jdk8-mips64-public/hotspot: src/share/vm/runtime/safepoint.hpp@91ddc23482a4 (annotated)

src/share/vm/runtime/safepoint.hpp@91ddc23482a4 (annotated)

src/share/vm/runtime/safepoint.hpp

Thu, 24 May 2018 20:03:11 +0800

author: aoqi
date: Thu, 24 May 2018 20:03:11 +0800
changeset 8868: 91ddc23482a4
parent 6876: 710a3c8b516e
child 9852: 70aa912cebe5
permissions: -rw-r--r--

Increase MaxHeapSize for better performance on MIPS

 /*
  * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 only, as
  * published by the Free Software Foundation.
  *
  * This code is distributed in the hope that it will be useful, but WITHOUT
  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  * version 2 for more details (a copy is included in the LICENSE file that
  * accompanied this code).
  *
  * You should have received a copy of the GNU General Public License version
  * 2 along with this work; if not, write to the Free Software Foundation,
  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  *
  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  * or visit www.oracle.com if you need additional information or have any
  * questions.
  *
  */
 #ifndef SHARE_VM_RUNTIME_SAFEPOINT_HPP
 #define SHARE_VM_RUNTIME_SAFEPOINT_HPP
 #include "asm/assembler.hpp"
 #include "code/nmethod.hpp"
 #include "memory/allocation.hpp"
 #include "runtime/extendedPC.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/os.hpp"
 #include "utilities/ostream.hpp"
 //
 // Safepoint synchronization
 ////
 // The VMThread or CMS_thread uses the SafepointSynchronize::begin/end
 // methods to enter/exit a safepoint region. The begin method will roll
 // all JavaThreads forward to a safepoint.
 //
 // JavaThreads must use the ThreadSafepointState abstraction (defined in
 // thread.hpp) to indicate that that they are at a safepoint.
 //
 // The Mutex/Condition variable and ObjectLocker classes calls the enter/
 // exit safepoint methods, when a thread is blocked/restarted. Hence, all mutex exter/
 // exit points *must* be at a safepoint.
 class ThreadSafepointState;
 class SnippetCache;
 class nmethod;
 //
 // Implements roll-forward to safepoint (safepoint synchronization)
 //
 class SafepointSynchronize : AllStatic {
  public:
   enum SynchronizeState {
       _not_synchronized = 0,                   // Threads not synchronized at a safepoint
                                                // Keep this value 0. See the coment in do_call_back()
       _synchronizing    = 1,                   // Synchronizing in progress
       _synchronized     = 2                    // All Java threads are stopped at a safepoint. Only VM thread is running
   };
   enum SafepointingThread {
       _null_thread  = 0,
       _vm_thread    = 1,
       _other_thread = 2
   };
   enum SafepointTimeoutReason {
     _spinning_timeout = 0,
     _blocking_timeout = 1
   };
   typedef struct {
     float  _time_stamp;                        // record when the current safepoint occurs in seconds
     int    _vmop_type;                         // type of VM operation triggers the safepoint
     int    _nof_total_threads;                 // total number of Java threads
     int    _nof_initial_running_threads;       // total number of initially seen running threads
     int    _nof_threads_wait_to_block;         // total number of threads waiting for to block
     bool   _page_armed;                        // true if polling page is armed, false otherwise
     int    _nof_threads_hit_page_trap;         // total number of threads hitting the page trap
     jlong  _time_to_spin;                      // total time in millis spent in spinning
     jlong  _time_to_wait_to_block;             // total time in millis spent in waiting for to block
     jlong  _time_to_do_cleanups;               // total time in millis spent in performing cleanups
     jlong  _time_to_sync;                      // total time in millis spent in getting to _synchronized
     jlong  _time_to_exec_vmop;                 // total time in millis spent in vm operation itself
   } SafepointStats;
  private:
   static volatile SynchronizeState _state;     // Threads might read this flag directly, without acquireing the Threads_lock
   static volatile int _waiting_to_block;       // number of threads we are waiting for to block
   static int _current_jni_active_count;        // Counts the number of active critical natives during the safepoint
   // This counter is used for fast versions of jni_Get<Primitive>Field.
   // An even value means there is no ongoing safepoint operations.
   // The counter is incremented ONLY at the beginning and end of each
   // safepoint. The fact that Threads_lock is held throughout each pair of
   // increments (at the beginning and end of each safepoint) guarantees
   // race freedom.
 public:
   static volatile int _safepoint_counter;
 private:
   static long       _end_of_last_safepoint;     // Time of last safepoint in milliseconds
   // statistics
   static jlong            _safepoint_begin_time;     // time when safepoint begins
   static SafepointStats*  _safepoint_stats;          // array of SafepointStats struct
   static int              _cur_stat_index;           // current index to the above array
   static julong           _safepoint_reasons[];      // safepoint count for each VM op
   static julong           _coalesced_vmop_count;     // coalesced vmop count
   static jlong            _max_sync_time;            // maximum sync time in nanos
   static jlong            _max_vmop_time;            // maximum vm operation time in nanos
   static float            _ts_of_current_safepoint;  // time stamp of current safepoint in seconds
   static void begin_statistics(int nof_threads, int nof_running);
   static void update_statistics_on_spin_end();
   static void update_statistics_on_sync_end(jlong end_time);
   static void update_statistics_on_cleanup_end(jlong end_time);
   static void end_statistics(jlong end_time);
   static void print_statistics();
   inline static void inc_page_trap_count() {
     Atomic::inc(&_safepoint_stats[_cur_stat_index]._nof_threads_hit_page_trap);
   }
   // For debug long safepoint
   static void print_safepoint_timeout(SafepointTimeoutReason timeout_reason);
 public:
   // Main entry points
   // Roll all threads forward to safepoint. Must be called by the
   // VMThread or CMS_thread.
   static void begin();
   static void end();                    // Start all suspended threads again...
   static bool safepoint_safe(JavaThread *thread, JavaThreadState state);
   static void check_for_lazy_critical_native(JavaThread *thread, JavaThreadState state);
   // Query
   inline static bool is_at_safepoint()   { return _state == _synchronized;  }
   inline static bool is_synchronizing()  { return _state == _synchronizing;  }
   inline static bool do_call_back() {
     return (_state != _not_synchronized);
   }
   inline static void increment_jni_active_count() {
     assert_locked_or_safepoint(Safepoint_lock);
     _current_jni_active_count++;
   }
   // Called when a thread volantary blocks
   static void   block(JavaThread *thread);
   static void   signal_thread_at_safepoint()              { _waiting_to_block--; }
   // Exception handling for page polling
   static void handle_polling_page_exception(JavaThread *thread);
   // VM Thread interface for determining safepoint rate
   static long last_non_safepoint_interval() {
     return os::javaTimeMillis() - _end_of_last_safepoint;
   }
   static long end_of_last_safepoint() {
     return _end_of_last_safepoint;
   }
   static bool is_cleanup_needed();
   static void do_cleanup_tasks();
   // debugging
   static void print_state()                                PRODUCT_RETURN;
   static void safepoint_msg(const char* format, ...) ATTRIBUTE_PRINTF(1, 2) PRODUCT_RETURN;
   static void deferred_initialize_stat();
   static void print_stat_on_exit();
   inline static void inc_vmop_coalesced_count() { _coalesced_vmop_count++; }
   static void set_is_at_safepoint()                        { _state = _synchronized; }
   static void set_is_not_at_safepoint()                    { _state = _not_synchronized; }
   // assembly support
   static address address_of_state()                        { return (address)&_state; }
   static address safepoint_counter_addr()                  { return (address)&_safepoint_counter; }
 };
 // State class for a thread suspended at a safepoint
 class ThreadSafepointState: public CHeapObj<mtInternal> {
  public:
   // These states are maintained by VM thread while threads are being brought
   // to a safepoint.  After SafepointSynchronize::end(), they are reset to
   // _running.
   enum suspend_type {
     _running                =  0, // Thread state not yet determined (i.e., not at a safepoint yet)
     _at_safepoint           =  1, // Thread at a safepoint (f.ex., when blocked on a lock)
     _call_back              =  2  // Keep executing and wait for callback (if thread is in interpreted or vm)
   };
  private:
   volatile bool _at_poll_safepoint;  // At polling page safepoint (NOT a poll return safepoint)
   // Thread has called back the safepoint code (for debugging)
   bool                           _has_called_back;
   JavaThread *                   _thread;
   volatile suspend_type          _type;
   JavaThreadState                _orig_thread_state;
  public:
   ThreadSafepointState(JavaThread *thread);
   // examine/roll-forward/restart
   void examine_state_of_thread();
   void roll_forward(suspend_type type);
   void restart();
   // Query
   JavaThread*  thread() const         { return _thread; }
   suspend_type type() const           { return _type; }
   bool         is_running() const     { return (_type==_running); }
   JavaThreadState orig_thread_state() const { return _orig_thread_state; }
   // Support for safepoint timeout (debugging)
   bool has_called_back() const                   { return _has_called_back; }
   void set_has_called_back(bool val)             { _has_called_back = val; }
   bool              is_at_poll_safepoint() { return _at_poll_safepoint; }
   void              set_at_poll_safepoint(bool val) { _at_poll_safepoint = val; }
   void handle_polling_page_exception();
   // debugging
   void print_on(outputStream* st) const;
   void print() const                        { print_on(tty); }
   // Initialize
   static void create(JavaThread *thread);
   static void destroy(JavaThread *thread);
   void safepoint_msg(const char* format, ...) ATTRIBUTE_PRINTF(2, 3) {
     if (ShowSafepointMsgs) {
       va_list ap;
       va_start(ap, format);
       tty->vprint_cr(format, ap);
       va_end(ap);
     }
   }
 };
 #endif // SHARE_VM_RUNTIME_SAFEPOINT_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/runtime/safepoint.hpp@91ddc23482a4 (annotated)

src/share/vm/runtime/safepoint.hpp