/*
* Copyright (c) 2005, 2019, 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
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* published by the Free Software Foundation.
*
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* 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).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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#ifndef SHARE_GC_SHARED_GCVMOPERATIONS_HPP
#define SHARE_GC_SHARED_GCVMOPERATIONS_HPP
#include "gc/shared/collectedHeap.hpp"
#include "gc/shared/genCollectedHeap.hpp"
#include "memory/heapInspection.hpp"
#include "memory/metaspace.hpp"
#include "prims/jvmtiExport.hpp"
#include "runtime/handles.hpp"
#include "runtime/jniHandles.hpp"
#include "runtime/synchronizer.hpp"
#include "runtime/vmOperations.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:
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;
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();
// 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 */,
0 /* 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 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:
GenCollectedHeap::GenerationType _max_generation;
public:
VM_GenCollectFull(uint gc_count_before,
uint full_gc_count_before,
GCCause::Cause gc_cause,
GenCollectedHeap::GenerationType max_generation)
: VM_GC_Operation(gc_count_before, gc_cause, full_gc_count_before,
max_generation != GenCollectedHeap::YoungGen /* full */),
_max_generation(max_generation) { }
~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, CONCURRENT } reason_type;
SvcGCMarker(reason_type reason ) {
VM_GC_Operation::notify_gc_begin(reason == FULL);
}
~SvcGCMarker() {
VM_GC_Operation::notify_gc_end();
}
};
#endif // SHARE_GC_SHARED_GCVMOPERATIONS_HPP