jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/g1/satbQueue.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/satbQueue.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/satbQueue.hpp

Fri, 10 Oct 2014 15:51:58 +0200

author: tschatzl
date: Fri, 10 Oct 2014 15:51:58 +0200
changeset 7257: e7d0505c8a30
parent 6992: 2c6ef90f030a
child 7476: c2844108a708
permissions: -rw-r--r--

8059758: Footprint regressions with JDK-8038423
Summary: Changes in JDK-8038423 always initialize (zero out) virtual memory used for auxiliary data structures. This causes a footprint regression for G1 in startup benchmarks. This is because they do not touch that memory at all, so the operating system does not actually commit these pages. The fix is to, if the initialization value of the data structures matches the default value of just committed memory (=0), do not do anything.
Reviewed-by: jwilhelm, brutisso

 /*
  * Copyright (c) 2001, 2012, 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
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 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
 #include "gc_implementation/g1/ptrQueue.hpp"
 class ObjectClosure;
 class JavaThread;
 class SATBMarkQueueSet;
 // A ptrQueue whose elements are "oops", pointers to object heads.
 class ObjPtrQueue: public PtrQueue {
   friend class Threads;
   friend class SATBMarkQueueSet;
   friend class G1RemarkThreadsClosure;
 private:
   // Filter out unwanted entries from the buffer.
   void filter();
   // Apply the closure to all elements.
   void apply_closure(ObjectClosure* cl);
   // Apply the closure to all elements and empty the buffer;
   void apply_closure_and_empty(ObjectClosure* cl);
   // Apply the closure to all elements of "buf", down to "index" (inclusive.)
   static void apply_closure_to_buffer(ObjectClosure* cl,
                                       void** buf, size_t index, size_t sz);
 public:
   ObjPtrQueue(PtrQueueSet* qset, bool perm = false) :
     // SATB queues are only active during marking cycles. We create
     // them with their active field set to false. If a thread is
     // created during a cycle and its SATB queue needs to be activated
     // before the thread starts running, we'll need to set its active
     // field to true. This is done in JavaThread::initialize_queues().
     PtrQueue(qset, perm, false /* active */) { }
   // Overrides PtrQueue::flush() so that it can filter the buffer
   // before it is flushed.
   virtual void flush();
   // Overrides PtrQueue::should_enqueue_buffer(). See the method's
   // definition for more information.
   virtual bool should_enqueue_buffer();
 #ifndef PRODUCT
   // Helpful for debugging
   void print(const char* name);
   static void print(const char* name, void** buf, size_t index, size_t sz);
 #endif // PRODUCT
   void verify_oops_in_buffer() NOT_DEBUG_RETURN;
 };
 class SATBMarkQueueSet: public PtrQueueSet {
   ObjectClosure* _closure;
   ObjectClosure** _par_closures;  // One per ParGCThread.
   ObjPtrQueue _shared_satb_queue;
   // Utility function to support sequential and parallel versions.  If
   // "par" is true, then "worker" is the par thread id; if "false", worker
   // is ignored.
   bool apply_closure_to_completed_buffer_work(bool par, uint worker);
 #ifdef ASSERT
   void dump_active_states(bool expected_active);
   void verify_active_states(bool expected_active);
 #endif // ASSERT
 public:
   SATBMarkQueueSet();
   void initialize(Monitor* cbl_mon, Mutex* fl_lock,
                   int process_completed_threshold,
                   Mutex* lock);
   static void handle_zero_index_for_thread(JavaThread* t);
   // Apply "set_active(active)" to all SATB queues in the set. It should be
   // called only with the world stopped. The method will assert that the
   // SATB queues of all threads it visits, as well as the SATB queue
   // set itself, has an active value same as expected_active.
   void set_active_all_threads(bool active, bool expected_active);
   // Filter all the currently-active SATB buffers.
   void filter_thread_buffers();
   // Register "blk" as "the closure" for all queues.  Only one such closure
   // is allowed.  The "apply_closure_to_completed_buffer" method will apply
   // this closure to a completed buffer, and "iterate_closure_all_threads"
   // applies it to partially-filled buffers (the latter should only be done
   // with the world stopped).
   void set_closure(ObjectClosure* closure);
   // Set the parallel closures: pointer is an array of pointers to
   // closures, one for each parallel GC thread.
   void set_par_closure(int i, ObjectClosure* closure);
   // If there exists some completed buffer, pop it, then apply the
   // registered closure to all its elements, and return true.  If no
   // completed buffers exist, return false.
   bool apply_closure_to_completed_buffer() {
     return apply_closure_to_completed_buffer_work(false, 0);
   }
   // Parallel version of the above.
   bool par_apply_closure_to_completed_buffer(uint worker) {
     return apply_closure_to_completed_buffer_work(true, worker);
   }
   // Apply the given closure on enqueued and currently-active buffers
   // respectively. Both methods are read-only, i.e., they do not
   // modify any of the buffers.
   void iterate_completed_buffers_read_only(ObjectClosure* cl);
   void iterate_thread_buffers_read_only(ObjectClosure* cl);
 #ifndef PRODUCT
   // Helpful for debugging
   void print_all(const char* msg);
 #endif // PRODUCT
   ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
   // If a marking is being abandoned, reset any unprocessed log buffers.
   void abandon_partial_marking();
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/g1/satbQueue.hpp@e7d0505c8a30 (annotated)

src/share/vm/gc_implementation/g1/satbQueue.hpp