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 
  25 #include "precompiled.hpp"
  26 #include "jfr/leakprofiler/emitEventOperation.hpp"
  27 #include "jfr/leakprofiler/leakProfiler.hpp"
  28 #include "jfr/leakprofiler/startOperation.hpp"
  29 #include "jfr/leakprofiler/stopOperation.hpp"
  30 #include "jfr/leakprofiler/sampling/objectSampler.hpp"
  31 #include "jfr/recorder/service/jfrOptionSet.hpp"
  32 #include "memory/iterator.hpp"
  33 #include "oops/oop.hpp"
  34 #include "runtime/atomic.hpp"
  35 #include "runtime/orderAccess.hpp"
  36 #include "runtime/thread.inline.hpp"
  37 #include "runtime/vmThread.hpp"
  38 #include "utilities/ostream.hpp"
  39 
  40 // Only to be updated during safepoint
  41 ObjectSampler* LeakProfiler::_object_sampler = NULL;
  42 
  43 static volatile jbyte suspended = 0;
  44 bool LeakProfiler::start(jint sample_count) {
  45   if (UseZGC) {
  46     log_warning(jfr)("LeakProfiler is currently not supported in combination with ZGC");
  47     return false;
  48   }
  49 
  50   if (_object_sampler != NULL) {
  51     // already started
  52     return true;
  53   }
  54   // Allows user to disable leak profiler on command line by setting queue size to zero.
  55   if (sample_count > 0) {
  56     StartOperation op(sample_count);
  57     VMThread::execute(&op);
  58     return _object_sampler != NULL;
  59   }
  60   return false;
  61 }
  62 
  63 bool LeakProfiler::stop() {
  64   if (_object_sampler == NULL) {
  65     // already stopped/not started
  66     return true;
  67   }
  68   StopOperation op;
  69   VMThread::execute(&op);
  70   return _object_sampler == NULL;
  71 }
  72 
  73 void LeakProfiler::emit_events(jlong cutoff_ticks, bool emit_all) {
  74   if (!is_running()) {
  75     return;
  76   }
  77   EmitEventOperation op(cutoff_ticks, emit_all);
  78   VMThread::execute(&op);
  79 }
  80 
  81 void LeakProfiler::oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
  82   assert(SafepointSynchronize::is_at_safepoint(),
  83     "Leak Profiler::oops_do(...) may only be called during safepoint");
  84 
  85   if (_object_sampler != NULL) {
  86     _object_sampler->oops_do(is_alive, f);
  87   }
  88 }
  89 
  90 void LeakProfiler::sample(HeapWord* object,
  91                           size_t size,
  92                           JavaThread* thread) {
  93   assert(is_running(), "invariant");
  94   assert(thread != NULL, "invariant");
  95   assert(thread->thread_state() == _thread_in_vm, "invariant");
  96 
  97   // exclude compiler threads and code sweeper thread
  98   if (thread->is_hidden_from_external_view()) {
  99     return;
 100   }
 101 
 102   _object_sampler->add(object, size, thread);
 103 }
 104 
 105 ObjectSampler* LeakProfiler::object_sampler() {
 106   assert(is_suspended() || SafepointSynchronize::is_at_safepoint(),
 107     "Leak Profiler::object_sampler() may only be called during safepoint");
 108   return _object_sampler;
 109 }
 110 
 111 void LeakProfiler::set_object_sampler(ObjectSampler* object_sampler) {
 112   assert(SafepointSynchronize::is_at_safepoint(),
 113     "Leak Profiler::set_object_sampler() may only be called during safepoint");
 114   _object_sampler = object_sampler;
 115 }
 116 
 117 bool LeakProfiler::is_running() {
 118   return _object_sampler != NULL && !suspended;
 119 }
 120 
 121 bool LeakProfiler::is_suspended() {
 122   return _object_sampler != NULL && suspended;
 123 }
 124 
 125 void LeakProfiler::resume() {
 126   assert(is_suspended(), "invariant");
 127   OrderAccess::storestore();
 128   Atomic::store((jbyte)0, &suspended);
 129   assert(is_running(), "invariant");
 130 }
 131 
 132 void LeakProfiler::suspend() {
 133   assert(SafepointSynchronize::is_at_safepoint(), "invariant");
 134   assert(_object_sampler != NULL, "invariant");
 135   assert(!is_suspended(), "invariant");
 136   suspended = (jbyte)1; // safepoint visible
 137 }