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src/share/vm/runtime/sweeper.hpp

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rev 13265 : 8180932: Parallelize safepoint cleanup
Summary: Provide infrastructure to do safepoint cleanup tasks using parallel worker threads
Reviewed-by: dholmes, rehn, dcubed, thartmann
   1 /*
   2  * Copyright (c) 1997, 2016, 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 #ifndef SHARE_VM_RUNTIME_SWEEPER_HPP
  26 #define SHARE_VM_RUNTIME_SWEEPER_HPP
  27 
  28 class WhiteBox;
  29 
  30 #include "code/codeCache.hpp"
  31 #include "utilities/ticks.hpp"
  32 


  33 // An NmethodSweeper is an incremental cleaner for:
  34 //    - cleanup inline caches
  35 //    - reclamation of nmethods
  36 // Removing nmethods from the code cache includes two operations
  37 //  1) mark active nmethods
  38 //     Is done in 'mark_active_nmethods()'. This function is called at a
  39 //     safepoint and marks all nmethods that are active on a thread's stack.
  40 //  2) sweep nmethods
  41 //     Is done in sweep_code_cache(). This function is the only place in the
  42 //     sweeper where memory is reclaimed. Note that sweep_code_cache() is not
  43 //     called at a safepoint. However, sweep_code_cache() stops executing if
  44 //     another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
  45 //     and sweep_code_cache() cannot execute at the same time.
  46 //     To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
  47 //     be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
  48 //     invalidation, and (iv) being replaced by a different method version (tiered
  49 //     compilation). Not-entrant nmethods cannot be called by Java threads, but they
  50 //     can still be active on the stack. To ensure that active nmethods are not reclaimed,
  51 //     we have to wait until the next marking phase has completed. If a not-entrant
  52 //     nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely


  97   static void handle_safepoint_request();
  98   static void do_stack_scanning();
  99   static void possibly_sweep();
 100  public:
 101   static long traversal_count()              { return _traversals; }
 102   static int  total_nof_methods_reclaimed()  { return _total_nof_methods_reclaimed; }
 103   static const Tickspan total_time_sweeping()      { return _total_time_sweeping; }
 104   static const Tickspan peak_sweep_time()          { return _peak_sweep_time; }
 105   static const Tickspan peak_sweep_fraction_time() { return _peak_sweep_fraction_time; }
 106   static void log_sweep(const char* msg, const char* format = NULL, ...) ATTRIBUTE_PRINTF(2, 3);
 107 
 108 
 109 #ifdef ASSERT
 110   // Keep track of sweeper activity in the ring buffer
 111   static void record_sweep(CompiledMethod* nm, int line);
 112   static void report_events(int id, address entry);
 113   static void report_events();
 114 #endif
 115 
 116   static void mark_active_nmethods();      // Invoked at the end of each safepoint

 117   static void sweeper_loop();
 118   static void notify(int code_blob_type);  // Possibly start the sweeper thread.
 119   static void force_sweep();
 120 
 121   static int hotness_counter_reset_val();
 122   static void report_state_change(nmethod* nm);
 123   static void possibly_enable_sweeper();
 124   static void possibly_flush(nmethod* nm);
 125   static void print();   // Printing/debugging
 126 };
 127 
 128 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP
   1 /*
   2  * Copyright (c) 1997, 2017, 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 #ifndef SHARE_VM_RUNTIME_SWEEPER_HPP
  26 #define SHARE_VM_RUNTIME_SWEEPER_HPP
  27 
  28 class WhiteBox;
  29 
  30 #include "code/codeCache.hpp"
  31 #include "utilities/ticks.hpp"
  32 
  33 class CodeBlobClosure;
  34 
  35 // An NmethodSweeper is an incremental cleaner for:
  36 //    - cleanup inline caches
  37 //    - reclamation of nmethods
  38 // Removing nmethods from the code cache includes two operations
  39 //  1) mark active nmethods
  40 //     Is done in 'mark_active_nmethods()'. This function is called at a
  41 //     safepoint and marks all nmethods that are active on a thread's stack.
  42 //  2) sweep nmethods
  43 //     Is done in sweep_code_cache(). This function is the only place in the
  44 //     sweeper where memory is reclaimed. Note that sweep_code_cache() is not
  45 //     called at a safepoint. However, sweep_code_cache() stops executing if
  46 //     another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
  47 //     and sweep_code_cache() cannot execute at the same time.
  48 //     To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
  49 //     be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
  50 //     invalidation, and (iv) being replaced by a different method version (tiered
  51 //     compilation). Not-entrant nmethods cannot be called by Java threads, but they
  52 //     can still be active on the stack. To ensure that active nmethods are not reclaimed,
  53 //     we have to wait until the next marking phase has completed. If a not-entrant
  54 //     nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely


  99   static void handle_safepoint_request();
 100   static void do_stack_scanning();
 101   static void possibly_sweep();
 102  public:
 103   static long traversal_count()              { return _traversals; }
 104   static int  total_nof_methods_reclaimed()  { return _total_nof_methods_reclaimed; }
 105   static const Tickspan total_time_sweeping()      { return _total_time_sweeping; }
 106   static const Tickspan peak_sweep_time()          { return _peak_sweep_time; }
 107   static const Tickspan peak_sweep_fraction_time() { return _peak_sweep_fraction_time; }
 108   static void log_sweep(const char* msg, const char* format = NULL, ...) ATTRIBUTE_PRINTF(2, 3);
 109 
 110 
 111 #ifdef ASSERT
 112   // Keep track of sweeper activity in the ring buffer
 113   static void record_sweep(CompiledMethod* nm, int line);
 114   static void report_events(int id, address entry);
 115   static void report_events();
 116 #endif
 117 
 118   static void mark_active_nmethods();      // Invoked at the end of each safepoint
 119   static CodeBlobClosure* prepare_mark_active_nmethods();
 120   static void sweeper_loop();
 121   static void notify(int code_blob_type);  // Possibly start the sweeper thread.
 122   static void force_sweep();
 123 
 124   static int hotness_counter_reset_val();
 125   static void report_state_change(nmethod* nm);
 126   static void possibly_enable_sweeper();
 127   static void possibly_flush(nmethod* nm);
 128   static void print();   // Printing/debugging
 129 };
 130 
 131 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP
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