1 /*
   2  * Copyright (c) 2014, 2019, 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/leakProfiler.hpp"
  27 #include "jfr/leakprofiler/startOperation.hpp"
  28 #include "jfr/leakprofiler/stopOperation.hpp"
  29 #include "jfr/leakprofiler/checkpoint/eventEmitter.hpp"
  30 #include "jfr/leakprofiler/sampling/objectSampler.hpp"
  31 #include "jfr/recorder/service/jfrOptionSet.hpp"
  32 #include "logging/log.hpp"
  33 #include "memory/iterator.hpp"
  34 #include "runtime/mutexLocker.hpp"
  35 #include "runtime/thread.inline.hpp"
  36 #include "runtime/vmThread.hpp"
  37 
  38 bool LeakProfiler::is_running() {
  39   return ObjectSampler::is_created();
  40 }
  41 
  42 bool LeakProfiler::start(int sample_count) {
  43   if (is_running()) {
  44     return true;
  45   }
  46 
  47   // Allows user to disable leak profiler on command line by setting queue size to zero.
  48   if (sample_count == 0) {
  49     return false;
  50   }
  51 
  52   assert(!is_running(), "invariant");
  53   assert(sample_count > 0, "invariant");
  54 
  55   // schedule the safepoint operation for installing the object sampler
  56   StartOperation op(sample_count);
  57   VMThread::execute(&op);
  58 
  59   if (!is_running()) {
  60     log_trace(jfr, system)("Object sampling could not be started because the sampler could not be allocated");
  61     return false;
  62   }
  63   assert(is_running(), "invariant");
  64   log_trace(jfr, system)("Object sampling started");
  65   return true;
  66 }
  67 
  68 bool LeakProfiler::stop() {
  69   if (!is_running()) {
  70     return false;
  71   }
  72 
  73   // schedule the safepoint operation for uninstalling and destroying the object sampler
  74   StopOperation op;
  75   VMThread::execute(&op);
  76 
  77   assert(!is_running(), "invariant");
  78   log_trace(jfr, system)("Object sampling stopped");
  79   return true;
  80 }
  81 
  82 void LeakProfiler::emit_events(int64_t cutoff_ticks, bool emit_all) {
  83   if (!is_running()) {
  84     return;
  85   }
  86   MutexLocker lock(JfrStream_lock);
  87   // exclusive access to object sampler instance
  88   ObjectSampler* const sampler = ObjectSampler::acquire();
  89   assert(sampler != NULL, "invariant");
  90   EventEmitter::emit(sampler, cutoff_ticks, emit_all);
  91   ObjectSampler::release();
  92 }
  93 
  94 void LeakProfiler::weak_oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
  95   assert(SafepointSynchronize::is_at_safepoint(),
  96     "Leak Profiler::oops_do(...) may only be called during safepoint");
  97   if (is_running()) {
  98     ObjectSampler::weak_oops_do(is_alive, f);
  99   }
 100 }
 101 
 102 void LeakProfiler::sample(HeapWord* object, size_t size, JavaThread* thread) {
 103   assert(is_running(), "invariant");
 104   assert(thread != NULL, "invariant");
 105   assert(thread->thread_state() == _thread_in_vm, "invariant");
 106 
 107   // exclude compiler threads and code sweeper thread
 108   if (thread->is_hidden_from_external_view()) {
 109     return;
 110   }
 111 
 112   ObjectSampler::sample(object, size, thread);
 113 }