1 /*

     2  * Copyright (c) 2019, Red Hat, Inc. All rights reserved.

     3  *

     4  * This code is free software; you can redistribute it and/or modify it

     5  * under the terms of the GNU General Public License version 2 only, as

     6  * published by the Free Software Foundation.

     7  *

     8  * This code is distributed in the hope that it will be useful, but WITHOUT

     9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    11  * version 2 for more details (a copy is included in the LICENSE file that

    12  * accompanied this code).

    13  *

    14  * You should have received a copy of the GNU General Public License version

    15  * 2 along with this work; if not, write to the Free Software Foundation,

    16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    17  *

    18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    19  * or visit www.oracle.com if you need additional information or have any

    20  * questions.

    21  *

    22  */

    23 

    24 #ifndef SHARE_SERVICES_THREADSTACKTRACKER_HPP

    25 #define SHARE_SERVICES_THREADSTACKTRACKER_HPP

    26 

    27 #if INCLUDE_NMT

    28 

    29 #include "services/allocationSite.hpp"

    30 #include "services/mallocSiteTable.hpp"

    31 #include "services/nmtCommon.hpp"

    32 #include "utilities/nativeCallStack.hpp"

    33 #include "utilities/linkedlist.hpp"

    34 

    35 class SimpleThreadStackSite;

    36 

    37 class SimpleThreadStack {

    38   friend class SimpleThreadStackSite;

    39 private:

    40   address _base;

    41   size_t  _size;

    42 public:

    43   SimpleThreadStack() : _base(NULL), _size(0) { }

    44   bool equals(const SimpleThreadStack& s) const {

    45     return base() == s.base();

    46   }

    47 

    48   size_t  size() const { return _size; }

    49   address base() const { return _base; }

    50 private:

    51   void set_size(size_t size)  { _size = size; }

    52   void set_base(address base) { _base = base; }

    53 };

    54 

    55 class SimpleThreadStackSite : public AllocationSite<SimpleThreadStack> {

    56 public:

    57   SimpleThreadStackSite(address base, size_t size, const NativeCallStack& stack) :

    58     AllocationSite<SimpleThreadStack>(stack, mtThreadStack) {

    59     data()->set_size(size);

    60     data()->set_base(base);

    61   }

    62 

    63   SimpleThreadStackSite(address base, size_t size) :

    64     AllocationSite<SimpleThreadStack>(NativeCallStack::empty_stack(), mtThreadStack) {

    65     data()->set_base(base);

    66     data()->set_size(size);

    67   }

    68 

    69   bool equals(const SimpleThreadStackSite& mts) const {

    70     bool eq = base() == mts.base();

    71     assert(!eq || size() == mts.size(), "Must match");

    72     return eq;

    73   }

    74 

    75   size_t  size() const { return peek()->size(); }

    76   address base() const { return peek()->base(); }

    77 };

    78 

    79   /*

    80    * Most of platforms, that hotspot support, have their thread stacks backed by

    81    * virtual memory by default. For these cases, thread stack tracker simply

    82    * delegates tracking to virtual memory tracker.

    83    * However, there are exceptions, (e.g. AIX), that platforms can provide stacks

    84    * that are not page aligned. A hypothetical VM implementation, it can provide

    85    * it own stacks. In these case, track_as_vm() should return false and manage

    86    * stack tracking by this tracker internally.

    87    * During memory snapshot, tracked thread stacks memory data is walked and stored

    88    * along with malloc'd data inside baseline. The regions are not scanned and assumed

    89    * all committed for now. Can add scanning phase when there is a need.

    90    */

    91 class ThreadStackTracker : AllStatic {

    92 private:

    93   static volatile size_t _thread_count;

    94 

    95   static int compare_thread_stack_base(const SimpleThreadStackSite& s1, const SimpleThreadStackSite& s2);

    96   static SortedLinkedList<SimpleThreadStackSite, compare_thread_stack_base>* _simple_thread_stacks;

    97 public:

    98   // Late phase initialization

    99   static bool late_initialize(NMT_TrackingLevel level);

   100   static bool transition(NMT_TrackingLevel from, NMT_TrackingLevel to);

   101 

   102   static void new_thread_stack(void* base, size_t size, const NativeCallStack& stack);

   103   static void delete_thread_stack(void* base, size_t size);

   104 

   105   static bool   track_as_vm()  { return AIX_ONLY(false) NOT_AIX(true); }

   106   static size_t thread_count() { return _thread_count; }

   107 

   108   // Snapshot support. Piggyback thread stack data in malloc slot, NMT always handles

   109   // thread stack slot specially since beginning.

   110   static bool walk_simple_thread_stack_site(MallocSiteWalker* walker);

   111 };

   112 

   113 #endif // INCLUDE_NMT

   114 #endif // SHARE_SERVICES_THREADSTACKTRACKER_HPP