jdk8-mips64-public/hotspot: src/share/vm/gc_implementation/shared/vmGCOperations.hpp@9f28a4cac6d9 (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.hpp@9f28a4cac6d9 (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.hpp

Wed, 31 Jul 2019 14:28:51 -0400

author: kbarrett
date: Wed, 31 Jul 2019 14:28:51 -0400
changeset 9787: 9f28a4cac6d9
parent 7688: a4ad5d51d29c
child 9806: 758c07667682
permissions: -rw-r--r--

8048556: Unnecessary GCLocker-initiated young GCs
Summary: Fixed recognition of unnecessary GCLocker collections.
Reviewed-by: pliden, tschatzl
Contributed-by: johnc@azul.com

 /*
  * Copyright (c) 2005, 2015, 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_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP
 #include "gc_implementation/shared/gcId.hpp"
 #include "memory/heapInspection.hpp"
 #include "runtime/handles.hpp"
 #include "runtime/jniHandles.hpp"
 #include "runtime/synchronizer.hpp"
 #include "runtime/vm_operations.hpp"
 #include "prims/jvmtiExport.hpp"
 // The following class hierarchy represents
 // a set of operations (VM_Operation) related to GC.
 //
 //  VM_Operation
 //      VM_GC_Operation
 //          VM_GC_HeapInspection
 //          VM_GenCollectFull
 //          VM_GenCollectFullConcurrent
 //          VM_ParallelGCSystemGC
 //          VM_CollectForAllocation
 //              VM_GenCollectForAllocation
 //              VM_ParallelGCFailedAllocation
 //  VM_GC_Operation
 //   - implements methods common to all classes in the hierarchy:
 //     prevents multiple gc requests and manages lock on heap;
 //
 //  VM_GC_HeapInspection
 //   - prints class histogram on SIGBREAK if PrintClassHistogram
 //     is specified; and also the attach "inspectheap" operation
 //
 //  VM_CollectForAllocation
 //  VM_GenCollectForAllocation
 //  VM_ParallelGCFailedAllocation
 //   - this operation is invoked when allocation is failed;
 //     operation performs garbage collection and tries to
 //     allocate afterwards;
 //
 //  VM_GenCollectFull
 //  VM_GenCollectFullConcurrent
 //  VM_ParallelGCSystemGC
 //   - these operations preform full collection of heaps of
 //     different kind
 //
 class VM_GC_Operation: public VM_Operation {
  protected:
   BasicLock      _pending_list_basic_lock; // for refs pending list notification (PLL)
   uint           _gc_count_before;         // gc count before acquiring PLL
   uint           _full_gc_count_before;    // full gc count before acquiring PLL
   bool           _full;                    // whether a "full" collection
   bool           _prologue_succeeded;      // whether doit_prologue succeeded
   GCCause::Cause _gc_cause;                // the putative cause for this gc op
   bool           _gc_locked;               // will be set if gc was locked
   virtual bool skip_operation() const;
   // java.lang.ref.Reference support
   void acquire_pending_list_lock();
   void release_and_notify_pending_list_lock();
  public:
   VM_GC_Operation(uint gc_count_before,
                   GCCause::Cause _cause,
                   uint full_gc_count_before = 0,
                   bool full = false) {
     _full = full;
     _prologue_succeeded = false;
     _gc_count_before    = gc_count_before;
     // A subclass constructor will likely overwrite the following
     _gc_cause           = _cause;
     _gc_locked = false;
     _full_gc_count_before = full_gc_count_before;
     // In ParallelScavengeHeap::mem_allocate() collections can be
     // executed within a loop and _all_soft_refs_clear can be set
     // true after they have been cleared by a collection and another
     // collection started so that _all_soft_refs_clear can be true
     // when this collection is started.  Don't assert that
     // _all_soft_refs_clear have to be false here even though
     // mutators have run.  Soft refs will be cleared again in this
     // collection.
   }
   ~VM_GC_Operation() {
     CollectedHeap* ch = Universe::heap();
     ch->collector_policy()->set_all_soft_refs_clear(false);
   }
   // Acquire the reference synchronization lock
   virtual bool doit_prologue();
   // Do notifyAll (if needed) and release held lock
   virtual void doit_epilogue();
   virtual bool allow_nested_vm_operations() const  { return true; }
   bool prologue_succeeded() const { return _prologue_succeeded; }
   void set_gc_locked() { _gc_locked = true; }
   bool gc_locked() const  { return _gc_locked; }
   static void notify_gc_begin(bool full = false);
   static void notify_gc_end();
 };
 class VM_GC_HeapInspection: public VM_GC_Operation {
  private:
   outputStream* _out;
   bool _full_gc;
   bool _csv_format; // "comma separated values" format for spreadsheet.
   bool _print_help;
   bool _print_class_stats;
   const char* _columns;
  public:
   VM_GC_HeapInspection(outputStream* out, bool request_full_gc) :
     VM_GC_Operation(0 /* total collections,      dummy, ignored */,
                     GCCause::_heap_inspection /* GC Cause */,
 /* total full collections, dummy, ignored */,
                     request_full_gc) {
     _out = out;
     _full_gc = request_full_gc;
     _csv_format = false;
     _print_help = false;
     _print_class_stats = false;
     _columns = NULL;
   }
   ~VM_GC_HeapInspection() {}
   virtual VMOp_Type type() const { return VMOp_GC_HeapInspection; }
   virtual bool skip_operation() const;
   virtual bool doit_prologue();
   virtual void doit();
   void set_csv_format(bool value) {_csv_format = value;}
   void set_print_help(bool value) {_print_help = value;}
   void set_print_class_stats(bool value) {_print_class_stats = value;}
   void set_columns(const char* value) {_columns = value;}
  protected:
   bool collect();
 };
 class VM_CollectForAllocation : public VM_GC_Operation {
  protected:
   size_t    _word_size; // Size of object to be allocated (in number of words)
   HeapWord* _result;    // Allocation result (NULL if allocation failed)
  public:
   VM_CollectForAllocation(size_t word_size, uint gc_count_before, GCCause::Cause cause);
   HeapWord* result() const {
     return _result;
   }
 };
 class VM_GenCollectForAllocation : public VM_CollectForAllocation {
  private:
   bool        _tlab;                       // alloc is of a tlab.
  public:
   VM_GenCollectForAllocation(size_t word_size,
                              bool tlab,
                              uint gc_count_before)
     : VM_CollectForAllocation(word_size, gc_count_before, GCCause::_allocation_failure),
       _tlab(tlab) {
     assert(word_size != 0, "An allocation should always be requested with this operation.");
   }
   ~VM_GenCollectForAllocation()  {}
   virtual VMOp_Type type() const { return VMOp_GenCollectForAllocation; }
   virtual void doit();
 };
 // VM operation to invoke a collection of the heap as a
 // GenCollectedHeap heap.
 class VM_GenCollectFull: public VM_GC_Operation {
  private:
   int _max_level;
  public:
   VM_GenCollectFull(uint gc_count_before,
                     uint full_gc_count_before,
                     GCCause::Cause gc_cause,
                     int max_level);
   ~VM_GenCollectFull() {}
   virtual VMOp_Type type() const { return VMOp_GenCollectFull; }
   virtual void doit();
 };
 class VM_CollectForMetadataAllocation: public VM_GC_Operation {
  private:
   MetaWord*                _result;
   size_t                   _size;     // size of object to be allocated
   Metaspace::MetadataType  _mdtype;
   ClassLoaderData*         _loader_data;
  public:
   VM_CollectForMetadataAllocation(ClassLoaderData* loader_data,
                                   size_t size, Metaspace::MetadataType mdtype,
                                   uint gc_count_before,
                                   uint full_gc_count_before,
                                   GCCause::Cause gc_cause);
   virtual VMOp_Type type() const { return VMOp_CollectForMetadataAllocation; }
   virtual void doit();
   MetaWord* result() const       { return _result; }
   bool initiate_concurrent_GC();
 };
 class SvcGCMarker : public StackObj {
  private:
   JvmtiGCMarker _jgcm;
  public:
   typedef enum { MINOR, FULL, OTHER } reason_type;
   SvcGCMarker(reason_type reason ) {
     VM_GC_Operation::notify_gc_begin(reason == FULL);
   }
   ~SvcGCMarker() {
     VM_GC_Operation::notify_gc_end();
   }
 };
 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_VMGCOPERATIONS_HPP

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/gc_implementation/shared/vmGCOperations.hpp@9f28a4cac6d9 (annotated)

src/share/vm/gc_implementation/shared/vmGCOperations.hpp