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 (UseShenandoahGC) {
  51     log_warning(jfr)("LeakProfiler is currently not supported in combination with Shenandoah GC");
  52     return false;
  53   }
  54 
  55   if (_object_sampler != NULL) {
  56     // already started
  57     return true;
  58   }
  59   // Allows user to disable leak profiler on command line by setting queue size to zero.
  60   if (sample_count > 0) {
  61     StartOperation op(sample_count);
  62     VMThread::execute(&op);
  63     return _object_sampler != NULL;
  64   }
  65   return false;
  66 }
  67 
  68 bool LeakProfiler::stop() {
  69   if (_object_sampler == NULL) {
  70     // already stopped/not started
  71     return true;
  72   }
  73   StopOperation op;
  74   VMThread::execute(&op);
  75   return _object_sampler == NULL;
  76 }
  77 
  78 void LeakProfiler::emit_events(jlong cutoff_ticks, bool emit_all) {
  79   if (!is_running()) {
  80     return;
  81   }
  82   EmitEventOperation op(cutoff_ticks, emit_all);
  83   VMThread::execute(&op);
  84 }
  85 
  86 void LeakProfiler::oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
  87   assert(SafepointSynchronize::is_at_safepoint(),
  88     "Leak Profiler::oops_do(...) may only be called during safepoint");
  89 
  90   if (_object_sampler != NULL) {
  91     _object_sampler->oops_do(is_alive, f);
  92   }
  93 }
  94 
  95 void LeakProfiler::sample(HeapWord* object,
  96                           size_t size,
  97                           JavaThread* thread) {
  98   assert(is_running(), "invariant");
  99   assert(thread != NULL, "invariant");
 100   assert(thread->thread_state() == _thread_in_vm, "invariant");
 101 
 102   // exclude compiler threads and code sweeper thread
 103   if (thread->is_hidden_from_external_view()) {
 104     return;
 105   }
 106 
 107   _object_sampler->add(object, size, thread);
 108 }
 109 
 110 ObjectSampler* LeakProfiler::object_sampler() {
 111   assert(is_suspended() || SafepointSynchronize::is_at_safepoint(),
 112     "Leak Profiler::object_sampler() may only be called during safepoint");
 113   return _object_sampler;
 114 }
 115 
 116 void LeakProfiler::set_object_sampler(ObjectSampler* object_sampler) {
 117   assert(SafepointSynchronize::is_at_safepoint(),
 118     "Leak Profiler::set_object_sampler() may only be called during safepoint");
 119   _object_sampler = object_sampler;
 120 }
 121 
 122 bool LeakProfiler::is_running() {
 123   return _object_sampler != NULL && !suspended;
 124 }
 125 
 126 bool LeakProfiler::is_suspended() {
 127   return _object_sampler != NULL && suspended;
 128 }
 129 
 130 void LeakProfiler::resume() {
 131   assert(is_suspended(), "invariant");
 132   OrderAccess::storestore();
 133   Atomic::store((jbyte)0, &suspended);
 134   assert(is_running(), "invariant");
 135 }
 136 
 137 void LeakProfiler::suspend() {
 138   assert(SafepointSynchronize::is_at_safepoint(), "invariant");
 139   assert(_object_sampler != NULL, "invariant");
 140   assert(!is_suspended(), "invariant");
 141   suspended = (jbyte)1; // safepoint visible
 142 }