/* * Copyright (c) 2011, 2022, Oracle and/or its affiliates. All rights reserved. * Copyright (c) 2017, 2021 SAP SE. 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. *
*/
using metaspace::ChunkManager; using metaspace::CommitLimiter; using metaspace::MetaspaceContext; using metaspace::MetaspaceReporter; using metaspace::RunningCounters; using metaspace::VirtualSpaceList;
// Retrieve all statistics in one go; make sure the values are consistent.
MetaspaceStats MetaspaceUtils::get_statistics(Metaspace::MetadataType mdtype) {
// Consistency: // This function reads three values (reserved, committed, used) from different counters. These counters // may (very rarely) be out of sync. This has been a source for intermittent test errors in the past // (see e.g. JDK-8237872, JDK-8151460). // - reserved and committed counter are updated under protection of Metaspace_lock; an inconsistency // between them can be the result of a dirty read. // - used is an atomic counter updated outside any lock range; there is no way to guarantee // a clean read wrt the other two values. // Reading these values under lock protection would would only help for the first case. Therefore // we don't bother and just re-read several times, then give up and correct the values.
size_t r = 0, c = 0, u = 0; // Note: byte values.
get_values_for(mdtype, &r, &c, &u); int retries = 10; // If the first retrieval resulted in inconsistent values, retry a bit... while ((r < c || c < u) && --retries >= 0) {
get_values_for(mdtype, &r, &c, &u);
} if (c < u || r < c) { // still inconsistent. // ... but not endlessly. If we don't get consistent values, correct them on the fly. // The logic here is that we trust the used counter - its an atomic counter and whatever we see // must have been the truth once - and from that we reconstruct a likely set of committed/reserved // values.
metaspace::InternalStats::inc_num_inconsistent_stats(); if (c < u) {
c = align_up(u, Metaspace::commit_alignment());
} if (r < c) {
r = align_up(c, Metaspace::reserve_alignment());
}
} return MetaspaceStats(r, c, u);
}
// 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.
// 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) { constint flags =
(int)MetaspaceReporter::Option::ShowLoaders |
(int)MetaspaceReporter::Option::BreakDownByChunkType |
(int)MetaspaceReporter::Option::ShowClasses;
MetaspaceReporter::print_report(out, scale, flags);
}
// Used from all GCs. It first prints out totals, then, separately, the class space portion.
MetaspaceCombinedStats stats = get_combined_statistics();
out->print_cr(" Metaspace " "used " SIZE_FORMAT "K, " "committed " SIZE_FORMAT "K, " "reserved " SIZE_FORMAT "K",
stats.used()/K,
stats.committed()/K,
stats.reserved()/K);
if (Metaspace::using_class_space()) {
out->print_cr(" class space " "used " SIZE_FORMAT "K, " "committed " SIZE_FORMAT "K, " "reserved " SIZE_FORMAT "K",
stats.class_space_stats().used()/K,
stats.class_space_stats().committed()/K,
stats.class_space_stats().reserved()/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();
}
// 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;
} elseif (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;
}
// 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());
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;
} returnfalse;
}
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)); returnfalse;
}
}
// 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)); returnfalse;
}
// 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();
// 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;
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;
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");
// 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) {
// 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.
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(),
os::vm_page_size(), (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(), os::vm_page_size(), (char*)NULL); #endif// AARCH64
}
// 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.
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;
}
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) { if (!FLAG_IS_DEFAULT(CompressedClassSpaceBaseAddress)) {
log_warning(metaspace)("CDS active - ignoring CompressedClassSpaceBaseAddress.");
}
MetaspaceShared::initialize_runtime_shared_and_meta_spaces(); // If any of the archived space fails to map, UseSharedSpaces // is reset to false.
} #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) (No CDS)
ReservedSpace rs; const size_t size = align_up(CompressedClassSpaceSize, Metaspace::reserve_alignment());
address base = NULL;
// If CompressedClassSpaceBaseAddress is set, we attempt to force-map class space to // the given address. This is a debug-only feature aiding tests. Due to the ASLR lottery // this may fail, in which case the VM will exit after printing an appropriate message. // Tests using this switch should cope with that. if (CompressedClassSpaceBaseAddress != 0) {
base = (address)CompressedClassSpaceBaseAddress; if (!is_aligned(base, Metaspace::reserve_alignment())) {
vm_exit_during_initialization(
err_msg("CompressedClassSpaceBaseAddress=" PTR_FORMAT " invalid " "(must be aligned to " SIZE_FORMAT_X ").",
CompressedClassSpaceBaseAddress, Metaspace::reserve_alignment()));
}
rs = ReservedSpace(size, Metaspace::reserve_alignment(),
os::vm_page_size() /* large */, (char*)base); if (rs.is_reserved()) {
log_info(metaspace)("Successfully forced class space address to " PTR_FORMAT, p2i(base));
} else {
vm_exit_during_initialization(
err_msg("CompressedClassSpaceBaseAddress=" PTR_FORMAT " given, but reserving class space failed.",
CompressedClassSpaceBaseAddress));
}
}
if (!rs.is_reserved()) { // 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.
base = (UseCompressedOops && (uint64_t)CompressedOops::base() < OopEncodingHeapMax) ?
CompressedOops::end() : (address)HeapBaseMinAddress;
base = align_up(base, Metaspace::reserve_alignment());
if (base != NULL) { if (CompressedKlassPointers::is_valid_base(base)) {
rs = ReservedSpace(size, Metaspace::reserve_alignment(),
os::vm_page_size(), (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
// 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(loader_data != NULL, "Should never pass around a NULL loader_data. " "ClassLoaderData::the_null_class_loader_data() should have been used.");
// Deal with concurrent unloading failed allocation starvation
MetaspaceCriticalAllocation::block_if_concurrent_purge();
// 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 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);
}
// -XX:+HeapDumpOnOutOfMemoryError and -XX:OnOutOfMemoryError support constchar* 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());
}
}
constchar* 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(bool classes_unloaded) { // The MetaspaceCritical_lock is used by a concurrent GC to block out concurrent metaspace // allocations, that would starve critical metaspace allocations, that are about to throw // OOM if they fail; they need precedence for correctness.
MutexLocker ml(MetaspaceCritical_lock, Mutex::_no_safepoint_check_flag); if (classes_unloaded) {
ChunkManager* cm = ChunkManager::chunkmanager_nonclass(); if (cm != NULL) {
cm->purge();
} if (using_class_space()) {
cm = ChunkManager::chunkmanager_class(); if (cm != NULL) {
cm->purge();
}
}
}
// Try to satisfy queued metaspace allocation requests. // // It might seem unnecessary to try to process allocation requests if no // classes have been unloaded. However, this call is required for the code // in MetaspaceCriticalAllocation::try_allocate_critical to work.
MetaspaceCriticalAllocation::process();
}
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