jdk8-mips64-public/hotspot: src/share/vm/runtime/sweeper.hpp@9ce110b1d14a

     1 /*

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     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.

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     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  *

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    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

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    23  */

    25 #ifndef SHARE_VM_RUNTIME_SWEEPER_HPP

    26 #define SHARE_VM_RUNTIME_SWEEPER_HPP

    28 // An NmethodSweeper is an incremental cleaner for:

    29 //    - cleanup inline caches

    30 //    - reclamation of unreferences zombie nmethods

    31 //

    33 class NMethodSweeper : public AllStatic {

    34   static long      _traversals;   // Stack traversal count

    35   static nmethod*  _current;      // Current nmethod

    36   static int       _seen;         // Nof. nmethod we have currently processed in current pass of CodeCache

    38   static volatile int  _invocations;   // No. of invocations left until we are completed with this pass

    39   static volatile int  _sweep_started; // Flag to control conc sweeper

    41   //The following are reset in scan_stacks and synchronized by the safepoint

    42   static bool      _resweep;           // Indicates that a change has happend and we want another sweep,

    43                                        // always checked and reset at a safepoint so memory will be in sync.

    44   static int       _locked_seen;       // Number of locked nmethods encountered during the scan

    45   static int       _not_entrant_seen_on_stack; // Number of not entrant nmethod were are still on stack

    46   static jint      _flush_token;       // token that guards method flushing, making sure it is executed only once.

    48   // These are set during a flush, a VM-operation

    49   static long      _last_flush_traversal_id; // trav number at last flush unloading

    50   static jlong     _last_full_flush_time;    // timestamp of last emergency unloading

    52   // These are synchronized by the _sweep_started token

    53   static int       _highest_marked;   // highest compile id dumped at last emergency unloading

    54   static int       _dead_compile_ids; // number of compile ids that where not in the cache last flush

    56   static void process_nmethod(nmethod *nm);

    57   static void release_nmethod(nmethod* nm);

    59   static void log_sweep(const char* msg, const char* format = NULL, ...);

    60   static bool sweep_in_progress();

    62  public:

    63   static long traversal_count() { return _traversals; }

    65 #ifdef ASSERT

    66   // Keep track of sweeper activity in the ring buffer

    67   static void record_sweep(nmethod* nm, int line);

    68   static void report_events(int id, address entry);

    69   static void report_events();

    70 #endif

    72   static void scan_stacks();      // Invoked at the end of each safepoint

    73   static void sweep_code_cache(); // Concurrent part of sweep job

    74   static void possibly_sweep();   // Compiler threads call this to sweep

    76   static void notify(nmethod* nm) {

    77     // Request a new sweep of the code cache from the beginning. No

    78     // need to synchronize the setting of this flag since it only

    79     // changes to false at safepoint so we can never overwrite it with false.

    80      _resweep = true;

    81   }

    83   static void handle_full_code_cache(bool is_full); // Called by compilers who fail to allocate

    84   static void speculative_disconnect_nmethods(bool was_full);   // Called by vm op to deal with alloc failure

    85 };

    87 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP

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