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jdk/src/hotspot/share/memory/metaspace.cpp
Vladimir Kozlov 694acedf18 8264805: Remove the experimental Ahead-of-Time Compiler 
Reviewed-by: coleenp, erikj, stefank, iignatyev, dholmes, aph, shade, iklam, mchung, iveresov
2021-04-27 01:12:18 +00:00

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/*
* Copyright (c) 2011, 2021, 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 "cds/metaspaceShared.hpp"
#include "classfile/classLoaderData.hpp"
#include "gc/shared/collectedHeap.hpp"
#include "logging/log.hpp"
#include "logging/logStream.hpp"
#include "memory/classLoaderMetaspace.hpp"
#include "memory/metaspace.hpp"
#include "memory/metaspace/chunkHeaderPool.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/commitLimiter.hpp"
#include "memory/metaspace/metaspaceCommon.hpp"
#include "memory/metaspace/metaspaceContext.hpp"
#include "memory/metaspace/metaspaceReporter.hpp"
#include "memory/metaspace/metaspaceSettings.hpp"
#include "memory/metaspace/metaspaceSizesSnapshot.hpp"
#include "memory/metaspace/runningCounters.hpp"
#include "memory/metaspace/virtualSpaceList.hpp"
#include "memory/metaspaceTracer.hpp"
#include "memory/metaspaceUtils.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "oops/compressedOops.hpp"
#include "prims/jvmtiExport.hpp"
#include "runtime/atomic.hpp"
#include "runtime/globals_extension.hpp"
#include "runtime/init.hpp"
#include "runtime/java.hpp"
#include "services/memTracker.hpp"
#include "utilities/copy.hpp"
#include "utilities/debug.hpp"
#include "utilities/formatBuffer.hpp"
#include "utilities/globalDefinitions.hpp"
using metaspace::ChunkManager;
using metaspace::CommitLimiter;
using metaspace::MetaspaceContext;
using metaspace::MetaspaceReporter;
using metaspace::RunningCounters;
using metaspace::VirtualSpaceList;
size_t MetaspaceUtils::used_words() {
return RunningCounters::used_words();
}
size_t MetaspaceUtils::used_words(Metaspace::MetadataType mdtype) {
return mdtype == Metaspace::ClassType ? RunningCounters::used_words_class() : RunningCounters::used_words_nonclass();
}
size_t MetaspaceUtils::reserved_words() {
return RunningCounters::reserved_words();
}
size_t MetaspaceUtils::reserved_words(Metaspace::MetadataType mdtype) {
return mdtype == Metaspace::ClassType ? RunningCounters::reserved_words_class() : RunningCounters::reserved_words_nonclass();
}
size_t MetaspaceUtils::committed_words() {
return RunningCounters::committed_words();
}
size_t MetaspaceUtils::committed_words(Metaspace::MetadataType mdtype) {
return mdtype == Metaspace::ClassType ? RunningCounters::committed_words_class() : RunningCounters::committed_words_nonclass();
}
void MetaspaceUtils::print_metaspace_change(const metaspace::MetaspaceSizesSnapshot& pre_meta_values) {
const metaspace::MetaspaceSizesSnapshot meta_values;
// We print used and committed since these are the most useful at-a-glance vitals for Metaspace:
// - used tells you how much memory is actually used for metadata
// - committed tells you how much memory is committed for the purpose of metadata
// The difference between those two would be waste, which can have various forms (freelists,
// unused parts of committed chunks etc)
//
// Left out is reserved, since this is not as exciting as the first two values: for class space,
// it is a constant (to uninformed users, often confusingly large). For non-class space, it would
// be interesting since free chunks can be uncommitted, but for now it is left out.
if (Metaspace::using_class_space()) {
log_info(gc, metaspace)(HEAP_CHANGE_FORMAT" "
HEAP_CHANGE_FORMAT" "
HEAP_CHANGE_FORMAT,
HEAP_CHANGE_FORMAT_ARGS("Metaspace",
pre_meta_values.used(),
pre_meta_values.committed(),
meta_values.used(),
meta_values.committed()),
HEAP_CHANGE_FORMAT_ARGS("NonClass",
pre_meta_values.non_class_used(),
pre_meta_values.non_class_committed(),
meta_values.non_class_used(),
meta_values.non_class_committed()),
HEAP_CHANGE_FORMAT_ARGS("Class",
pre_meta_values.class_used(),
pre_meta_values.class_committed(),
meta_values.class_used(),
meta_values.class_committed()));
} else {
log_info(gc, metaspace)(HEAP_CHANGE_FORMAT,
HEAP_CHANGE_FORMAT_ARGS("Metaspace",
pre_meta_values.used(),
pre_meta_values.committed(),
meta_values.used(),
meta_values.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) {
MetaspaceReporter::print_basic_report(out, scale);
}
// Prints a report about the current metaspace state.
// Optional parts can be enabled via flags.
// Function will walk the CLDG and will lock the expand lock; if that is not
// convenient, use print_basic_report() instead.
void MetaspaceUtils::print_report(outputStream* out, size_t scale) {
const int flags =
(int)MetaspaceReporter::Option::ShowLoaders |
(int)MetaspaceReporter::Option::BreakDownByChunkType |
(int)MetaspaceReporter::Option::ShowClasses;
MetaspaceReporter::print_report(out, scale, flags);
}
void MetaspaceUtils::print_on(outputStream* out) {
// Used from all GCs. It first prints out totals, then, separately, the class space portion.
out->print_cr(" Metaspace "
"used " SIZE_FORMAT "K, "
"committed " SIZE_FORMAT "K, "
"reserved " SIZE_FORMAT "K",
used_bytes()/K,
committed_bytes()/K,
reserved_bytes()/K);
if (Metaspace::using_class_space()) {
const Metaspace::MetadataType ct = Metaspace::ClassType;
out->print_cr(" class space "
"used " SIZE_FORMAT "K, "
"committed " SIZE_FORMAT "K, "
"reserved " SIZE_FORMAT "K",
used_bytes(ct)/K,
committed_bytes(ct)/K,
reserved_bytes(ct)/K);
}
}
#ifdef ASSERT
void MetaspaceUtils::verify() {
if (Metaspace::initialized()) {
// Verify non-class chunkmanager...
ChunkManager* cm = ChunkManager::chunkmanager_nonclass();
cm->verify();
// ... and space list.
VirtualSpaceList* vsl = VirtualSpaceList::vslist_nonclass();
vsl->verify();
if (Metaspace::using_class_space()) {
// If we use compressed class pointers, verify class chunkmanager...
cm = ChunkManager::chunkmanager_class();
cm->verify();
// ... and class spacelist.
vsl = VirtualSpaceList::vslist_class();
vsl->verify();
}
}
}
#endif
////////////////////////////////7
// MetaspaceGC methods
volatile size_t MetaspaceGC::_capacity_until_GC = 0;
uint MetaspaceGC::_shrink_factor = 0;
// 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 = Atomic::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::reserve_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(&_capacity_until_GC, old_capacity_until_GC, new_value);
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(&_capacity_until_GC, v);
}
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);
}
}
////// Metaspace methods /////
const MetaspaceTracer* Metaspace::_tracer = NULL;
DEBUG_ONLY(bool Metaspace::_frozen = false;)
bool Metaspace::initialized() {
return metaspace::MetaspaceContext::context_nonclass() != NULL
LP64_ONLY(&& (using_class_space() ? Metaspace::class_space_is_initialized() : true));
}
#ifdef _LP64
void Metaspace::print_compressed_class_space(outputStream* st) {
if (VirtualSpaceList::vslist_class() != NULL) {
MetaWord* base = VirtualSpaceList::vslist_class()->base_of_first_node();
size_t size = VirtualSpaceList::vslist_class()->word_size_of_first_node();
MetaWord* top = base + size;
st->print("Compressed class space mapped at: " PTR_FORMAT "-" PTR_FORMAT ", reserved size: " SIZE_FORMAT,
p2i(base), p2i(top), (top - base) * BytesPerWord);
st->cr();
}
}
// Given a prereserved space, use that to set up the compressed class space list.
void Metaspace::initialize_class_space(ReservedSpace rs) {
assert(rs.size() >= CompressedClassSpaceSize,
SIZE_FORMAT " != " SIZE_FORMAT, rs.size(), CompressedClassSpaceSize);
assert(using_class_space(), "Must be using class space");
assert(rs.size() == CompressedClassSpaceSize, SIZE_FORMAT " != " SIZE_FORMAT,
rs.size(), CompressedClassSpaceSize);
assert(is_aligned(rs.base(), Metaspace::reserve_alignment()) &&
is_aligned(rs.size(), Metaspace::reserve_alignment()),
"wrong alignment");
MetaspaceContext::initialize_class_space_context(rs);
// This does currently not work because rs may be the result of a split
// operation and NMT seems not to be able to handle splits.
// Will be fixed with JDK-8243535.
// MemTracker::record_virtual_memory_type((address)rs.base(), mtClass);
}
// Returns true if class space has been setup (initialize_class_space).
bool Metaspace::class_space_is_initialized() {
return MetaspaceContext::context_class() != NULL;
}
// Reserve a range of memory at an address suitable for en/decoding narrow
// Klass pointers (see: CompressedClassPointers::is_valid_base()).
// The returned address shall both be suitable as a compressed class pointers
// base, and aligned to Metaspace::reserve_alignment (which is equal to or a
// multiple of allocation granularity).
// On error, returns an unreserved space.
ReservedSpace Metaspace::reserve_address_space_for_compressed_classes(size_t size) {
#if defined(AARCH64) || defined(PPC64)
const size_t alignment = Metaspace::reserve_alignment();
// 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.
// Additionally, above 32G, ensure the lower LogKlassAlignmentInBytes bits
// of the upper 32-bits of the address are zero so we can handle a shift
// when decoding.
// PPC64: smaller heaps up to 2g will be mapped just below 4g. Then the
// attempt to place the compressed class space just after the heap fails on
// Linux 4.1.42 and higher because the launcher is loaded at 4g
// (ELF_ET_DYN_BASE). In that case we reach here and search the address space
// below 32g to get a zerobased CCS. For simplicity we reuse the search
// strategy for AARCH64.
static const struct {
address from;
address to;
size_t increment;
} search_ranges[] = {
{ (address)(4*G), (address)(32*G), 4*G, },
{ (address)(32*G), (address)(1024*G), (4 << LogKlassAlignmentInBytes) * G },
{ NULL, NULL, 0 }
};
for (int i = 0; search_ranges[i].from != NULL; i ++) {
address a = search_ranges[i].from;
assert(CompressedKlassPointers::is_valid_base(a), "Sanity");
while (a < search_ranges[i].to) {
ReservedSpace rs(size, Metaspace::reserve_alignment(),
false /*large_pages*/, (char*)a);
if (rs.is_reserved()) {
assert(a == (address)rs.base(), "Sanity");
return rs;
}
a += search_ranges[i].increment;
}
}
#endif // defined(AARCH64) || defined(PPC64)
#ifdef AARCH64
// Note: on AARCH64, if the code above does not find any good placement, we
// have no recourse. We return an empty space and the VM will exit.
return ReservedSpace();
#else
// Default implementation: Just reserve anywhere.
return ReservedSpace(size, Metaspace::reserve_alignment(), false, (char*)NULL);
#endif // AARCH64
}
#endif // _LP64
size_t Metaspace::reserve_alignment_words() {
return metaspace::Settings::virtual_space_node_reserve_alignment_words();
}
size_t Metaspace::commit_alignment_words() {
return metaspace::Settings::commit_granule_words();
}
void Metaspace::ergo_initialize() {
// Must happen before using any setting from Settings::---
metaspace::Settings::ergo_initialize();
// MaxMetaspaceSize and CompressedClassSpaceSize:
//
// MaxMetaspaceSize is the maximum size, in bytes, of memory we are allowed
// to commit for the Metaspace.
// It is just a number; a limit we compare against before committing. It
// does not have to be aligned to anything.
// It gets used as compare value before attempting to increase the metaspace
// commit charge. It defaults to max_uintx (unlimited).
//
// CompressedClassSpaceSize is the size, in bytes, of the address range we
// pre-reserve for the compressed class space (if we use class space).
// This size has to be aligned to the metaspace reserve alignment (to the
// size of a root chunk). It gets aligned up from whatever value the caller
// gave us to the next multiple of root chunk size.
//
// Note: Strictly speaking MaxMetaspaceSize and CompressedClassSpaceSize have
// very little to do with each other. The notion often encountered:
// MaxMetaspaceSize = CompressedClassSpaceSize + <non-class metadata size>
// is subtly wrong: MaxMetaspaceSize can besmaller than CompressedClassSpaceSize,
// in which case we just would not be able to fully commit the class space range.
//
// We still adjust CompressedClassSpaceSize to reasonable limits, mainly to
// save on reserved space, and to make ergnonomics less confusing.
MaxMetaspaceSize = MAX2(MaxMetaspaceSize, commit_alignment());
if (UseCompressedClassPointers) {
// Let CCS size not be larger than 80% of MaxMetaspaceSize. Note that is
// grossly over-dimensioned for most usage scenarios; typical ratio of
// class space : non class space usage is about 1:6. With many small classes,
// it can get as low as 1:2. It is not a big deal though since ccs is only
// reserved and will be committed on demand only.
size_t max_ccs_size = MaxMetaspaceSize * 0.8;
size_t adjusted_ccs_size = MIN2(CompressedClassSpaceSize, max_ccs_size);
// CCS must be aligned to root chunk size, and be at least the size of one
// root chunk.
adjusted_ccs_size = align_up(adjusted_ccs_size, reserve_alignment());
adjusted_ccs_size = MAX2(adjusted_ccs_size, reserve_alignment());
// Note: re-adjusting may have us left with a CompressedClassSpaceSize
// larger than MaxMetaspaceSize for very small values of MaxMetaspaceSize.
// Lets just live with that, its not a big deal.
if (adjusted_ccs_size != CompressedClassSpaceSize) {
FLAG_SET_ERGO(CompressedClassSpaceSize, adjusted_ccs_size);
log_info(metaspace)("Setting CompressedClassSpaceSize to " SIZE_FORMAT ".",
CompressedClassSpaceSize);
}
}
// Set MetaspaceSize, MinMetaspaceExpansion and MaxMetaspaceExpansion
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());
}
void Metaspace::global_initialize() {
MetaspaceGC::initialize(); // <- since we do not prealloc init chunks anymore is this still needed?
metaspace::ChunkHeaderPool::initialize();
if (DumpSharedSpaces) {
assert(!UseSharedSpaces, "sanity");
MetaspaceShared::initialize_for_static_dump();
}
// If UseCompressedClassPointers=1, we have two cases:
// a) if CDS is active (runtime, Xshare=on), it will create the class space
// for us, initialize it and set up CompressedKlassPointers encoding.
// Class space will be reserved above the mapped archives.
// b) if CDS either deactivated (Xshare=off) or a static dump is to be done (Xshare:dump),
// we will create the class space on our own. It will be placed above the java heap,
// since we assume it has been placed in low
// address regions. We may rethink this (see JDK-8244943). Failing that,
// it will be placed anywhere.
#if INCLUDE_CDS
// case (a)
if (UseSharedSpaces) {
MetaspaceShared::initialize_runtime_shared_and_meta_spaces();
// If any of the archived space fails to map, UseSharedSpaces
// is reset to false.
}
if (DynamicDumpSharedSpaces && !UseSharedSpaces) {
vm_exit_during_initialization("DynamicDumpSharedSpaces is unsupported when base CDS archive is not loaded", NULL);
}
#endif // INCLUDE_CDS
#ifdef _LP64
if (using_class_space() && !class_space_is_initialized()) {
assert(!UseSharedSpaces, "CDS archive is not mapped at this point");
// case (b)
ReservedSpace rs;
// If UseCompressedOops=1 and the java heap has been placed in coops-friendly
// territory, i.e. its base is under 32G, then we attempt to place ccs
// right above the java heap.
// Otherwise the lower 32G are still free. We try to place ccs at the lowest
// allowed mapping address.
address base = (UseCompressedOops && (uint64_t)CompressedOops::base() < OopEncodingHeapMax) ?
CompressedOops::end() : (address)HeapBaseMinAddress;
base = align_up(base, Metaspace::reserve_alignment());
const size_t size = align_up(CompressedClassSpaceSize, Metaspace::reserve_alignment());
if (base != NULL) {
if (CompressedKlassPointers::is_valid_base(base)) {
rs = ReservedSpace(size, Metaspace::reserve_alignment(),
false /* large */, (char*)base);
}
}
// ...failing that, reserve anywhere, but let platform do optimized placement:
if (!rs.is_reserved()) {
rs = Metaspace::reserve_address_space_for_compressed_classes(size);
}
// ...failing that, give up.
if (!rs.is_reserved()) {
vm_exit_during_initialization(
err_msg("Could not allocate compressed class space: " SIZE_FORMAT " bytes",
CompressedClassSpaceSize));
}
// Initialize space
Metaspace::initialize_class_space(rs);
// Set up compressed class pointer encoding.
CompressedKlassPointers::initialize((address)rs.base(), rs.size());
}
#endif
// Initialize non-class virtual space list, and its chunk manager:
MetaspaceContext::initialize_nonclass_space_context();
_tracer = new MetaspaceTracer();
// We must prevent the very first address of the ccs from being used to store
// metadata, since that address would translate to a narrow pointer of 0, and the
// VM does not distinguish between "narrow 0 as in NULL" and "narrow 0 as in start
// of ccs".
// Before Elastic Metaspace that did not happen due to the fact that every Metachunk
// had a header and therefore could not allocate anything at offset 0.
#ifdef _LP64
if (using_class_space()) {
// The simplest way to fix this is to allocate a tiny dummy chunk right at the
// start of ccs and do not use it for anything.
MetaspaceContext::context_class()->cm()->get_chunk(metaspace::chunklevel::HIGHEST_CHUNK_LEVEL);
}
#endif
#ifdef _LP64
if (UseCompressedClassPointers) {
// Note: "cds" would be a better fit but keep this for backward compatibility.
LogTarget(Info, gc, metaspace) lt;
if (lt.is_enabled()) {
ResourceMark rm;
LogStream ls(lt);
CDS_ONLY(MetaspaceShared::print_on(&ls);)
Metaspace::print_compressed_class_space(&ls);
CompressedKlassPointers::print_mode(&ls);
}
}
#endif
}
void Metaspace::post_initialize() {
MetaspaceGC::post_initialize();
}
size_t Metaspace::max_allocation_word_size() {
const size_t max_overhead_words = metaspace::get_raw_word_size_for_requested_word_size(1);
return metaspace::chunklevel::MAX_CHUNK_WORD_SIZE - max_overhead_words;
}
// This version of Metaspace::allocate does not throw OOM but simply returns NULL, and
// is suitable for calling from non-Java threads.
// Callers are responsible for checking null.
MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size,
MetaspaceObj::Type type) {
assert(word_size <= Metaspace::max_allocation_word_size(),
"allocation size too large (" SIZE_FORMAT ")", word_size);
assert(!_frozen, "sanity");
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) {
// Zero initialize.
Copy::fill_to_words((HeapWord*)result, word_size, 0);
log_trace(metaspace)("Metaspace::allocate: type %d return " PTR_FORMAT ".", (int)type, p2i(result));
}
return result;
}
MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size,
MetaspaceObj::Type type, TRAPS) {
assert(THREAD->is_Java_thread(), "can't allocate in non-Java thread because we cannot throw exception");
if (HAS_PENDING_EXCEPTION) {
assert(false, "Should not allocate with exception pending");
return NULL; // caller does a CHECK_NULL too
}
MetaWord* result = allocate(loader_data, word_size, type);
if (result == NULL) {
MetadataType mdtype = (type == MetaspaceObj::ClassType) ? ClassType : NonClassType;
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) {
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);
log_trace(metaspace)("Metaspace::allocate: type %d return " PTR_FORMAT ".", (int)type, p2i(result));
}
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);
}
// TODO: this exception text may be wrong and misleading. This needs more thinking. See JDK-8252189.
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) +
align_up(word_size * BytesPerWord, 4 * M) >
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() {
ChunkManager* cm = ChunkManager::chunkmanager_nonclass();
if (cm != NULL) {
cm->purge();
}
if (using_class_space()) {
cm = ChunkManager::chunkmanager_class();
if (cm != NULL) {
cm->purge();
}
}
}
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() && VirtualSpaceList::vslist_class()->contains((MetaWord*)ptr)) {
return true;
}
return VirtualSpaceList::vslist_nonclass()->contains((MetaWord*)ptr);
}
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