
chunk_stat.add_num(1);
chunk_stat.add_cap(chunk->word_size());
chunk_stat.add_overhead(Metachunk::overhead());
chunk_stat.add_used(chunk->used_word_size() - Metachunk::overhead());
if (chunk != current_chunk()) {
chunk_stat.add_waste(chunk->free_word_size());
} else {
chunk_stat.add_free(chunk->free_word_size());
}
chunk = chunk->next();
}
if (block_freelists() != NULL) {
out->add_free_blocks_info(block_freelists()->num_blocks(), block_freelists()->total_size());
}
}
void SpaceManager::add_to_statistics(SpaceManagerStatistics* out) const {
MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
add_to_statistics_locked(out);
}
#ifdef ASSERT
void SpaceManager::verify_metrics_locked() const {
assert_lock_strong(lock());
SpaceManagerStatistics stat;
add_to_statistics_locked(&stat);
UsedChunksStatistics chunk_stats = stat.totals();
DEBUG_ONLY(chunk_stats.check_sanity());
assert_counter(_capacity_words, chunk_stats.cap(), "SpaceManager::_capacity_words");
assert_counter(_used_words, chunk_stats.used(), "SpaceManager::_used_words");
assert_counter(_overhead_words, chunk_stats.overhead(), "SpaceManager::_overhead_words");
}
void SpaceManager::verify_metrics() const {
MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
verify_metrics_locked();
}
#endif // ASSERT
// MetaspaceUtils
size_t MetaspaceUtils::_capacity_words [Metaspace:: MetadataTypeCount] = {0, 0};
size_t MetaspaceUtils::_overhead_words [Metaspace:: MetadataTypeCount] = {0, 0};
volatile size_t MetaspaceUtils::_used_words [Metaspace:: MetadataTypeCount] = {0, 0};
// Collect used metaspace statistics. This involves walking the CLDG. The resulting
// output will be the accumulated values for all live metaspaces.
// Note: method does not do any locking.
void MetaspaceUtils::collect_statistics(ClassLoaderMetaspaceStatistics* out) {
out->reset();
ClassLoaderDataGraphMetaspaceIterator iter;
while (iter.repeat()) {
ClassLoaderMetaspace* msp = iter.get_next();
if (msp != NULL) {
msp->add_to_statistics(out);
}
}
}
size_t MetaspaceUtils::free_in_vs_bytes(Metaspace::MetadataType mdtype) {
VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
return list == NULL ? 0 : list->free_bytes();
}
size_t MetaspaceUtils::free_in_vs_bytes() {
return free_in_vs_bytes(Metaspace::ClassType) + free_in_vs_bytes(Metaspace::NonClassType);
}
static void inc_stat_nonatomically(size_t* pstat, size_t words) {
assert_lock_strong(MetaspaceExpand_lock);
(*pstat) += words;
}
static void dec_stat_nonatomically(size_t* pstat, size_t words) {
assert_lock_strong(MetaspaceExpand_lock);
const size_t size_now = *pstat;
assert(size_now >= words, "About to decrement counter below zero "
"(current value: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ".",
size_now, words);
*pstat = size_now - words;
}
static void inc_stat_atomically(volatile size_t* pstat, size_t words) {
Atomic::add(words, pstat);
}
static void dec_stat_atomically(volatile size_t* pstat, size_t words) {
const size_t size_now = *pstat;
assert(size_now >= words, "About to decrement counter below zero "
"(current value: " SIZE_FORMAT ", decrement value: " SIZE_FORMAT ".",
size_now, words);
Atomic::sub(words, pstat);
}
void MetaspaceUtils::dec_capacity(Metaspace::MetadataType mdtype, size_t words) {
dec_stat_nonatomically(&_capacity_words[mdtype], words);
}
void MetaspaceUtils::inc_capacity(Metaspace::MetadataType mdtype, size_t words) {
inc_stat_nonatomically(&_capacity_words[mdtype], words);
}
void MetaspaceUtils::dec_used(Metaspace::MetadataType mdtype, size_t words) {
dec_stat_atomically(&_used_words[mdtype], words);
}
void MetaspaceUtils::inc_used(Metaspace::MetadataType mdtype, size_t words) {
inc_stat_atomically(&_used_words[mdtype], words);
}
void MetaspaceUtils::dec_overhead(Metaspace::MetadataType mdtype, size_t words) {
dec_stat_nonatomically(&_overhead_words[mdtype], words);
}
void MetaspaceUtils::inc_overhead(Metaspace::MetadataType mdtype, size_t words) {
inc_stat_nonatomically(&_overhead_words[mdtype], words);
}
size_t MetaspaceUtils::reserved_bytes(Metaspace::MetadataType mdtype) {
VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
return list == NULL ? 0 : list->reserved_bytes();
}
size_t MetaspaceUtils::committed_bytes(Metaspace::MetadataType mdtype) {
VirtualSpaceList* list = Metaspace::get_space_list(mdtype);
return list == NULL ? 0 : list->committed_bytes();
}
size_t MetaspaceUtils::min_chunk_size_words() { return Metaspace::first_chunk_word_size(); }
size_t MetaspaceUtils::free_chunks_total_words(Metaspace::MetadataType mdtype) {
ChunkManager* chunk_manager = Metaspace::get_chunk_manager(mdtype);
if (chunk_manager == NULL) {
return 0;
}
chunk_manager->slow_verify();
return chunk_manager->free_chunks_total_words();
}
size_t MetaspaceUtils::free_chunks_total_bytes(Metaspace::MetadataType mdtype) {
return free_chunks_total_words(mdtype) * BytesPerWord;
}
size_t MetaspaceUtils::free_chunks_total_words() {
return free_chunks_total_words(Metaspace::ClassType) +
free_chunks_total_words(Metaspace::NonClassType);
}
size_t MetaspaceUtils::free_chunks_total_bytes() {
return free_chunks_total_words() * BytesPerWord;
}
bool MetaspaceUtils::has_chunk_free_list(Metaspace::MetadataType mdtype) {
return Metaspace::get_chunk_manager(mdtype) != NULL;
}
MetaspaceChunkFreeListSummary MetaspaceUtils::chunk_free_list_summary(Metaspace::MetadataType mdtype) {
if (!has_chunk_free_list(mdtype)) {
return MetaspaceChunkFreeListSummary();
}
const ChunkManager* cm = Metaspace::get_chunk_manager(mdtype);
return cm->chunk_free_list_summary();
}
void MetaspaceUtils::print_metaspace_change(size_t prev_metadata_used) {
log_info(gc, metaspace)("Metaspace: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)",
prev_metadata_used/K, used_bytes()/K, reserved_bytes()/K);
}
void MetaspaceUtils::print_on(outputStream* out) {
Metaspace::MetadataType nct = Metaspace::NonClassType;
out->print_cr(" Metaspace "
"used " SIZE_FORMAT "K, "
"capacity " SIZE_FORMAT "K, "
"committed " SIZE_FORMAT "K, "
"reserved " SIZE_FORMAT "K",
used_bytes()/K,
capacity_bytes()/K,
committed_bytes()/K,
reserved_bytes()/K);
if (Metaspace::using_class_space()) {
Metaspace::MetadataType ct = Metaspace::ClassType;
out->print_cr(" class space "
"used " SIZE_FORMAT "K, "
"capacity " SIZE_FORMAT "K, "
"committed " SIZE_FORMAT "K, "
"reserved " SIZE_FORMAT "K",
used_bytes(ct)/K,
capacity_bytes(ct)/K,
committed_bytes(ct)/K,
reserved_bytes(ct)/K);
}
}
class PrintCLDMetaspaceInfoClosure : public CLDClosure {
private:
outputStream* const _out;
const size_t _scale;
const bool _do_print;
const bool _break_down_by_chunktype;
public:
uintx _num_loaders;
ClassLoaderMetaspaceStatistics _stats_total;
uintx _num_loaders_by_spacetype [Metaspace::MetaspaceTypeCount];
ClassLoaderMetaspaceStatistics _stats_by_spacetype [Metaspace::MetaspaceTypeCount];
public:
PrintCLDMetaspaceInfoClosure(outputStream* out, size_t scale, bool do_print, bool break_down_by_chunktype)
: _out(out), _scale(scale), _do_print(do_print), _break_down_by_chunktype(break_down_by_chunktype)
, _num_loaders(0)
{
memset(_num_loaders_by_spacetype, 0, sizeof(_num_loaders_by_spacetype));
}
void do_cld(ClassLoaderData* cld) {
assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
ClassLoaderMetaspace* msp = cld->metaspace_or_null();
if (msp == NULL) {
return;
}
// Collect statistics for this class loader metaspace
ClassLoaderMetaspaceStatistics this_cld_stat;
msp->add_to_statistics(&this_cld_stat);
// And add it to the running totals
_stats_total.add(this_cld_stat);
_num_loaders ++;
_stats_by_spacetype[msp->space_type()].add(this_cld_stat);
_num_loaders_by_spacetype[msp->space_type()] ++;
// Optionally, print.
if (_do_print) {
_out->print(UINTX_FORMAT_W(4) ": ", _num_loaders);
if (cld->is_anonymous()) {
_out->print("ClassLoaderData " PTR_FORMAT " for anonymous class", p2i(cld));
} else {
ResourceMark rm;
_out->print("ClassLoaderData " PTR_FORMAT " for %s", p2i(cld), cld->loader_name());
}
if (cld->is_unloading()) {
_out->print(" (unloading)");
}
this_cld_stat.print_on(_out, _scale, _break_down_by_chunktype);
_out->cr();
}
} // do_cld
};
void MetaspaceUtils::print_vs(outputStream* out, size_t scale) {
const size_t reserved_nonclass_words = reserved_bytes(Metaspace::NonClassType) / sizeof(MetaWord);
const size_t committed_nonclass_words = committed_bytes(Metaspace::NonClassType) / sizeof(MetaWord);
{
if (Metaspace::using_class_space()) {
out->print(" Non-class space: ");
}
print_scaled_words(out, reserved_nonclass_words, scale, 7);
out->print(" reserved, ");
print_scaled_words_and_percentage(out, committed_nonclass_words, reserved_nonclass_words, scale, 7);
out->print_cr(" committed ");
if (Metaspace::using_class_space()) {
const size_t reserved_class_words = reserved_bytes(Metaspace::ClassType) / sizeof(MetaWord);
const size_t committed_class_words = committed_bytes(Metaspace::ClassType) / sizeof(MetaWord);
out->print(" Class space: ");
print_scaled_words(out, reserved_class_words, scale, 7);
out->print(" reserved, ");
print_scaled_words_and_percentage(out, committed_class_words, reserved_class_words, scale, 7);
out->print_cr(" committed ");
const size_t reserved_words = reserved_nonclass_words + reserved_class_words;
const size_t committed_words = committed_nonclass_words + committed_class_words;
out->print(" Both: ");
print_scaled_words(out, reserved_words, scale, 7);
out->print(" reserved, ");
print_scaled_words_and_percentage(out, committed_words, reserved_words, scale, 7);
out->print_cr(" committed ");
}
}
}
// This will print out a basic metaspace usage report but
// unlike print_report() is guaranteed not to lock or to walk the CLDG.
void MetaspaceUtils::print_basic_report(outputStream* out, size_t scale) {
out->cr();
out->print_cr("Usage:");
if (Metaspace::using_class_space()) {
out->print(" Non-class: ");
}
// In its most basic form, we do not require walking the CLDG. Instead, just print the running totals from
// MetaspaceUtils.
const size_t cap_nc = MetaspaceUtils::capacity_words(Metaspace::NonClassType);
const size_t overhead_nc = MetaspaceUtils::overhead_words(Metaspace::NonClassType);
const size_t used_nc = MetaspaceUtils::used_words(Metaspace::NonClassType);
const size_t free_and_waste_nc = cap_nc - overhead_nc - used_nc;
print_scaled_words(out, cap_nc, scale, 5);
out->print(" capacity, ");
print_scaled_words_and_percentage(out, used_nc, cap_nc, scale, 5);
out->print(" used, ");
print_scaled_words_and_percentage(out, free_and_waste_nc, cap_nc, scale, 5);
out->print(" free+waste, ");
print_scaled_words_and_percentage(out, overhead_nc, cap_nc, scale, 5);
out->print(" overhead. ");
out->cr();
if (Metaspace::using_class_space()) {
const size_t cap_c = MetaspaceUtils::capacity_words(Metaspace::ClassType);
const size_t overhead_c = MetaspaceUtils::overhead_words(Metaspace::ClassType);
const size_t used_c = MetaspaceUtils::used_words(Metaspace::ClassType);
const size_t free_and_waste_c = cap_c - overhead_c - used_c;
out->print(" Class: ");
print_scaled_words(out, cap_c, scale, 5);
out->print(" capacity, ");
print_scaled_words_and_percentage(out, used_c, cap_c, scale, 5);
out->print(" used, ");
print_scaled_words_and_percentage(out, free_and_waste_c, cap_c, scale, 5);
out->print(" free+waste, ");
print_scaled_words_and_percentage(out, overhead_c, cap_c, scale, 5);
out->print(" overhead. ");
out->cr();
out->print(" Both: ");
const size_t cap = cap_nc + cap_c;
print_scaled_words(out, cap, scale, 5);
out->print(" capacity, ");
print_scaled_words_and_percentage(out, used_nc + used_c, cap, scale, 5);
out->print(" used, ");
print_scaled_words_and_percentage(out, free_and_waste_nc + free_and_waste_c, cap, scale, 5);
out->print(" free+waste, ");
print_scaled_words_and_percentage(out, overhead_nc + overhead_c, cap, scale, 5);
out->print(" overhead. ");
out->cr();
}
out->cr();
out->print_cr("Virtual space:");
print_vs(out, scale);
out->cr();
out->print_cr("Chunk freelists:");
if (Metaspace::using_class_space()) {
out->print(" Non-Class: ");
}
print_human_readable_size(out, Metaspace::chunk_manager_metadata()->free_chunks_total_words(), scale);
out->cr();
if (Metaspace::using_class_space()) {
out->print(" Class: ");
print_human_readable_size(out, Metaspace::chunk_manager_class()->free_chunks_total_words(), scale);
out->cr();
out->print(" Both: ");
print_human_readable_size(out, Metaspace::chunk_manager_class()->free_chunks_total_words() +
Metaspace::chunk_manager_metadata()->free_chunks_total_words(), scale);
out->cr();
}
out->cr();
}
void MetaspaceUtils::print_report(outputStream* out, size_t scale, int flags) {
const bool print_loaders = (flags & rf_show_loaders) > 0;
const bool print_by_chunktype = (flags & rf_break_down_by_chunktype) > 0;
const bool print_by_spacetype = (flags & rf_break_down_by_spacetype) > 0;
// Some report options require walking the class loader data graph.
PrintCLDMetaspaceInfoClosure cl(out, scale, print_loaders, print_by_chunktype);
if (print_loaders) {
out->cr();
out->print_cr("Usage per loader:");
out->cr();
}
ClassLoaderDataGraph::cld_do(&cl); // collect data and optionally print
// Print totals, broken up by space type.
if (print_by_spacetype) {
out->cr();
out->print_cr("Usage per space type:");
out->cr();
for (int space_type = (int)Metaspace::ZeroMetaspaceType;
space_type < (int)Metaspace::MetaspaceTypeCount; space_type ++)
{
uintx num = cl._num_loaders_by_spacetype[space_type];
out->print("%s (" UINTX_FORMAT " loader%s)%c",
space_type_name((Metaspace::MetaspaceType)space_type),
num, (num == 1 ? "" : "s"), (num > 0 ? ':' : '.'));
if (num > 0) {
cl._stats_by_spacetype[space_type].print_on(out, scale, print_by_chunktype);
}
out->cr();
}
}
// Print totals for in-use data:
out->cr();
out->print_cr("Total Usage ( " UINTX_FORMAT " loader%s)%c",
cl._num_loaders, (cl._num_loaders == 1 ? "" : "s"), (cl._num_loaders > 0 ? ':' : '.'));
cl._stats_total.print_on(out, scale, print_by_chunktype);
// -- Print Virtual space.
out->cr();
out->print_cr("Virtual space:");
print_vs(out, scale);
// -- Print VirtualSpaceList details.
if ((flags & rf_show_vslist) > 0) {
out->cr();
out->print_cr("Virtual space list%s:", Metaspace::using_class_space() ? "s" : "");
if (Metaspace::using_class_space()) {
out->print_cr(" Non-Class:");
}
Metaspace::space_list()->print_on(out, scale);
if (Metaspace::using_class_space()) {
out->print_cr(" Class:");
Metaspace::class_space_list()->print_on(out, scale);
}
}
out->cr();
// -- Print VirtualSpaceList map.
if ((flags & rf_show_vsmap) > 0) {
out->cr();
out->print_cr("Virtual space map:");
if (Metaspace::using_class_space()) {
out->print_cr(" Non-Class:");
}
Metaspace::space_list()->print_map(out);
if (Metaspace::using_class_space()) {
out->print_cr(" Class:");
Metaspace::class_space_list()->print_map(out);
}
}
out->cr();
// -- Print Freelists (ChunkManager) details
out->cr();
out->print_cr("Chunk freelist%s:", Metaspace::using_class_space() ? "s" : "");
ChunkManagerStatistics non_class_cm_stat;
Metaspace::chunk_manager_metadata()->collect_statistics(&non_class_cm_stat);
if (Metaspace::using_class_space()) {
out->print_cr(" Non-Class:");
}
non_class_cm_stat.print_on(out, scale);
if (Metaspace::using_class_space()) {
ChunkManagerStatistics class_cm_stat;
Metaspace::chunk_manager_class()->collect_statistics(&class_cm_stat);
out->print_cr(" Class:");
class_cm_stat.print_on(out, scale);
}
// As a convenience, print a summary of common waste.
out->cr();
out->print("Waste ");
// For all wastages, print percentages from total. As total use the total size of memory committed for metaspace.
const size_t committed_words = committed_bytes() / BytesPerWord;
out->print("(percentages refer to total committed size ");
print_scaled_words(out, committed_words, scale);
out->print_cr("):");
// Print space committed but not yet used by any class loader
const size_t unused_words_in_vs = MetaspaceUtils::free_in_vs_bytes() / BytesPerWord;
out->print(" Committed unused: ");
print_scaled_words_and_percentage(out, unused_words_in_vs, committed_words, scale, 6);
out->cr();
// Print waste for in-use chunks.
UsedChunksStatistics ucs_nonclass = cl._stats_total.nonclass_sm_stats().totals();
UsedChunksStatistics ucs_class = cl._stats_total.class_sm_stats().totals();
UsedChunksStatistics ucs_all;
ucs_all.add(ucs_nonclass);
ucs_all.add(ucs_class);
out->print(" Waste in chunks in use: ");
print_scaled_words_and_percentage(out, ucs_all.waste(), committed_words, scale, 6);
out->cr();
out->print(" Free in chunks in use: ");
print_scaled_words_and_percentage(out, ucs_all.free(), committed_words, scale, 6);
out->cr();
out->print(" Overhead in chunks in use: ");
print_scaled_words_and_percentage(out, ucs_all.overhead(), committed_words, scale, 6);
out->cr();
// Print waste in free chunks.
const size_t total_capacity_in_free_chunks =
Metaspace::chunk_manager_metadata()->free_chunks_total_words() +
(Metaspace::using_class_space() ? Metaspace::chunk_manager_class()->free_chunks_total_words() : 0);
out->print(" In free chunks: ");
print_scaled_words_and_percentage(out, total_capacity_in_free_chunks, committed_words, scale, 6);
out->cr();
// Print waste in deallocated blocks.
const uintx free_blocks_num =
cl._stats_total.nonclass_sm_stats().free_blocks_num() +
cl._stats_total.class_sm_stats().free_blocks_num();
const size_t free_blocks_cap_words =
cl._stats_total.nonclass_sm_stats().free_blocks_cap_words() +
cl._stats_total.class_sm_stats().free_blocks_cap_words();
out->print("Deallocated from chunks in use: ");
print_scaled_words_and_percentage(out, free_blocks_cap_words, committed_words, scale, 6);
out->print(" (" UINTX_FORMAT " blocks)", free_blocks_num);
out->cr();
// Print total waste.
const size_t total_waste = ucs_all.waste() + ucs_all.free() + ucs_all.overhead() + total_capacity_in_free_chunks
+ free_blocks_cap_words + unused_words_in_vs;
out->print(" -total-: ");
print_scaled_words_and_percentage(out, total_waste, committed_words, scale, 6);
out->cr();
// Print internal statistics
#ifdef ASSERT
out->cr();
out->cr();
out->print_cr("Internal statistics:");
out->cr();
out->print_cr("Number of allocations: " UINTX_FORMAT ".", g_internal_statistics.num_allocs);
out->print_cr("Number of space births: " UINTX_FORMAT ".", g_internal_statistics.num_metaspace_births);
out->print_cr("Number of space deaths: " UINTX_FORMAT ".", g_internal_statistics.num_metaspace_deaths);
out->print_cr("Number of virtual space node births: " UINTX_FORMAT ".", g_internal_statistics.num_vsnodes_created);
out->print_cr("Number of virtual space node deaths: " UINTX_FORMAT ".", g_internal_statistics.num_vsnodes_purged);
out->print_cr("Number of times virtual space nodes were expanded: " UINTX_FORMAT ".", g_internal_statistics.num_committed_space_expanded);
out->print_cr("Number of deallocations: " UINTX_FORMAT " (" UINTX_FORMAT " external).", g_internal_statistics.num_deallocs, g_internal_statistics.num_external_deallocs);
out->print_cr("Allocations from deallocated blocks: " UINTX_FORMAT ".", g_internal_statistics.num_allocs_from_deallocated_blocks);
out->cr();
#endif
// Print some interesting settings
out->cr();
out->cr();
out->print("MaxMetaspaceSize: ");
print_human_readable_size(out, MaxMetaspaceSize, scale);
out->cr();
out->print("InitialBootClassLoaderMetaspaceSize: ");
print_human_readable_size(out, InitialBootClassLoaderMetaspaceSize, scale);
out->cr();
out->print("UseCompressedClassPointers: %s", UseCompressedClassPointers ? "true" : "false");
out->cr();
if (Metaspace::using_class_space()) {
out->print("CompressedClassSpaceSize: ");
print_human_readable_size(out, CompressedClassSpaceSize, scale);
}
out->cr();
out->cr();
} // MetaspaceUtils::print_report()
// Prints an ASCII representation of the given space.
void MetaspaceUtils::print_metaspace_map(outputStream* out, Metaspace::MetadataType mdtype) {
MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
const bool for_class = mdtype == Metaspace::ClassType ? true : false;
VirtualSpaceList* const vsl = for_class ? Metaspace::class_space_list() : Metaspace::space_list();
if (vsl != NULL) {
if (for_class) {
if (!Metaspace::using_class_space()) {
out->print_cr("No Class Space.");
return;
}
out->print_raw("---- Metaspace Map (Class Space) ----");
} else {
out->print_raw("---- Metaspace Map (Non-Class Space) ----");
}
// Print legend:
out->cr();
out->print_cr("Chunk Types (uppercase chunks are in use): x-specialized, s-small, m-medium, h-humongous.");
out->cr();
VirtualSpaceList* const vsl = for_class ? Metaspace::class_space_list() : Metaspace::space_list();
vsl->print_map(out);
out->cr();
}
}
void MetaspaceUtils::verify_free_chunks() {
Metaspace::chunk_manager_metadata()->verify();
if (Metaspace::using_class_space()) {
Metaspace::chunk_manager_class()->verify();
}
}
void MetaspaceUtils::verify_metrics() {
#ifdef ASSERT
// Please note: there are time windows where the internal counters are out of sync with
// reality. For example, when a newly created ClassLoaderMetaspace creates its first chunk -
// the ClassLoaderMetaspace is not yet attached to its ClassLoaderData object and hence will
// not be counted when iterating the CLDG. So be careful when you call this method.
ClassLoaderMetaspaceStatistics total_stat;
collect_statistics(&total_stat);
UsedChunksStatistics nonclass_chunk_stat = total_stat.nonclass_sm_stats().totals();
UsedChunksStatistics class_chunk_stat = total_stat.class_sm_stats().totals();
bool mismatch = false;
for (int i = 0; i < Metaspace::MetadataTypeCount; i ++) {
Metaspace::MetadataType mdtype = (Metaspace::MetadataType)i;
UsedChunksStatistics chunk_stat = total_stat.sm_stats(mdtype).totals();
if (capacity_words(mdtype) != chunk_stat.cap() ||
used_words(mdtype) != chunk_stat.used() ||
overhead_words(mdtype) != chunk_stat.overhead()) {
mismatch = true;
tty->print_cr("MetaspaceUtils::verify_metrics: counter mismatch for mdtype=%u:", mdtype);
tty->print_cr("Expected cap " SIZE_FORMAT ", used " SIZE_FORMAT ", overhead " SIZE_FORMAT ".",
capacity_words(mdtype), used_words(mdtype), overhead_words(mdtype));
tty->print_cr("Got cap " SIZE_FORMAT ", used " SIZE_FORMAT ", overhead " SIZE_FORMAT ".",
chunk_stat.cap(), chunk_stat.used(), chunk_stat.overhead());
tty->flush();
}
}
assert(mismatch == false, "MetaspaceUtils::verify_metrics: counter mismatch.");
#endif
}
// Metaspace methods
size_t Metaspace::_first_chunk_word_size = 0;
size_t Metaspace::_first_class_chunk_word_size = 0;
size_t Metaspace::_commit_alignment = 0;
size_t Metaspace::_reserve_alignment = 0;
VirtualSpaceList* Metaspace::_space_list = NULL;
VirtualSpaceList* Metaspace::_class_space_list = NULL;
ChunkManager* Metaspace::_chunk_manager_metadata = NULL;
ChunkManager* Metaspace::_chunk_manager_class = NULL;
#define VIRTUALSPACEMULTIPLIER 2
#ifdef _LP64
static const uint64_t UnscaledClassSpaceMax = (uint64_t(max_juint) + 1);
void Metaspace::set_narrow_klass_base_and_shift(address metaspace_base, address cds_base) {
assert(!DumpSharedSpaces, "narrow_klass is set by MetaspaceShared class.");
// Figure out the narrow_klass_base and the narrow_klass_shift. The
// narrow_klass_base is the lower of the metaspace base and the cds base
// (if cds is enabled). The narrow_klass_shift depends on the distance
// between the lower base and higher address.
address lower_base;
address higher_address;
#if INCLUDE_CDS
if (UseSharedSpaces) {
higher_address = MAX2((address)(cds_base + MetaspaceShared::core_spaces_size()),
(address)(metaspace_base + compressed_class_space_size()));
lower_base = MIN2(metaspace_base, cds_base);
} else
#endif
{
higher_address = metaspace_base + compressed_class_space_size();
lower_base = metaspace_base;
uint64_t klass_encoding_max = UnscaledClassSpaceMax << LogKlassAlignmentInBytes;
// If compressed class space fits in lower 32G, we don't need a base.
if (higher_address <= (address)klass_encoding_max) {
lower_base = 0; // Effectively lower base is zero.
}
}
Universe::set_narrow_klass_base(lower_base);
// CDS uses LogKlassAlignmentInBytes for narrow_klass_shift. See
// MetaspaceShared::initialize_dumptime_shared_and_meta_spaces() for
// how dump time narrow_klass_shift is set. Although, CDS can work
// with zero-shift mode also, to be consistent with AOT it uses
// LogKlassAlignmentInBytes for klass shift so archived java heap objects
// can be used at same time as AOT code.
if (!UseSharedSpaces
&& (uint64_t)(higher_address - lower_base) <= UnscaledClassSpaceMax) {
Universe::set_narrow_klass_shift(0);
} else {
Universe::set_narrow_klass_shift(LogKlassAlignmentInBytes);
}
AOTLoader::set_narrow_klass_shift();
}
#if INCLUDE_CDS
// Return TRUE if the specified metaspace_base and cds_base are close enough
// to work with compressed klass pointers.
bool Metaspace::can_use_cds_with_metaspace_addr(char* metaspace_base, address cds_base) {
assert(cds_base != 0 && UseSharedSpaces, "Only use with CDS");
assert(UseCompressedClassPointers, "Only use with CompressedKlassPtrs");
address lower_base = MIN2((address)metaspace_base, cds_base);
address higher_address = MAX2((address)(cds_base + MetaspaceShared::core_spaces_size()),
(address)(metaspace_base + compressed_class_space_size()));
return ((uint64_t)(higher_address - lower_base) <= UnscaledClassSpaceMax);
}
#endif
// Try to allocate the metaspace at the requested addr.
void Metaspace::allocate_metaspace_compressed_klass_ptrs(char* requested_addr, address cds_base) {
assert(!DumpSharedSpaces, "compress klass space is allocated by MetaspaceShared class.");
assert(using_class_space(), "called improperly");
assert(UseCompressedClassPointers, "Only use with CompressedKlassPtrs");
assert(compressed_class_space_size() < KlassEncodingMetaspaceMax,
"Metaspace size is too big");
assert_is_aligned(requested_addr, _reserve_alignment);
assert_is_aligned(cds_base, _reserve_alignment);
assert_is_aligned(compressed_class_space_size(), _reserve_alignment);
// Don't use large pages for the class space.
bool large_pages = false;
#if !(defined(AARCH64) || defined(AIX))
ReservedSpace metaspace_rs = ReservedSpace(compressed_class_space_size(),
_reserve_alignment,
large_pages,
requested_addr);
#else // AARCH64
ReservedSpace metaspace_rs;
// Our compressed klass pointers may fit nicely into the lower 32
// bits.
if ((uint64_t)requested_addr + compressed_class_space_size() < 4*G) {
metaspace_rs = ReservedSpace(compressed_class_space_size(),
_reserve_alignment,
large_pages,
requested_addr);
}
if (! metaspace_rs.is_reserved()) {
// Aarch64: Try to align metaspace so that we can decode a compressed
// klass with a single MOVK instruction. We can do this iff the
// compressed class base is a multiple of 4G.
// Aix: Search for a place where we can find memory. If we need to load
// the base, 4G alignment is helpful, too.
size_t increment = AARCH64_ONLY(4*)G;
for (char *a = align_up(requested_addr, increment);
a < (char*)(1024*G);
a += increment) {
if (a == (char *)(32*G)) {
// Go faster from here on. Zero-based is no longer possible.
increment = 4*G;
}
#if INCLUDE_CDS
if (UseSharedSpaces
&& ! can_use_cds_with_metaspace_addr(a, cds_base)) {
// We failed to find an aligned base that will reach. Fall
// back to using our requested addr.
metaspace_rs = ReservedSpace(compressed_class_space_size(),
_reserve_alignment,
large_pages,
requested_addr);
break;
}
#endif
metaspace_rs = ReservedSpace(compressed_class_space_size(),
_reserve_alignment,
large_pages,
a);
if (metaspace_rs.is_reserved())
break;
}
}
#endif // AARCH64
if (!metaspace_rs.is_reserved()) {
#if INCLUDE_CDS
if (UseSharedSpaces) {
size_t increment = align_up(1*G, _reserve_alignment);
// Keep trying to allocate the metaspace, increasing the requested_addr
// by 1GB each time, until we reach an address that will no longer allow
// use of CDS with compressed klass pointers.
char *addr = requested_addr;
while (!metaspace_rs.is_reserved() && (addr + increment > addr) &&
can_use_cds_with_metaspace_addr(addr + increment, cds_base)) {
addr = addr + increment;
metaspace_rs = ReservedSpace(compressed_class_space_size(),
_reserve_alignment, large_pages, addr);
}
}
#endif
// If no successful allocation then try to allocate the space anywhere. If
// that fails then OOM doom. At this point we cannot try allocating the
// metaspace as if UseCompressedClassPointers is off because too much
// initialization has happened that depends on UseCompressedClassPointers.
// So, UseCompressedClassPointers cannot be turned off at this point.
if (!metaspace_rs.is_reserved()) {
metaspace_rs = ReservedSpace(compressed_class_space_size(),
_reserve_alignment, large_pages);
if (!metaspace_rs.is_reserved()) {
vm_exit_during_initialization(err_msg("Could not allocate metaspace: " SIZE_FORMAT " bytes",
compressed_class_space_size()));
}
}
}
// If we got here then the metaspace got allocated.
MemTracker::record_virtual_memory_type((address)metaspace_rs.base(), mtClass);
#if INCLUDE_CDS
// Verify that we can use shared spaces. Otherwise, turn off CDS.
if (UseSharedSpaces && !can_use_cds_with_metaspace_addr(metaspace_rs.base(), cds_base)) {
FileMapInfo::stop_sharing_and_unmap(
"Could not allocate metaspace at a compatible address");
}
#endif
set_narrow_klass_base_and_shift((address)metaspace_rs.base(),
UseSharedSpaces ? (address)cds_base : 0);
initialize_class_space(metaspace_rs);
LogTarget(Trace, gc, metaspace) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
print_compressed_class_space(&ls, requested_addr);
}
}
void Metaspace::print_compressed_class_space(outputStream* st, const char* requested_addr) {
st->print_cr("Narrow klass base: " PTR_FORMAT ", Narrow klass shift: %d",
p2i(Universe::narrow_klass_base()), Universe::narrow_klass_shift());
if (_class_space_list != NULL) {
address base = (address)_class_space_list->current_virtual_space()->bottom();
st->print("Compressed class space size: " SIZE_FORMAT " Address: " PTR_FORMAT,
compressed_class_space_size(), p2i(base));
if (requested_addr != 0) {
st->print(" Req Addr: " PTR_FORMAT, p2i(requested_addr));
}
st->cr();
}
}
// For UseCompressedClassPointers the class space is reserved above the top of
// the Java heap. The argument passed in is at the base of the compressed space.
void Metaspace::initialize_class_space(ReservedSpace rs) {
// The reserved space size may be bigger because of alignment, esp with UseLargePages
assert(rs.size() >= CompressedClassSpaceSize,
SIZE_FORMAT " != " SIZE_FORMAT, rs.size(), CompressedClassSpaceSize);
assert(using_class_space(), "Must be using class space");
_class_space_list = new VirtualSpaceList(rs);
_chunk_manager_class = new ChunkManager(true/*is_class*/);
if (!_class_space_list->initialization_succeeded()) {
vm_exit_during_initialization("Failed to setup compressed class space virtual space list.");
}
}
#endif
void Metaspace::ergo_initialize() {
if (DumpSharedSpaces) {
// Using large pages when dumping the shared archive is currently not implemented.
FLAG_SET_ERGO(bool, UseLargePagesInMetaspace, false);
}
size_t page_size = os::vm_page_size();
if (UseLargePages && UseLargePagesInMetaspace) {
page_size = os::large_page_size();
}
_commit_alignment = page_size;
_reserve_alignment = MAX2(page_size, (size_t)os::vm_allocation_granularity());
// Do not use FLAG_SET_ERGO to update MaxMetaspaceSize, since this will
// override if MaxMetaspaceSize was set on the command line or not.
// This information is needed later to conform to the specification of the
// java.lang.management.MemoryUsage API.
//
// Ideally, we would be able to set the default value of MaxMetaspaceSize in
// globals.hpp to the aligned value, but this is not possible, since the
// alignment depends on other flags being parsed.
MaxMetaspaceSize = align_down_bounded(MaxMetaspaceSize, _reserve_alignment);
if (MetaspaceSize > MaxMetaspaceSize) {
MetaspaceSize = MaxMetaspaceSize;
}
MetaspaceSize = align_down_bounded(MetaspaceSize, _commit_alignment);
assert(MetaspaceSize <= MaxMetaspaceSize, "MetaspaceSize should be limited by MaxMetaspaceSize");
MinMetaspaceExpansion = align_down_bounded(MinMetaspaceExpansion, _commit_alignment);
MaxMetaspaceExpansion = align_down_bounded(MaxMetaspaceExpansion, _commit_alignment);
CompressedClassSpaceSize = align_down_bounded(CompressedClassSpaceSize, _reserve_alignment);
// Initial virtual space size will be calculated at global_initialize()
size_t min_metaspace_sz =
VIRTUALSPACEMULTIPLIER * InitialBootClassLoaderMetaspaceSize;
if (UseCompressedClassPointers) {
if ((min_metaspace_sz + CompressedClassSpaceSize) > MaxMetaspaceSize) {
if (min_metaspace_sz >= MaxMetaspaceSize) {
vm_exit_during_initialization("MaxMetaspaceSize is too small.");
} else {
FLAG_SET_ERGO(size_t, CompressedClassSpaceSize,
MaxMetaspaceSize - min_metaspace_sz);
}
}
} else if (min_metaspace_sz >= MaxMetaspaceSize) {
FLAG_SET_ERGO(size_t, InitialBootClassLoaderMetaspaceSize,
min_metaspace_sz);
}
set_compressed_class_space_size(CompressedClassSpaceSize);
}
void Metaspace::global_initialize() {
MetaspaceGC::initialize();
#if INCLUDE_CDS
if (DumpSharedSpaces) {
MetaspaceShared::initialize_dumptime_shared_and_meta_spaces();
} else if (UseSharedSpaces) {
// If any of the archived space fails to map, UseSharedSpaces
// is reset to false. Fall through to the
// (!DumpSharedSpaces && !UseSharedSpaces) case to set up class
// metaspace.
MetaspaceShared::initialize_runtime_shared_and_meta_spaces();
}
if (!DumpSharedSpaces && !UseSharedSpaces)
#endif // INCLUDE_CDS
{
#ifdef _LP64
if (using_class_space()) {
char* base = (char*)align_up(Universe::heap()->reserved_region().end(), _reserve_alignment);
allocate_metaspace_compressed_klass_ptrs(base, 0);
}
#endif // _LP64
}
// Initialize these before initializing the VirtualSpaceList
_first_chunk_word_size = InitialBootClassLoaderMetaspaceSize / BytesPerWord;
_first_chunk_word_size = align_word_size_up(_first_chunk_word_size);
// Make the first class chunk bigger than a medium chunk so it's not put
// on the medium chunk list. The next chunk will be small and progress
// from there. This size calculated by -version.
_first_class_chunk_word_size = MIN2((size_t)MediumChunk*6,
(CompressedClassSpaceSize/BytesPerWord)*2);
_first_class_chunk_word_size = align_word_size_up(_first_class_chunk_word_size);
// Arbitrarily set the initial virtual space to a multiple
// of the boot class loader size.
size_t word_size = VIRTUALSPACEMULTIPLIER * _first_chunk_word_size;
word_size = align_up(word_size, Metaspace::reserve_alignment_words());
// Initialize the list of virtual spaces.
_space_list = new VirtualSpaceList(word_size);
_chunk_manager_metadata = new ChunkManager(false/*metaspace*/);
if (!_space_list->initialization_succeeded()) {
vm_exit_during_initialization("Unable to setup metadata virtual space list.", NULL);
}
_tracer = new MetaspaceTracer();
}
void Metaspace::post_initialize() {
MetaspaceGC::post_initialize();
}
void Metaspace::verify_global_initialization() {
assert(space_list() != NULL, "Metadata VirtualSpaceList has not been initialized");
assert(chunk_manager_metadata() != NULL, "Metadata ChunkManager has not been initialized");
if (using_class_space()) {
assert(class_space_list() != NULL, "Class VirtualSpaceList has not been initialized");
assert(chunk_manager_class() != NULL, "Class ChunkManager has not been initialized");
}
}
size_t Metaspace::align_word_size_up(size_t word_size) {
size_t byte_size = word_size * wordSize;
return ReservedSpace::allocation_align_size_up(byte_size) / wordSize;
}
MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size,
MetaspaceObj::Type type, TRAPS) {
assert(!_frozen, "sanity");
if (HAS_PENDING_EXCEPTION) {
assert(false, "Should not allocate with exception pending");
return NULL; // caller does a CHECK_NULL too
}
assert(loader_data != NULL, "Should never pass around a NULL loader_data. "
"ClassLoaderData::the_null_class_loader_data() should have been used.");
MetadataType mdtype = (type == MetaspaceObj::ClassType) ? ClassType : NonClassType;
// Try to allocate metadata.
MetaWord* result = loader_data->metaspace_non_null()->allocate(word_size, mdtype);
if (result == NULL) {
tracer()->report_metaspace_allocation_failure(loader_data, word_size, type, mdtype);
// Allocation failed.
if (is_init_completed() && !(DumpSharedSpaces && THREAD->is_VM_thread())) {
// Only start a GC if the bootstrapping has completed.
// Also, we cannot GC if we are at the end of the CDS dumping stage which runs inside
// the VM thread.
// Try to clean out some memory and retry.
result = Universe::heap()->satisfy_failed_metadata_allocation(loader_data, word_size, mdtype);
}
}
if (result == NULL) {
if (DumpSharedSpaces) {
// CDS dumping keeps loading classes, so if we hit an OOM we probably will keep hitting OOM.
// We should abort to avoid generating a potentially bad archive.
tty->print_cr("Failed allocating metaspace object type %s of size " SIZE_FORMAT ". CDS dump aborted.",
MetaspaceObj::type_name(type), word_size * BytesPerWord);
tty->print_cr("Please increase MaxMetaspaceSize (currently " SIZE_FORMAT " bytes).", MaxMetaspaceSize);
vm_exit(1);
}
report_metadata_oome(loader_data, word_size, type, mdtype, CHECK_NULL);
}
// Zero initialize.
Copy::fill_to_words((HeapWord*)result, word_size, 0);
return result;
}
void Metaspace::report_metadata_oome(ClassLoaderData* loader_data, size_t word_size, MetaspaceObj::Type type, MetadataType mdtype, TRAPS) {
tracer()->report_metadata_oom(loader_data, word_size, type, mdtype);
// If result is still null, we are out of memory.
Log(gc, metaspace, freelist) log;
if (log.is_info()) {
log.info("Metaspace (%s) allocation failed for size " SIZE_FORMAT,
is_class_space_allocation(mdtype) ? "class" : "data", word_size);
ResourceMark rm;
if (log.is_debug()) {
if (loader_data->metaspace_or_null() != NULL) {
LogStream ls(log.debug());
loader_data->print_value_on(&ls);
}
}
LogStream ls(log.info());
// In case of an OOM, log out a short but still useful report.
MetaspaceUtils::print_basic_report(&ls, 0);
}
bool out_of_compressed_class_space = false;
if (is_class_space_allocation(mdtype)) {
ClassLoaderMetaspace* metaspace = loader_data->metaspace_non_null();
out_of_compressed_class_space =
MetaspaceUtils::committed_bytes(Metaspace::ClassType) +
(metaspace->class_chunk_size(word_size) * BytesPerWord) >
CompressedClassSpaceSize;
}
// -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support
const char* space_string = out_of_compressed_class_space ?
"Compressed class space" : "Metaspace";
report_java_out_of_memory(space_string);
if (JvmtiExport::should_post_resource_exhausted()) {
JvmtiExport::post_resource_exhausted(
JVMTI_RESOURCE_EXHAUSTED_OOM_ERROR,
space_string);
}
if (!is_init_completed()) {
vm_exit_during_initialization("OutOfMemoryError", space_string);
}
if (out_of_compressed_class_space) {
THROW_OOP(Universe::out_of_memory_error_class_metaspace());
} else {
THROW_OOP(Universe::out_of_memory_error_metaspace());
}
}
const char* Metaspace::metadata_type_name(Metaspace::MetadataType mdtype) {
switch (mdtype) {
case Metaspace::ClassType: return "Class";
case Metaspace::NonClassType: return "Metadata";
default:
assert(false, "Got bad mdtype: %d", (int) mdtype);
return NULL;
}
}
void Metaspace::purge(MetadataType mdtype) {
get_space_list(mdtype)->purge(get_chunk_manager(mdtype));
}
void Metaspace::purge() {
MutexLockerEx cl(MetaspaceExpand_lock,
Mutex::_no_safepoint_check_flag);
purge(NonClassType);
if (using_class_space()) {
purge(ClassType);
}
}
bool Metaspace::contains(const void* ptr) {
if (MetaspaceShared::is_in_shared_metaspace(ptr)) {
return true;
}
return contains_non_shared(ptr);
}
bool Metaspace::contains_non_shared(const void* ptr) {
if (using_class_space() && get_space_list(ClassType)->contains(ptr)) {
return true;
}
return get_space_list(NonClassType)->contains(ptr);
}
// ClassLoaderMetaspace
ClassLoaderMetaspace::ClassLoaderMetaspace(Mutex* lock, Metaspace::MetaspaceType type)
: _lock(lock)
, _space_type(type)
, _vsm(NULL)
, _class_vsm(NULL)
{
initialize(lock, type);
}
ClassLoaderMetaspace::~ClassLoaderMetaspace() {
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_metaspace_deaths));
delete _vsm;
if (Metaspace::using_class_space()) {
delete _class_vsm;
}
}
void ClassLoaderMetaspace::initialize_first_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype) {
Metachunk* chunk = get_initialization_chunk(type, mdtype);
if (chunk != NULL) {
// Add to this manager's list of chunks in use and make it the current_chunk().
get_space_manager(mdtype)->add_chunk(chunk, true);
}
}
Metachunk* ClassLoaderMetaspace::get_initialization_chunk(Metaspace::MetaspaceType type, Metaspace::MetadataType mdtype) {
size_t chunk_word_size = get_space_manager(mdtype)->get_initial_chunk_size(type);
// Get a chunk from the chunk freelist
Metachunk* chunk = Metaspace::get_chunk_manager(mdtype)->chunk_freelist_allocate(chunk_word_size);
if (chunk == NULL) {
chunk = Metaspace::get_space_list(mdtype)->get_new_chunk(chunk_word_size,
get_space_manager(mdtype)->medium_chunk_bunch());
}
return chunk;
}
void ClassLoaderMetaspace::initialize(Mutex* lock, Metaspace::MetaspaceType type) {
Metaspace::verify_global_initialization();
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_metaspace_births));
// Allocate SpaceManager for metadata objects.
_vsm = new SpaceManager(Metaspace::NonClassType, type, lock);
if (Metaspace::using_class_space()) {
// Allocate SpaceManager for classes.
_class_vsm = new SpaceManager(Metaspace::ClassType, type, lock);
}
MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
// Allocate chunk for metadata objects
initialize_first_chunk(type, Metaspace::NonClassType);
// Allocate chunk for class metadata objects
if (Metaspace::using_class_space()) {
initialize_first_chunk(type, Metaspace::ClassType);
}
}
MetaWord* ClassLoaderMetaspace::allocate(size_t word_size, Metaspace::MetadataType mdtype) {
Metaspace::assert_not_frozen();
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_allocs));
// Don't use class_vsm() unless UseCompressedClassPointers is true.
if (Metaspace::is_class_space_allocation(mdtype)) {
return class_vsm()->allocate(word_size);
} else {
return vsm()->allocate(word_size);
}
}
MetaWord* ClassLoaderMetaspace::expand_and_allocate(size_t word_size, Metaspace::MetadataType mdtype) {
Metaspace::assert_not_frozen();
size_t delta_bytes = MetaspaceGC::delta_capacity_until_GC(word_size * BytesPerWord);
assert(delta_bytes > 0, "Must be");
size_t before = 0;
size_t after = 0;
MetaWord* res;
bool incremented;
// Each thread increments the HWM at most once. Even if the thread fails to increment
// the HWM, an allocation is still attempted. This is because another thread must then
// have incremented the HWM and therefore the allocation might still succeed.
do {
incremented = MetaspaceGC::inc_capacity_until_GC(delta_bytes, &after, &before);
res = allocate(word_size, mdtype);
} while (!incremented && res == NULL);
if (incremented) {
Metaspace::tracer()->report_gc_threshold(before, after,
MetaspaceGCThresholdUpdater::ExpandAndAllocate);
log_trace(gc, metaspace)("Increase capacity to GC from " SIZE_FORMAT " to " SIZE_FORMAT, before, after);
}
return res;
}
size_t ClassLoaderMetaspace::allocated_blocks_bytes() const {
return (vsm()->used_words() +
(Metaspace::using_class_space() ? class_vsm()->used_words() : 0)) * BytesPerWord;
}
size_t ClassLoaderMetaspace::allocated_chunks_bytes() const {
return (vsm()->capacity_words() +
(Metaspace::using_class_space() ? class_vsm()->capacity_words() : 0)) * BytesPerWord;
}
void ClassLoaderMetaspace::deallocate(MetaWord* ptr, size_t word_size, bool is_class) {
Metaspace::assert_not_frozen();
assert(!SafepointSynchronize::is_at_safepoint()
|| Thread::current()->is_VM_thread(), "should be the VM thread");
DEBUG_ONLY(Atomic::inc(&g_internal_statistics.num_external_deallocs));
MutexLockerEx ml(vsm()->lock(), Mutex::_no_safepoint_check_flag);
if (is_class && Metaspace::using_class_space()) {
class_vsm()->deallocate(ptr, word_size);
} else {
vsm()->deallocate(ptr, word_size);
}
}
size_t ClassLoaderMetaspace::class_chunk_size(size_t word_size) {
assert(Metaspace::using_class_space(), "Has to use class space");
return class_vsm()->calc_chunk_size(word_size);
}
void ClassLoaderMetaspace::print_on(outputStream* out) const {
// Print both class virtual space counts and metaspace.
if (Verbose) {
vsm()->print_on(out);
if (Metaspace::using_class_space()) {
class_vsm()->print_on(out);
}
}
}
void ClassLoaderMetaspace::verify() {
vsm()->verify();
if (Metaspace::using_class_space()) {
class_vsm()->verify();
}
}
void ClassLoaderMetaspace::add_to_statistics_locked(ClassLoaderMetaspaceStatistics* out) const {
assert_lock_strong(lock());
vsm()->add_to_statistics_locked(&out->nonclass_sm_stats());
if (Metaspace::using_class_space()) {
class_vsm()->add_to_statistics_locked(&out->class_sm_stats());
}
}
void ClassLoaderMetaspace::add_to_statistics(ClassLoaderMetaspaceStatistics* out) const {
MutexLockerEx cl(lock(), Mutex::_no_safepoint_check_flag);
add_to_statistics_locked(out);
}
#ifdef ASSERT
static void do_verify_chunk(Metachunk* chunk) {
guarantee(chunk != NULL, "Sanity");
// Verify chunk itself; then verify that it is consistent with the
// occupany map of its containing node.
chunk->verify();
VirtualSpaceNode* const vsn = chunk->container();
OccupancyMap* const ocmap = vsn->occupancy_map();
ocmap->verify_for_chunk(chunk);
}
#endif
static void do_update_in_use_info_for_chunk(Metachunk* chunk, bool inuse) {
chunk->set_is_tagged_free(!inuse);
OccupancyMap* const ocmap = chunk->container()->occupancy_map();
ocmap->set_region_in_use((MetaWord*)chunk, chunk->word_size(), inuse);
}
/////////////// Unit tests ///////////////
#ifndef PRODUCT
class TestMetaspaceUtilsTest : AllStatic {
public:
static void test_reserved() {
size_t reserved = MetaspaceUtils::reserved_bytes();
assert(reserved > 0, "assert");
size_t committed = MetaspaceUtils::committed_bytes();
assert(committed <= reserved, "assert");
size_t reserved_metadata = MetaspaceUtils::reserved_bytes(Metaspace::NonClassType);
assert(reserved_metadata > 0, "assert");
assert(reserved_metadata <= reserved, "assert");
if (UseCompressedClassPointers) {
size_t reserved_class = MetaspaceUtils::reserved_bytes(Metaspace::ClassType);
assert(reserved_class > 0, "assert");
assert(reserved_class < reserved, "assert");
}
}
static void test_committed() {
size_t committed = MetaspaceUtils::committed_bytes();
assert(committed > 0, "assert");
size_t reserved = MetaspaceUtils::reserved_bytes();
assert(committed <= reserved, "assert");
size_t committed_metadata = MetaspaceUtils::committed_bytes(Metaspace::NonClassType);
assert(committed_metadata > 0, "assert");
assert(committed_metadata <= committed, "assert");
if (UseCompressedClassPointers) {
size_t committed_class = MetaspaceUtils::committed_bytes(Metaspace::ClassType);
assert(committed_class > 0, "assert");
assert(committed_class < committed, "assert");
}
}
static void test_virtual_space_list_large_chunk() {
VirtualSpaceList* vs_list = new VirtualSpaceList(os::vm_allocation_granularity());
MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
// A size larger than VirtualSpaceSize (256k) and add one page to make it _not_ be
// vm_allocation_granularity aligned on Windows.
size_t large_size = (size_t)(2*256*K + (os::vm_page_size()/BytesPerWord));
large_size += (os::vm_page_size()/BytesPerWord);
vs_list->get_new_chunk(large_size, 0);
}
static void test() {
test_reserved();
test_committed();
test_virtual_space_list_large_chunk();
}
};
void TestMetaspaceUtils_test() {
TestMetaspaceUtilsTest::test();
}
class TestVirtualSpaceNodeTest {
static void chunk_up(size_t words_left, size_t& num_medium_chunks,
size_t& num_small_chunks,
size_t& num_specialized_chunks) {
num_medium_chunks = words_left / MediumChunk;
words_left = words_left % MediumChunk;
num_small_chunks = words_left / SmallChunk;
words_left = words_left % SmallChunk;
// how many specialized chunks can we get?
num_specialized_chunks = words_left / SpecializedChunk;
assert(words_left % SpecializedChunk == 0, "should be nothing left");
}
public:
static void test() {
MutexLockerEx ml(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
const size_t vsn_test_size_words = MediumChunk * 4;
const size_t vsn_test_size_bytes = vsn_test_size_words * BytesPerWord;
// The chunk sizes must be multiples of eachother, or this will fail
STATIC_ASSERT(MediumChunk % SmallChunk == 0);
STATIC_ASSERT(SmallChunk % SpecializedChunk == 0);
{ // No committed memory in VSN
ChunkManager cm(false);
VirtualSpaceNode vsn(false, vsn_test_size_bytes);
vsn.initialize();
vsn.retire(&cm);
assert(cm.sum_free_chunks_count() == 0, "did not commit any memory in the VSN");
}
{ // All of VSN is committed, half is used by chunks
ChunkManager cm(false);
VirtualSpaceNode vsn(false, vsn_test_size_bytes);
vsn.initialize();
vsn.expand_by(vsn_test_size_words, vsn_test_size_words);
vsn.get_chunk_vs(MediumChunk);
vsn.get_chunk_vs(MediumChunk);
vsn.retire(&cm);
assert(cm.sum_free_chunks_count() == 2, "should have been memory left for 2 medium chunks");
assert(cm.sum_free_chunks() == 2*MediumChunk, "sizes should add up");
}
const size_t page_chunks = 4 * (size_t)os::vm_page_size() / BytesPerWord;
// This doesn't work for systems with vm_page_size >= 16K.
if (page_chunks < MediumChunk) {
// 4 pages of VSN is committed, some is used by chunks
ChunkManager cm(false);
VirtualSpaceNode vsn(false, vsn_test_size_bytes);
vsn.initialize();
vsn.expand_by(page_chunks, page_chunks);
vsn.get_chunk_vs(SmallChunk);
vsn.get_chunk_vs(SpecializedChunk);
vsn.retire(&cm);
// committed - used = words left to retire
const size_t words_left = page_chunks - SmallChunk - SpecializedChunk;
size_t num_medium_chunks, num_small_chunks, num_spec_chunks;
chunk_up(words_left, num_medium_chunks, num_small_chunks, num_spec_chunks);
assert(num_medium_chunks == 0, "should not get any medium chunks");
assert(cm.sum_free_chunks_count() == (num_small_chunks + num_spec_chunks), "should be space for 3 chunks");
assert(cm.sum_free_chunks() == words_left, "sizes should add up");
}
{ // Half of VSN is committed, a humongous chunk is used
ChunkManager cm(false);
VirtualSpaceNode vsn(false, vsn_test_size_bytes);
vsn.initialize();
vsn.expand_by(MediumChunk * 2, MediumChunk * 2);
vsn.get_chunk_vs(MediumChunk + SpecializedChunk); // Humongous chunks will be aligned up to MediumChunk + SpecializedChunk
vsn.retire(&cm);
const size_t words_left = MediumChunk * 2 - (MediumChunk + SpecializedChunk);
size_t num_medium_chunks, num_small_chunks, num_spec_chunks;
chunk_up(words_left, num_medium_chunks, num_small_chunks, num_spec_chunks);
assert(num_medium_chunks == 0, "should not get any medium chunks");
assert(cm.sum_free_chunks_count() == (num_small_chunks + num_spec_chunks), "should be space for 3 chunks");
assert(cm.sum_free_chunks() == words_left, "sizes should add up");
}
}
#define assert_is_available_positive(word_size) \
assert(vsn.is_available(word_size), \
#word_size ": " PTR_FORMAT " bytes were not available in " \
"VirtualSpaceNode [" PTR_FORMAT ", " PTR_FORMAT ")", \
(uintptr_t)(word_size * BytesPerWord), p2i(vsn.bottom()), p2i(vsn.end()));
#define assert_is_available_negative(word_size) \
assert(!vsn.is_available(word_size), \
#word_size ": " PTR_FORMAT " bytes should not be available in " \
"VirtualSpaceNode [" PTR_FORMAT ", " PTR_FORMAT ")", \
(uintptr_t)(word_size * BytesPerWord), p2i(vsn.bottom()), p2i(vsn.end()));
static void test_is_available_positive() {
// Reserve some memory.
VirtualSpaceNode vsn(false, os::vm_allocation_granularity());
assert(vsn.initialize(), "Failed to setup VirtualSpaceNode");
// Commit some memory.
size_t commit_word_size = os::vm_allocation_granularity() / BytesPerWord;
bool expanded = vsn.expand_by(commit_word_size, commit_word_size);
assert(expanded, "Failed to commit");
// Check that is_available accepts the committed size.
assert_is_available_positive(commit_word_size);
// Check that is_available accepts half the committed size.
size_t expand_word_size = commit_word_size / 2;
assert_is_available_positive(expand_word_size);
}
static void test_is_available_negative() {
// Reserve some memory.
VirtualSpaceNode vsn(false, os::vm_allocation_granularity());
assert(vsn.initialize(), "Failed to setup VirtualSpaceNode");
// Commit some memory.
size_t commit_word_size = os::vm_allocation_granularity() / BytesPerWord;
bool expanded = vsn.expand_by(commit_word_size, commit_word_size);
assert(expanded, "Failed to commit");
// Check that is_available doesn't accept a too large size.
size_t two_times_commit_word_size = commit_word_size * 2;
assert_is_available_negative(two_times_commit_word_size);
}
static void test_is_available_overflow() {
// Reserve some memory.
VirtualSpaceNode vsn(false, os::vm_allocation_granularity());
assert(vsn.initialize(), "Failed to setup VirtualSpaceNode");
// Commit some memory.
size_t commit_word_size = os::vm_allocation_granularity() / BytesPerWord;
bool expanded = vsn.expand_by(commit_word_size, commit_word_size);
assert(expanded, "Failed to commit");
// Calculate a size that will overflow the virtual space size.
void* virtual_space_max = (void*)(uintptr_t)-1;
size_t bottom_to_max = pointer_delta(virtual_space_max, vsn.bottom(), 1);
size_t overflow_size = bottom_to_max + BytesPerWord;
size_t overflow_word_size = overflow_size / BytesPerWord;
// Check that is_available can handle the overflow.
assert_is_available_negative(overflow_word_size);
}
static void test_is_available() {
TestVirtualSpaceNodeTest::test_is_available_positive();
TestVirtualSpaceNodeTest::test_is_available_negative();
TestVirtualSpaceNodeTest::test_is_available_overflow();
}
};
// The following test is placed here instead of a gtest / unittest file
// because the ChunkManager class is only available in this file.
void ChunkManager_test_list_index() {
{
// Test previous bug where a query for a humongous class metachunk,
// incorrectly matched the non-class medium metachunk size.
{
ChunkManager manager(true);
assert(MediumChunk > ClassMediumChunk, "Precondition for test");
ChunkIndex index = manager.list_index(MediumChunk);
assert(index == HumongousIndex,
"Requested size is larger than ClassMediumChunk,"
" so should return HumongousIndex. Got index: %d", (int)index);
}
// Check the specified sizes as well.
{
ChunkManager manager(true);
assert(manager.list_index(ClassSpecializedChunk) == SpecializedIndex, "sanity");
assert(manager.list_index(ClassSmallChunk) == SmallIndex, "sanity");
assert(manager.list_index(ClassMediumChunk) == MediumIndex, "sanity");
assert(manager.list_index(ClassMediumChunk + ClassSpecializedChunk) == HumongousIndex, "sanity");
}
{
ChunkManager manager(false);
assert(manager.list_index(SpecializedChunk) == SpecializedIndex, "sanity");
assert(manager.list_index(SmallChunk) == SmallIndex, "sanity");
assert(manager.list_index(MediumChunk) == MediumIndex, "sanity");
assert(manager.list_index(MediumChunk + SpecializedChunk) == HumongousIndex, "sanity");
}
}
}
#endif // !PRODUCT
#ifdef ASSERT
// The following test is placed here instead of a gtest / unittest file
// because the ChunkManager class is only available in this file.
class SpaceManagerTest : AllStatic {
friend void SpaceManager_test_adjust_initial_chunk_size();
static void test_adjust_initial_chunk_size(bool is_class) {
const size_t smallest = SpaceManager::smallest_chunk_size(is_class);
const size_t normal = SpaceManager::small_chunk_size(is_class);
const size_t medium = SpaceManager::medium_chunk_size(is_class);
#define test_adjust_initial_chunk_size(value, expected, is_class_value) \
do { \
size_t v = value; \
size_t e = expected; \
assert(SpaceManager::adjust_initial_chunk_size(v, (is_class_value)) == e, \
"Expected: " SIZE_FORMAT " got: " SIZE_FORMAT, e, v); \
} while (0)
// Smallest (specialized)
test_adjust_initial_chunk_size(1, smallest, is_class);
test_adjust_initial_chunk_size(smallest - 1, smallest, is_class);
test_adjust_initial_chunk_size(smallest, smallest, is_class);
// Small
test_adjust_initial_chunk_size(smallest + 1, normal, is_class);
test_adjust_initial_chunk_size(normal - 1, normal, is_class);
test_adjust_initial_chunk_size(normal, normal, is_class);
// Medium
test_adjust_initial_chunk_size(normal + 1, medium, is_class);
test_adjust_initial_chunk_size(medium - 1, medium, is_class);
test_adjust_initial_chunk_size(medium, medium, is_class);
// Humongous
test_adjust_initial_chunk_size(medium + 1, medium + 1, is_class);
#undef test_adjust_initial_chunk_size
}
static void test_adjust_initial_chunk_size() {
test_adjust_initial_chunk_size(false);
test_adjust_initial_chunk_size(true);
}
};
void SpaceManager_test_adjust_initial_chunk_size() {
SpaceManagerTest::test_adjust_initial_chunk_size();
}
#endif // ASSERT
struct chunkmanager_statistics_t {
int num_specialized_chunks;
int num_small_chunks;
int num_medium_chunks;
int num_humongous_chunks;
};
extern void test_metaspace_retrieve_chunkmanager_statistics(Metaspace::MetadataType mdType, chunkmanager_statistics_t* out) {
ChunkManager* const chunk_manager = Metaspace::get_chunk_manager(mdType);
ChunkManagerStatistics stat;
chunk_manager->collect_statistics(&stat);
out->num_specialized_chunks = (int)stat.chunk_stats(SpecializedIndex).num();
out->num_small_chunks = (int)stat.chunk_stats(SmallIndex).num();
out->num_medium_chunks = (int)stat.chunk_stats(MediumIndex).num();
out->num_humongous_chunks = (int)stat.chunk_stats(HumongousIndex).num();
}
struct chunk_geometry_t {
size_t specialized_chunk_word_size;
size_t small_chunk_word_size;
size_t medium_chunk_word_size;
};
extern void test_metaspace_retrieve_chunk_geometry(Metaspace::MetadataType mdType, chunk_geometry_t* out) {
if (mdType == Metaspace::NonClassType) {
out->specialized_chunk_word_size = SpecializedChunk;
out->small_chunk_word_size = SmallChunk;
out->medium_chunk_word_size = MediumChunk;
} else {
out->specialized_chunk_word_size = ClassSpecializedChunk;
out->small_chunk_word_size = ClassSmallChunk;
out->medium_chunk_word_size = ClassMediumChunk;
}
}