1 /*

     2  * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 #include "precompiled.hpp"

    25 #include "gc/shared/collectedHeap.hpp"

    26 #include "jfr/jfrEvents.hpp"

    27 #include "jfr/leakprofiler/utilities/granularTimer.hpp"

    28 #include "jfr/leakprofiler/chains/rootSetClosure.hpp"

    29 #include "jfr/leakprofiler/chains/edge.hpp"

    30 #include "jfr/leakprofiler/chains/edgeQueue.hpp"

    31 #include "jfr/leakprofiler/chains/edgeStore.hpp"

    32 #include "jfr/leakprofiler/chains/bitset.hpp"

    33 #include "jfr/leakprofiler/sampling/objectSample.hpp"

    34 #include "jfr/leakprofiler/leakProfiler.hpp"

    35 #include "jfr/leakprofiler/checkpoint/objectSampleCheckpoint.hpp"

    36 #include "jfr/leakprofiler/sampling/objectSampler.hpp"

    37 #include "jfr/leakprofiler/emitEventOperation.hpp"

    38 #include "jfr/leakprofiler/chains/bfsClosure.hpp"

    39 #include "jfr/leakprofiler/chains/dfsClosure.hpp"

    40 #include "jfr/leakprofiler/chains/objectSampleMarker.hpp"

    41 #include "jfr/recorder/checkpoint/jfrCheckpointWriter.hpp"

    42 #include "jfr/support/jfrThreadId.hpp"

    43 #include "logging/log.hpp"

    44 #include "memory/resourceArea.hpp"

    45 #include "memory/universe.hpp"

    46 #include "oops/markOop.hpp"

    47 #include "oops/oop.inline.hpp"

    48 #include "runtime/safepoint.hpp"

    49 #include "runtime/vmThread.hpp"

    50 #include "utilities/globalDefinitions.hpp"

    51 

    52 /* The EdgeQueue is backed by directly managed virtual memory.

    53  * We will attempt to dimension an initial reservation

    54  * in proportion to the size of the heap (represented by heap_region).

    55  * Initial memory reservation: 5% of the heap OR at least 32 Mb

    56  * Commit ratio: 1 : 10 (subject to allocation granularties)

    57  */

    58 static size_t edge_queue_memory_reservation(const MemRegion& heap_region) {

    59   const size_t memory_reservation_bytes = MAX2(heap_region.byte_size() / 20, 32*M);

    60   assert(memory_reservation_bytes >= (size_t)32*M, "invariant");

    61   return memory_reservation_bytes;

    62 }

    63 

    64 static size_t edge_queue_memory_commit_size(size_t memory_reservation_bytes) {

    65   const size_t memory_commit_block_size_bytes = memory_reservation_bytes / 10;

    66   assert(memory_commit_block_size_bytes >= (size_t)3*M, "invariant");

    67   return memory_commit_block_size_bytes;

    68 }

    69 

    70 static void log_edge_queue_summary(const EdgeQueue& edge_queue) {

    71   log_trace(jfr, system)("EdgeQueue reserved size total: " SIZE_FORMAT " [KB]", edge_queue.reserved_size() / K);

    72   log_trace(jfr, system)("EdgeQueue edges total: " SIZE_FORMAT, edge_queue.top());

    73   log_trace(jfr, system)("EdgeQueue liveset total: " SIZE_FORMAT " [KB]", edge_queue.live_set() / K);

    74   if (edge_queue.reserved_size() > 0) {

    75     log_trace(jfr, system)("EdgeQueue commit reserve ratio: %f\n",

    76       ((double)edge_queue.live_set() / (double)edge_queue.reserved_size()));

    77   }

    78 }

    79 

    80 void EmitEventOperation::doit() {

    81   assert(LeakProfiler::is_running(), "invariant");

    82   _object_sampler = LeakProfiler::object_sampler();

    83   assert(_object_sampler != NULL, "invariant");

    84 

    85   _vm_thread = VMThread::vm_thread();

    86   assert(_vm_thread == Thread::current(), "invariant");

    87   _vm_thread_local = _vm_thread->jfr_thread_local();

    88   assert(_vm_thread_local != NULL, "invariant");

    89   assert(_vm_thread->jfr_thread_local()->thread_id() == JFR_THREAD_ID(_vm_thread), "invariant");

    90 

    91   // The VM_Operation::evaluate() which invoked doit()

    92   // contains a top level ResourceMark

    93 

    94   // save the original markWord for the potential leak objects

    95   // to be restored on function exit

    96   ObjectSampleMarker marker;

    97   if (ObjectSampleCheckpoint::mark(marker, _emit_all) == 0) {

    98     return;

    99   }

   100 

   101   EdgeStore edge_store;

   102 

   103   GranularTimer::start(_cutoff_ticks, 1000000);

   104   if (_cutoff_ticks <= 0) {

   105     // no chains

   106     write_events(&edge_store);

   107     return;

   108   }

   109 

   110   assert(_cutoff_ticks > 0, "invariant");

   111 

   112   // The bitset used for marking is dimensioned as a function of the heap size

   113   const MemRegion heap_region = Universe::heap()->reserved_region();

   114   BitSet mark_bits(heap_region);

   115 

   116   // The edge queue is dimensioned as a fraction of the heap size

   117   const size_t edge_queue_reservation_size = edge_queue_memory_reservation(heap_region);

   118   EdgeQueue edge_queue(edge_queue_reservation_size, edge_queue_memory_commit_size(edge_queue_reservation_size));

   119 

   120   // The initialize() routines will attempt to reserve and allocate backing storage memory.

   121   // Failure to accommodate will render root chain processing impossible.

   122   // As a fallback on failure, just write out the existing samples, flat, without chains.

   123   if (!(mark_bits.initialize() && edge_queue.initialize())) {

   124     log_warning(jfr)("Unable to allocate memory for root chain processing");

   125     write_events(&edge_store);

   126     return;

   127   }

   128 

   129   // necessary condition for attempting a root set iteration

   130   Universe::heap()->ensure_parsability(false);

   131 

   132   RootSetClosure::add_to_queue(&edge_queue);

   133   if (edge_queue.is_full()) {

   134     // Pathological case where roots don't fit in queue

   135     // Do a depth-first search, but mark roots first

   136     // to avoid walking sideways over roots

   137     DFSClosure::find_leaks_from_root_set(&edge_store, &mark_bits);

   138   } else {

   139     BFSClosure bfs(&edge_queue, &edge_store, &mark_bits);

   140     bfs.process();

   141   }

   142   GranularTimer::stop();

   143   write_events(&edge_store);

   144   log_edge_queue_summary(edge_queue);

   145 }

   146 

   147 int EmitEventOperation::write_events(EdgeStore* edge_store) {

   148   assert(_object_sampler != NULL, "invariant");

   149   assert(edge_store != NULL, "invariant");

   150   assert(_vm_thread != NULL, "invariant");

   151   assert(_vm_thread_local != NULL, "invariant");

   152   assert(SafepointSynchronize::is_at_safepoint(), "invariant");

   153 

   154   // save thread id in preparation for thread local trace data manipulations

   155   const traceid vmthread_id = _vm_thread_local->thread_id();

   156   assert(_vm_thread_local->thread_id() == JFR_THREAD_ID(_vm_thread), "invariant");

   157 

   158   const jlong last_sweep = _emit_all ? max_jlong : _object_sampler->last_sweep().value();

   159   int count = 0;

   160 

   161   const ObjectSample* current = _object_sampler->first();

   162   while (current != NULL) {

   163     ObjectSample* prev = current->prev();

   164     if (current->is_alive_and_older_than(last_sweep)) {

   165       write_event(current, edge_store);

   166       ++count;

   167     }

   168     current = prev;

   169   }

   170 

   171   // restore thread local stack trace and thread id

   172   _vm_thread_local->set_thread_id(vmthread_id);

   173   _vm_thread_local->clear_cached_stack_trace();

   174   assert(_vm_thread_local->thread_id() == JFR_THREAD_ID(_vm_thread), "invariant");

   175 

   176   if (count > 0) {

   177     // serialize assoicated checkpoints

   178     ObjectSampleCheckpoint::write(edge_store, _emit_all, _vm_thread);

   179   }

   180   return count;

   181 }

   182 

   183 static int array_size(const oop object) {

   184   assert(object != NULL, "invariant");

   185   if (object->is_array()) {

   186     return arrayOop(object)->length();

   187   }

   188   return min_jint;

   189 }

   190 

   191 void EmitEventOperation::write_event(const ObjectSample* sample, EdgeStore* edge_store) {

   192   assert(sample != NULL, "invariant");

   193   assert(!sample->is_dead(), "invariant");

   194   assert(edge_store != NULL, "invariant");

   195   assert(_vm_thread_local != NULL, "invariant");

   196   const oop* object_addr = sample->object_addr();

   197   assert(*object_addr != NULL, "invariant");

   198 

   199   const Edge* edge = (const Edge*)(*object_addr)->mark();

   200   traceid gc_root_id = 0;

   201   if (edge == NULL) {

   202     // In order to dump out a representation of the event

   203     // even though it was not reachable / too long to reach,

   204     // we need to register a top level edge for this object

   205     Edge e(NULL, object_addr);

   206     edge_store->add_chain(&e, 1);

   207     edge = (const Edge*)(*object_addr)->mark();

   208   } else {

   209     gc_root_id = edge_store->get_root_id(edge);

   210   }

   211 

   212   assert(edge != NULL, "invariant");

   213   assert(edge->pointee() == *object_addr, "invariant");

   214   const traceid object_id = edge_store->get_id(edge);

   215   assert(object_id != 0, "invariant");

   216 

   217   EventOldObjectSample e(UNTIMED);

   218   e.set_starttime(GranularTimer::start_time());

   219   e.set_endtime(GranularTimer::end_time());

   220   e.set_allocationTime(sample->allocation_time());

   221   e.set_lastKnownHeapUsage(sample->heap_used_at_last_gc());

   222   e.set_object(object_id);

   223   e.set_arrayElements(array_size(*object_addr));

   224   e.set_root(gc_root_id);

   225 

   226   // Temporarily assigning both the stack trace id and thread id

   227   // onto the thread local data structure of the VMThread (for the duration

   228   // of the commit() call). This trick provides a means to override

   229   // the event generation mechanism by injecting externally provided id's.

   230   // Here, in particular, this allows us to emit an old object event

   231   // supplying information from where the actual sampling occurred.

   232   _vm_thread_local->set_cached_stack_trace_id(sample->stack_trace_id());

   233   assert(sample->has_thread(), "invariant");

   234   _vm_thread_local->set_thread_id(sample->thread_id());

   235   e.commit();

   236 }