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 /*

  * Copyright (c) 2014, 2018, 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 "gc_interface/collectedHeap.hpp"

 #include "jfr/jfrEvents.hpp"

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

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

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

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

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

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

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

 #include "jfr/leakprofiler/leakProfiler.hpp"

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

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

 #include "jfr/leakprofiler/emitEventOperation.hpp"

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

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

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

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

 #include "jfr/support/jfrThreadId.hpp"

 #include "memory/resourceArea.hpp"

 #include "memory/universe.hpp"

 #include "oops/markOop.hpp"

 #include "oops/oop.inline.hpp"

 #include "runtime/safepoint.hpp"

 #include "runtime/vmThread.hpp"

 #include "utilities/globalDefinitions.hpp"

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

  * We will attempt to dimension an initial reservation

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

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

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

  */

 static size_t edge_queue_memory_reservation(const MemRegion& heap_region) {

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

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

   return memory_reservation_bytes;

 }

 static size_t edge_queue_memory_commit_size(size_t memory_reservation_bytes) {

   const size_t memory_commit_block_size_bytes = memory_reservation_bytes / 10;

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

   return memory_commit_block_size_bytes;

 }

 static void log_edge_queue_summary(const EdgeQueue& edge_queue) {

   if (LogJFR && Verbose) tty->print_cr("EdgeQueue reserved size total: " SIZE_FORMAT " [KB]", edge_queue.reserved_size() / K);

   if (LogJFR && Verbose) tty->print_cr("EdgeQueue edges total: " SIZE_FORMAT, edge_queue.top());

   if (LogJFR && Verbose) tty->print_cr("EdgeQueue liveset total: " SIZE_FORMAT " [KB]", edge_queue.live_set() / K);

   if (edge_queue.reserved_size() > 0) {

     if (LogJFR && Verbose) tty->print_cr("EdgeQueue commit reserve ratio: %f\n",

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

   }

 }

 void EmitEventOperation::doit() {

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

   _object_sampler = LeakProfiler::object_sampler();

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

   _vm_thread = VMThread::vm_thread();

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

   _vm_thread_local = _vm_thread->jfr_thread_local();

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

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

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

   // contains a top level ResourceMark

   // save the original markWord for the potential leak objects

   // to be restored on function exit

   ObjectSampleMarker marker;

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

     return;

   }

   EdgeStore edge_store;

   GranularTimer::start(_cutoff_ticks, 1000000);

   if (_cutoff_ticks <= 0) {

     // no chains

     write_events(&edge_store);

     return;

   }

   assert(_cutoff_ticks > 0, "invariant");

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

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

   BitSet mark_bits(heap_region);

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

   const size_t edge_queue_reservation_size = edge_queue_memory_reservation(heap_region);

   EdgeQueue edge_queue(edge_queue_reservation_size, edge_queue_memory_commit_size(edge_queue_reservation_size));

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

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

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

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

     if (LogJFR) tty->print_cr("Unable to allocate memory for root chain processing");

     write_events(&edge_store);

     return;

   }

   // necessary condition for attempting a root set iteration

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

   RootSetClosure::add_to_queue(&edge_queue);

   if (edge_queue.is_full()) {

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

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

     // to avoid walking sideways over roots

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

   } else {

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

     bfs.process();

   }

   GranularTimer::stop();

   write_events(&edge_store);

   log_edge_queue_summary(edge_queue);

 }

 int EmitEventOperation::write_events(EdgeStore* edge_store) {

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

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

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

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

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

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

   const traceid vmthread_id = _vm_thread_local->thread_id();

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

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

   int count = 0;

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

   while (current != NULL) {

     ObjectSample* prev = current->prev();

     if (current->is_alive_and_older_than(last_sweep)) {

       write_event(current, edge_store);

       ++count;

     }

     current = prev;

   }

   // restore thread local stack trace and thread id

   _vm_thread_local->set_thread_id(vmthread_id);

   _vm_thread_local->clear_cached_stack_trace();

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

   if (count > 0) {

     // serialize assoicated checkpoints

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

   }

   return count;

 }

 static int array_size(const oop object) {

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

   if (object->is_array()) {

     return arrayOop(object)->length();

   }

   return min_jint;

 }

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

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

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

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

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

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

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

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

   traceid gc_root_id = 0;

   if (edge == NULL) {

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

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

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

     Edge e(NULL, object_addr);

     edge_store->add_chain(&e, 1);

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

   } else {

     gc_root_id = edge_store->get_root_id(edge);

   }

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

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

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

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

   EventOldObjectSample e(UNTIMED);

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

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

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

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

   e.set_object(object_id);

   e.set_arrayElements(array_size(*object_addr));

   e.set_root(gc_root_id);

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

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

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

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

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

   // supplying information from where the actual sampling occurred.

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

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

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

   e.commit();

 }