8221480: jcmd VM.metaspace shall print limits in basic mode
Reviewed-by: adinn, rehn
/*
* Copyright (c) 2011, 2019, 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
* questions.
*
*/
#include "precompiled.hpp"
#include "aot/aotLoader.hpp"
#include "classfile/classLoaderDataGraph.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/filemap.hpp"
#include "memory/metaspace.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/metachunk.hpp"
#include "memory/metaspace/metaspaceCommon.hpp"
#include "memory/metaspace/printCLDMetaspaceInfoClosure.hpp"
#include "memory/metaspace/spaceManager.hpp"
#include "memory/metaspace/virtualSpaceList.hpp"
#include "memory/metaspaceShared.hpp"
#include "memory/metaspaceTracer.hpp"
#include "memory/universe.hpp"
#include "runtime/init.hpp"
#include "runtime/orderAccess.hpp"
#include "services/memTracker.hpp"
#include "utilities/copy.hpp"
#include "utilities/debug.hpp"
#include "utilities/formatBuffer.hpp"
#include "utilities/globalDefinitions.hpp"
using namespace metaspace;
MetaWord* last_allocated = 0;
size_t Metaspace::_compressed_class_space_size;
const MetaspaceTracer* Metaspace::_tracer = NULL;
DEBUG_ONLY(bool Metaspace::_frozen = false;)
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::UnsafeAnonymousMetaspaceType: s = "UnsafeAnonymous"; break;
case Metaspace::ReflectionMetaspaceType: s = "Reflection"; break;
default: ShouldNotReachHere();
}
return s;
}
volatile size_t MetaspaceGC::_capacity_until_GC = 0;
uint MetaspaceGC::_shrink_factor = 0;
bool MetaspaceGC::_should_concurrent_collect = false;
// BlockFreelist methods
// VirtualSpaceNode methods
// 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;
}
// Try to increase the _capacity_until_GC limit counter by v bytes.
// Returns true if it succeeded. It may fail if either another thread
// concurrently increased the limit or the new limit would be larger
// than MaxMetaspaceSize.
// On success, optionally returns new and old metaspace capacity in
// new_cap_until_GC and old_cap_until_GC respectively.
// On error, optionally sets can_retry to indicate whether if there is
// actually enough space remaining to satisfy the request.
bool MetaspaceGC::inc_capacity_until_GC(size_t v, size_t* new_cap_until_GC, size_t* old_cap_until_GC, bool* can_retry) {
assert_is_aligned(v, Metaspace::commit_alignment());
size_t old_capacity_until_GC = _capacity_until_GC;
size_t new_value = old_capacity_until_GC + v;
if (new_value < old_capacity_until_GC) {
// The addition wrapped around, set new_value to aligned max value.
new_value = align_down(max_uintx, Metaspace::commit_alignment());
}
if (new_value > MaxMetaspaceSize) {
if (can_retry != NULL) {
*can_retry = false;
}
return false;
}
if (can_retry != NULL) {
*can_retry = true;
}
size_t prev_value = Atomic::cmpxchg(new_value, &_capacity_until_GC, old_capacity_until_GC);
if (old_capacity_until_GC != prev_value) {
return false;
}
if (new_cap_until_GC != NULL) {
*new_cap_until_GC = new_value;
}
if (old_cap_until_GC != NULL) {
*old_cap_until_GC = old_capacity_until_GC;
}
return true;
}
size_t MetaspaceGC::dec_capacity_until_GC(size_t v) {
assert_is_aligned(v, Metaspace::commit_alignment());
return Atomic::sub(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(MaxMetaspaceSize));
// 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(MaxMetaspaceSize));
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);
}
}
// 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;
}
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);
}
}
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 ");
}
}
}
static void print_basic_switches(outputStream* out, size_t scale) {
out->print("MaxMetaspaceSize: ");
if (MaxMetaspaceSize >= (max_uintx) - (2 * os::vm_page_size())) {
// aka "very big". Default is max_uintx, but due to rounding in arg parsing the real
// value is smaller.
out->print("unlimited");
} else {
print_human_readable_size(out, MaxMetaspaceSize, scale);
}
out->cr();
if (Metaspace::using_class_space()) {
out->print("CompressedClassSpaceSize: ");
print_human_readable_size(out, CompressedClassSpaceSize, scale);
}
out->cr();
}
// 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_bytes(), scale);
out->cr();
if (Metaspace::using_class_space()) {
out->print(" Class: ");
print_human_readable_size(out, Metaspace::chunk_manager_class()->free_chunks_total_bytes(), scale);
out->cr();
out->print(" Both: ");
print_human_readable_size(out, Metaspace::chunk_manager_class()->free_chunks_total_bytes() +
Metaspace::chunk_manager_metadata()->free_chunks_total_bytes(), scale);
out->cr();
}
out->cr();
// Print basic settings
print_basic_switches(out, scale);
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_classes = (flags & rf_show_classes) > 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_classes, print_by_chunktype);
if (print_loaders) {
out->cr();
out->print_cr("Usage per loader:");
out->cr();
}
ClassLoaderDataGraph::loaded_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->print_cr("Number of chunks added to freelist: " UINTX_FORMAT ".",
g_internal_statistics.num_chunks_added_to_freelist);
out->print_cr("Number of chunks removed from freelist: " UINTX_FORMAT ".",
g_internal_statistics.num_chunks_removed_from_freelist);
out->print_cr("Number of chunk merges: " UINTX_FORMAT ", split-ups: " UINTX_FORMAT ".",
g_internal_statistics.num_chunk_merges, g_internal_statistics.num_chunk_splits);
out->cr();
#endif
// Print some interesting settings
out->cr();
out->cr();
print_basic_switches(out, scale);
out->cr();
out->print("InitialBootClassLoaderMetaspaceSize: ");
print_human_readable_size(out, InitialBootClassLoaderMetaspaceSize, 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() {
#ifdef ASSERT
Metaspace::chunk_manager_metadata()->verify(false);
if (Metaspace::using_class_space()) {
Metaspace::chunk_manager_class()->verify(false);
}
#endif
}
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
}
// Utils to check if a pointer or range is part of a committed metaspace region.
metaspace::VirtualSpaceNode* MetaspaceUtils::find_enclosing_virtual_space(const void* p) {
MutexLockerEx cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
VirtualSpaceNode* vsn = Metaspace::space_list()->find_enclosing_space(p);
if (Metaspace::using_class_space() && vsn == NULL) {
vsn = Metaspace::class_space_list()->find_enclosing_space(p);
}
return vsn;
}
bool MetaspaceUtils::is_range_in_committed(const void* from, const void* to) {
#if INCLUDE_CDS
if (UseSharedSpaces) {
for (int idx = MetaspaceShared::ro; idx <= MetaspaceShared::mc; idx++) {
if (FileMapInfo::current_info()->is_in_shared_region(from, idx)) {
return FileMapInfo::current_info()->is_in_shared_region(to, idx);
}
}
}
#endif
VirtualSpaceNode* vsn = find_enclosing_virtual_space(from);
return (vsn != NULL) && vsn->contains(to);
}
// 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");
assert(!(DumpSharedSpaces && THREAD->is_VM_thread()), "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()) {
// Only start a GC if the bootstrapping has completed.
// Try to clean out some heap memory and retry. This can prevent premature
// expansion of the metaspace.
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.
vm_exit_during_cds_dumping(err_msg("Failed allocating metaspace object type %s of size " SIZE_FORMAT ". CDS dump aborted.",
MetaspaceObj::type_name(type), word_size * BytesPerWord),
err_msg("Please increase MaxMetaspaceSize (currently " SIZE_FORMAT " bytes).", MaxMetaspaceSize));
}
report_metadata_oome(loader_data, word_size, type, mdtype, THREAD);
assert(HAS_PENDING_EXCEPTION, "sanity");
return 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, oom) 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)
: _space_type(type)
, _lock(lock)
, _vsm(NULL)
, _class_vsm(NULL)
{
initialize(lock, type);
}
ClassLoaderMetaspace::~ClassLoaderMetaspace() {
Metaspace::assert_not_frozen();
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;
bool can_retry = true;
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, &can_retry);
res = allocate(word_size, mdtype);
} while (!incremented && res == NULL && can_retry);
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);
}
/////////////// 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();
}
#endif // !PRODUCT
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;
}
}