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/chains/dfsClosure.hpp"

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

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

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

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

    31 #include "jfr/leakprofiler/utilities/unifiedOop.hpp"

    32 #include "jfr/leakprofiler/utilities/rootType.hpp"

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

    34 #include "memory/resourceArea.hpp"

    35 #include "oops/access.inline.hpp"

    36 #include "oops/oop.inline.hpp"

    37 #include "utilities/align.hpp"

    38 

    39 // max dfs depth should not exceed size of stack

    40 static const size_t max_dfs_depth = 5000;

    41 

    42 EdgeStore* DFSClosure::_edge_store = NULL;

    43 BitSet* DFSClosure::_mark_bits = NULL;

    44 const Edge* DFSClosure::_start_edge = NULL;

    45 size_t DFSClosure::_max_depth = max_dfs_depth;

    46 bool DFSClosure::_ignore_root_set = false;

    47 

    48 DFSClosure::DFSClosure() :

    49   _parent(NULL),

    50   _reference(NULL),

    51   _depth(0) {

    52 }

    53 

    54 DFSClosure::DFSClosure(DFSClosure* parent, size_t depth) :

    55   _parent(parent),

    56   _reference(NULL),

    57   _depth(depth) {

    58 }

    59 

    60 void DFSClosure::find_leaks_from_edge(EdgeStore* edge_store,

    61                                       BitSet* mark_bits,

    62                                       const Edge* start_edge) {

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

    64   assert(mark_bits != NULL," invariant");

    65   assert(start_edge != NULL, "invariant");

    66 

    67   _edge_store = edge_store;

    68   _mark_bits = mark_bits;

    69   _start_edge = start_edge;

    70   _ignore_root_set = false;

    71   assert(_max_depth == max_dfs_depth, "invariant");

    72 

    73   // Depth-first search, starting from a BFS egde

    74   DFSClosure dfs;

    75   start_edge->pointee()->oop_iterate(&dfs);

    76 }

    77 

    78 void DFSClosure::find_leaks_from_root_set(EdgeStore* edge_store,

    79                                           BitSet* mark_bits) {

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

    81   assert(mark_bits != NULL, "invariant");

    82 

    83   _edge_store = edge_store;

    84   _mark_bits = mark_bits;

    85   _start_edge = NULL;

    86 

    87   // Mark root set, to avoid going sideways

    88   _max_depth = 1;

    89   _ignore_root_set = false;

    90   DFSClosure dfs1;

    91   RootSetClosure::process_roots(&dfs1);

    92 

    93   // Depth-first search

    94   _max_depth = max_dfs_depth;

    95   _ignore_root_set = true;

    96   assert(_start_edge == NULL, "invariant");

    97   DFSClosure dfs2;

    98   RootSetClosure::process_roots(&dfs2);

    99 }

   100 

   101 void DFSClosure::closure_impl(const oop* reference, const oop pointee) {

   102   assert(pointee != NULL, "invariant");

   103   assert(reference != NULL, "invariant");

   104 

   105   if (GranularTimer::is_finished()) {

   106      return;

   107   }

   108   if (_depth == 0 && _ignore_root_set) {

   109     // Root set is already marked, but we want

   110     // to continue, so skip is_marked check.

   111     assert(_mark_bits->is_marked(pointee), "invariant");

   112   } else {

   113     if (_mark_bits->is_marked(pointee)) {

   114       return;

   115     }

   116   }

   117 

   118   _reference = reference;

   119   _mark_bits->mark_obj(pointee);

   120   assert(_mark_bits->is_marked(pointee), "invariant");

   121 

   122   // is the pointee a sample object?

   123   if (NULL == pointee->mark()) {

   124     add_chain();

   125   }

   126 

   127   assert(_max_depth >= 1, "invariant");

   128   if (_depth < _max_depth - 1) {

   129     DFSClosure next_level(this, _depth + 1);

   130     pointee->oop_iterate(&next_level);

   131   }

   132 }

   133 

   134 void DFSClosure::add_chain() {

   135   const size_t length = _start_edge == NULL ? _depth + 1 :

   136                         _start_edge->distance_to_root() + 1 + _depth + 1;

   137 

   138   ResourceMark rm;

   139   Edge* const chain = NEW_RESOURCE_ARRAY(Edge, length);

   140   size_t idx = 0;

   141 

   142   // aggregate from depth-first search

   143   const DFSClosure* c = this;

   144   while (c != NULL) {

   145     chain[idx++] = Edge(NULL, c->reference());

   146     c = c->parent();

   147   }

   148 

   149   assert(idx == _depth + 1, "invariant");

   150 

   151   // aggregate from breadth-first search

   152   const Edge* current = _start_edge;

   153   while (current != NULL) {

   154     chain[idx++] = Edge(NULL, current->reference());

   155     current = current->parent();

   156   }

   157   assert(idx == length, "invariant");

   158   _edge_store->add_chain(chain, length);

   159 }

   160 

   161 void DFSClosure::do_oop(oop* ref) {

   162   assert(ref != NULL, "invariant");

   163   assert(is_aligned(ref, HeapWordSize), "invariant");

   164   const oop pointee = *ref;

   165   if (pointee != NULL) {

   166     closure_impl(ref, pointee);

   167   }

   168 }

   169 

   170 void DFSClosure::do_oop(narrowOop* ref) {

   171   assert(ref != NULL, "invariant");

   172   assert(is_aligned(ref, sizeof(narrowOop)), "invariant");

   173   const oop pointee = RawAccess<>::oop_load(ref);

   174   if (pointee != NULL) {

   175     closure_impl(UnifiedOop::encode(ref), pointee);

   176   }

   177 }