--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/services/memTracker.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,314 @@
+/*
+ * Copyright (c) 2012, 2017, 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 "prims/jvm.h"
+#include "runtime/mutex.hpp"
+#include "services/memBaseline.hpp"
+#include "services/memReporter.hpp"
+#include "services/mallocTracker.inline.hpp"
+#include "services/memTracker.hpp"
+#include "utilities/defaultStream.hpp"
+
+#ifdef SOLARIS
+ volatile bool NMT_stack_walkable = false;
+#else
+ volatile bool NMT_stack_walkable = true;
+#endif
+
+volatile NMT_TrackingLevel MemTracker::_tracking_level = NMT_unknown;
+NMT_TrackingLevel MemTracker::_cmdline_tracking_level = NMT_unknown;
+
+MemBaseline MemTracker::_baseline;
+Mutex* MemTracker::_query_lock = NULL;
+bool MemTracker::_is_nmt_env_valid = true;
+
+
+NMT_TrackingLevel MemTracker::init_tracking_level() {
+ NMT_TrackingLevel level = NMT_off;
+ char buf[64];
+ jio_snprintf(buf, sizeof(buf), "NMT_LEVEL_%d", os::current_process_id());
+ const char *nmt_option = ::getenv(buf);
+ if (nmt_option != NULL) {
+ if (strcmp(nmt_option, "summary") == 0) {
+ level = NMT_summary;
+ } else if (strcmp(nmt_option, "detail") == 0) {
+ level = NMT_detail;
+ } else if (strcmp(nmt_option, "off") != 0) {
+ // The option value is invalid
+ _is_nmt_env_valid = false;
+ }
+
+ // Remove the environment variable to avoid leaking to child processes
+ os::unsetenv(buf);
+ }
+
+ // Construct NativeCallStack::EMPTY_STACK. It may get constructed twice,
+ // but it is benign, the results are the same.
+ ::new ((void*)&NativeCallStack::EMPTY_STACK) NativeCallStack(0, false);
+
+ if (!MallocTracker::initialize(level) ||
+ !VirtualMemoryTracker::initialize(level)) {
+ level = NMT_off;
+ }
+ return level;
+}
+
+void MemTracker::init() {
+ NMT_TrackingLevel level = tracking_level();
+ if (level >= NMT_summary) {
+ if (!VirtualMemoryTracker::late_initialize(level)) {
+ shutdown();
+ return;
+ }
+ _query_lock = new (std::nothrow) Mutex(Monitor::max_nonleaf, "NMT_queryLock");
+ // Already OOM. It is unlikely, but still have to handle it.
+ if (_query_lock == NULL) {
+ shutdown();
+ }
+ }
+}
+
+bool MemTracker::check_launcher_nmt_support(const char* value) {
+ if (strcmp(value, "=detail") == 0) {
+ if (MemTracker::tracking_level() != NMT_detail) {
+ return false;
+ }
+ } else if (strcmp(value, "=summary") == 0) {
+ if (MemTracker::tracking_level() != NMT_summary) {
+ return false;
+ }
+ } else if (strcmp(value, "=off") == 0) {
+ if (MemTracker::tracking_level() != NMT_off) {
+ return false;
+ }
+ } else {
+ _is_nmt_env_valid = false;
+ }
+
+ return true;
+}
+
+bool MemTracker::verify_nmt_option() {
+ return _is_nmt_env_valid;
+}
+
+void* MemTracker::malloc_base(void* memblock) {
+ return MallocTracker::get_base(memblock);
+}
+
+void Tracker::record(address addr, size_t size) {
+ if (MemTracker::tracking_level() < NMT_summary) return;
+ switch(_type) {
+ case uncommit:
+ VirtualMemoryTracker::remove_uncommitted_region(addr, size);
+ break;
+ case release:
+ VirtualMemoryTracker::remove_released_region(addr, size);
+ break;
+ default:
+ ShouldNotReachHere();
+ }
+}
+
+
+// Shutdown can only be issued via JCmd, and NMT JCmd is serialized by lock
+void MemTracker::shutdown() {
+ // We can only shutdown NMT to minimal tracking level if it is ever on.
+ if (tracking_level () > NMT_minimal) {
+ transition_to(NMT_minimal);
+ }
+}
+
+bool MemTracker::transition_to(NMT_TrackingLevel level) {
+ NMT_TrackingLevel current_level = tracking_level();
+
+ assert(level != NMT_off || current_level == NMT_off, "Cannot transition NMT to off");
+
+ if (current_level == level) {
+ return true;
+ } else if (current_level > level) {
+ // Downgrade tracking level, we want to lower the tracking level first
+ _tracking_level = level;
+ // Make _tracking_level visible immediately.
+ OrderAccess::fence();
+ VirtualMemoryTracker::transition(current_level, level);
+ MallocTracker::transition(current_level, level);
+ } else {
+ // Upgrading tracking level is not supported and has never been supported.
+ // Allocating and deallocating malloc tracking structures is not thread safe and
+ // leads to inconsistencies unless a lot coarser locks are added.
+ }
+ return true;
+}
+
+void MemTracker::report(bool summary_only, outputStream* output) {
+ assert(output != NULL, "No output stream");
+ MemBaseline baseline;
+ if (baseline.baseline(summary_only)) {
+ if (summary_only) {
+ MemSummaryReporter rpt(baseline, output);
+ rpt.report();
+ } else {
+ MemDetailReporter rpt(baseline, output);
+ rpt.report();
+ }
+ }
+}
+
+// This is a walker to gather malloc site hashtable statistics,
+// the result is used for tuning.
+class StatisticsWalker : public MallocSiteWalker {
+ private:
+ enum Threshold {
+ // aggregates statistics over this threshold into one
+ // line item.
+ report_threshold = 20
+ };
+
+ private:
+ // Number of allocation sites that have all memory freed
+ int _empty_entries;
+ // Total number of allocation sites, include empty sites
+ int _total_entries;
+ // Number of captured call stack distribution
+ int _stack_depth_distribution[NMT_TrackingStackDepth];
+ // Hash distribution
+ int _hash_distribution[report_threshold];
+ // Number of hash buckets that have entries over the threshold
+ int _bucket_over_threshold;
+
+ // The hash bucket that walker is currently walking
+ int _current_hash_bucket;
+ // The length of current hash bucket
+ int _current_bucket_length;
+ // Number of hash buckets that are not empty
+ int _used_buckets;
+ // Longest hash bucket length
+ int _longest_bucket_length;
+
+ public:
+ StatisticsWalker() : _empty_entries(0), _total_entries(0) {
+ int index = 0;
+ for (index = 0; index < NMT_TrackingStackDepth; index ++) {
+ _stack_depth_distribution[index] = 0;
+ }
+ for (index = 0; index < report_threshold; index ++) {
+ _hash_distribution[index] = 0;
+ }
+ _bucket_over_threshold = 0;
+ _longest_bucket_length = 0;
+ _current_hash_bucket = -1;
+ _current_bucket_length = 0;
+ _used_buckets = 0;
+ }
+
+ virtual bool do_malloc_site(const MallocSite* e) {
+ if (e->size() == 0) _empty_entries ++;
+ _total_entries ++;
+
+ // stack depth distrubution
+ int frames = e->call_stack()->frames();
+ _stack_depth_distribution[frames - 1] ++;
+
+ // hash distribution
+ int hash_bucket = e->hash() % MallocSiteTable::hash_buckets();
+ if (_current_hash_bucket == -1) {
+ _current_hash_bucket = hash_bucket;
+ _current_bucket_length = 1;
+ } else if (_current_hash_bucket == hash_bucket) {
+ _current_bucket_length ++;
+ } else {
+ record_bucket_length(_current_bucket_length);
+ _current_hash_bucket = hash_bucket;
+ _current_bucket_length = 1;
+ }
+ return true;
+ }
+
+ // walk completed
+ void completed() {
+ record_bucket_length(_current_bucket_length);
+ }
+
+ void report_statistics(outputStream* out) {
+ int index;
+ out->print_cr("Malloc allocation site table:");
+ out->print_cr("\tTotal entries: %d", _total_entries);
+ out->print_cr("\tEmpty entries: %d (%2.2f%%)", _empty_entries, ((float)_empty_entries * 100) / _total_entries);
+ out->print_cr(" ");
+ out->print_cr("Hash distribution:");
+ if (_used_buckets < MallocSiteTable::hash_buckets()) {
+ out->print_cr("empty bucket: %d", (MallocSiteTable::hash_buckets() - _used_buckets));
+ }
+ for (index = 0; index < report_threshold; index ++) {
+ if (_hash_distribution[index] != 0) {
+ if (index == 0) {
+ out->print_cr(" %d entry: %d", 1, _hash_distribution[0]);
+ } else if (index < 9) { // single digit
+ out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
+ } else {
+ out->print_cr(" %d entries: %d", (index + 1), _hash_distribution[index]);
+ }
+ }
+ }
+ if (_bucket_over_threshold > 0) {
+ out->print_cr(" >%d entries: %d", report_threshold, _bucket_over_threshold);
+ }
+ out->print_cr("most entries: %d", _longest_bucket_length);
+ out->print_cr(" ");
+ out->print_cr("Call stack depth distribution:");
+ for (index = 0; index < NMT_TrackingStackDepth; index ++) {
+ if (_stack_depth_distribution[index] > 0) {
+ out->print_cr("\t%d: %d", index + 1, _stack_depth_distribution[index]);
+ }
+ }
+ }
+
+ private:
+ void record_bucket_length(int length) {
+ _used_buckets ++;
+ if (length <= report_threshold) {
+ _hash_distribution[length - 1] ++;
+ } else {
+ _bucket_over_threshold ++;
+ }
+ _longest_bucket_length = MAX2(_longest_bucket_length, length);
+ }
+};
+
+
+void MemTracker::tuning_statistics(outputStream* out) {
+ // NMT statistics
+ StatisticsWalker walker;
+ MallocSiteTable::walk_malloc_site(&walker);
+ walker.completed();
+
+ out->print_cr("Native Memory Tracking Statistics:");
+ out->print_cr("Malloc allocation site table size: %d", MallocSiteTable::hash_buckets());
+ out->print_cr(" Tracking stack depth: %d", NMT_TrackingStackDepth);
+ NOT_PRODUCT(out->print_cr("Peak concurrent access: %d", MallocSiteTable::access_peak_count());)
+ out->print_cr(" ");
+ walker.report_statistics(out);
+}