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/thread.inline.hpp"
  35 #include "runtime/vmThread.hpp"
  36 
  37 bool LeakProfiler::is_running() {
  38   return ObjectSampler::is_created();
  39 }
  40 
  41 bool LeakProfiler::start(int sample_count) {
  42   if (is_running()) {
  43     return true;
  44   }
  45 
  46   // Allows user to disable leak profiler on command line by setting queue size to zero.
  47   if (sample_count == 0) {
  48     return false;
  49   }
  50 
  51   if (UseZGC) {
  52     log_warning(jfr)("LeakProfiler is currently not supported in combination with ZGC");
  53     return false;
  54   }
  55 
  56   if (UseShenandoahGC) {
  57     log_warning(jfr)("LeakProfiler is currently not supported in combination with Shenandoah GC");
  58     return false;
  59   }
  60 
  61   assert(!is_running(), "invariant");
  62   assert(sample_count > 0, "invariant");
  63 
  64   // schedule the safepoint operation for installing the object sampler
  65   StartOperation op(sample_count);
  66   VMThread::execute(&op);
  67 
  68   if (!is_running()) {
  69     log_trace(jfr, system)("Object sampling could not be started because the sampler could not be allocated");
  70     return false;
  71   }
  72   assert(is_running(), "invariant");
  73   log_trace(jfr, system)("Object sampling started");
  74   return true;
  75 }
  76 
  77 bool LeakProfiler::stop() {
  78   if (!is_running()) {
  79     return false;
  80   }
  81 
  82   // schedule the safepoint operation for uninstalling and destroying the object sampler
  83   StopOperation op;
  84   VMThread::execute(&op);
  85 
  86   assert(!is_running(), "invariant");
  87   log_trace(jfr, system)("Object sampling stopped");
  88   return true;
  89 }
  90 
  91 void LeakProfiler::emit_events(int64_t cutoff_ticks, bool emit_all) {
  92   if (!is_running()) {
  93     return;
  94   }
  95   // exclusive access to object sampler instance
  96   ObjectSampler* const sampler = ObjectSampler::acquire();
  97   assert(sampler != NULL, "invariant");
  98   EventEmitter::emit(sampler, cutoff_ticks, emit_all);
  99   ObjectSampler::release();
 100 }
 101 
 102 void LeakProfiler::oops_do(BoolObjectClosure* is_alive, OopClosure* f) {
 103   assert(SafepointSynchronize::is_at_safepoint(),
 104     "Leak Profiler::oops_do(...) may only be called during safepoint");
 105   if (is_running()) {
 106     ObjectSampler::oops_do(is_alive, f);
 107   }
 108 }
 109 
 110 void LeakProfiler::sample(HeapWord* object, size_t size, JavaThread* thread) {
 111   assert(is_running(), "invariant");
 112   assert(thread != NULL, "invariant");
 113   assert(thread->thread_state() == _thread_in_vm, "invariant");
 114 
 115   // exclude compiler threads and code sweeper thread
 116   if (thread->is_hidden_from_external_view()) {
 117     return;
 118   }
 119 
 120   ObjectSampler::sample(object, size, thread);
 121 }