src/hotspot/share/gc/g1/g1Allocator.hpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2014, 2018, 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_G1_G1ALLOCATOR_HPP
 #define SHARE_VM_GC_G1_G1ALLOCATOR_HPP

 #include "gc/g1/g1AllocRegion.hpp"
 #include "gc/g1/g1InCSetState.hpp"
 #include "gc/shared/collectedHeap.hpp"
 #include "gc/shared/plab.hpp"

 class EvacuationInfo;

 // Interface to keep track of which regions G1 is currently allocating into. Provides
 // some accessors (e.g. allocating into them, or getting their occupancy).
 // Also keeps track of retained regions across GCs.
 class G1Allocator : public CHeapObj<mtGC> {
   friend class VMStructs;

 private:
   G1CollectedHeap* _g1h;

   bool _survivor_is_full;
   bool _old_is_full;

   // Alloc region used to satisfy mutator allocation requests.
   MutatorAllocRegion _mutator_alloc_region;

   // Alloc region used to satisfy allocation requests by the GC for
   // survivor objects.
   SurvivorGCAllocRegion _survivor_gc_alloc_region;

   // Alloc region used to satisfy allocation requests by the GC for
   // old objects.
   OldGCAllocRegion _old_gc_alloc_region;

   HeapRegion* _retained_old_gc_alloc_region;

   bool survivor_is_full() const;
   bool old_is_full() const;

   void set_survivor_full();
   void set_old_full();

   void reuse_retained_old_region(EvacuationInfo& evacuation_info,
                                  OldGCAllocRegion* old,
                                  HeapRegion** retained);

   // Accessors to the allocation regions.
   inline MutatorAllocRegion* mutator_alloc_region();
   inline SurvivorGCAllocRegion* survivor_gc_alloc_region();
   inline OldGCAllocRegion* old_gc_alloc_region();

   // Allocation attempt during GC for a survivor object / PLAB.
   HeapWord* survivor_attempt_allocation(size_t min_word_size,
                                                size_t desired_word_size,
                                                size_t* actual_word_size);

   // Allocation attempt during GC for an old object / PLAB.
   HeapWord* old_attempt_allocation(size_t min_word_size,
                                           size_t desired_word_size,
                                           size_t* actual_word_size);
 public:
   G1Allocator(G1CollectedHeap* heap);

 #ifdef ASSERT
   // Do we currently have an active mutator region to allocate into?
   bool has_mutator_alloc_region() { return mutator_alloc_region()->get() != NULL; }
 #endif

   void init_mutator_alloc_region();
   void release_mutator_alloc_region();

   void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
   void release_gc_alloc_regions(EvacuationInfo& evacuation_info);
   void abandon_gc_alloc_regions();
   bool is_retained_old_region(HeapRegion* hr);

   // Allocate blocks of memory during mutator time.

   inline HeapWord* attempt_allocation(size_t min_word_size,
                                       size_t desired_word_size,
                                       size_t* actual_word_size);
   inline HeapWord* attempt_allocation_locked(size_t word_size);
   inline HeapWord* attempt_allocation_force(size_t word_size);

   size_t unsafe_max_tlab_alloc();
   size_t used_in_alloc_regions();

   // Allocate blocks of memory during garbage collection. Will ensure an
   // allocation region, either by picking one or expanding the
   // heap, and then allocate a block of the given size. The block
   // may not be a humongous - it must fit into a single heap region.
   HeapWord* par_allocate_during_gc(InCSetState dest,
                                    size_t word_size);

   HeapWord* par_allocate_during_gc(InCSetState dest,
                                    size_t min_word_size,
                                    size_t desired_word_size,
                                    size_t* actual_word_size);
 };

 // Manages the PLABs used during garbage collection. Interface for allocation from PLABs.
 // Needs to handle multiple contexts, extra alignment in any "survivor" area and some
 // statistics.
 class G1PLABAllocator : public CHeapObj<mtGC> {
   friend class G1ParScanThreadState;
 private:
   G1CollectedHeap* _g1h;
   G1Allocator* _allocator;

   PLAB  _surviving_alloc_buffer;
   PLAB  _tenured_alloc_buffer;
   PLAB* _alloc_buffers[InCSetState::Num];

   // The survivor alignment in effect in bytes.
   // == 0 : don't align survivors
   // != 0 : align survivors to that alignment
   // These values were chosen to favor the non-alignment case since some
   // architectures have a special compare against zero instructions.
   const uint _survivor_alignment_bytes;

   // Number of words allocated directly (not counting PLAB allocation).
   size_t _direct_allocated[InCSetState::Num];

   void flush_and_retire_stats();
   inline PLAB* alloc_buffer(InCSetState dest);

   // Calculate the survivor space object alignment in bytes. Returns that or 0 if
   // there are no restrictions on survivor alignment.
   static uint calc_survivor_alignment_bytes();

   bool may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const;
 public:
   G1PLABAllocator(G1Allocator* allocator);

   void waste(size_t& wasted, size_t& undo_wasted);

   // Allocate word_sz words in dest, either directly into the regions or by
   // allocating a new PLAB. Returns the address of the allocated memory, NULL if
   // not successful. Plab_refill_failed indicates whether an attempt to refill the
   // PLAB failed or not.
   HeapWord* allocate_direct_or_new_plab(InCSetState dest,
                                         size_t word_sz,
                                         bool* plab_refill_failed);

   // Allocate word_sz words in the PLAB of dest.  Returns the address of the
   // allocated memory, NULL if not successful.
   inline HeapWord* plab_allocate(InCSetState dest,
                                  size_t word_sz);

   inline HeapWord* allocate(InCSetState dest,
                             size_t word_sz,
                             bool* refill_failed);

   void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz);
 };

 // G1ArchiveRegionMap is a boolean array used to mark G1 regions as
 // archive regions.  This allows a quick check for whether an object
 // should not be marked because it is in an archive region.
 class G1ArchiveRegionMap : public G1BiasedMappedArray<bool> {
 protected:
   bool default_value() const { return false; }
 };

 // G1ArchiveAllocator is used to allocate memory in archive
 // regions. Such regions are not scavenged nor compacted by GC.
 // There are two types of archive regions, which are
 // differ in the kind of references allowed for the contained objects:
 //
 // - 'Closed' archive region contain no references outside of other
 //   closed archive regions. The region is immutable by GC. GC does
 //   not mark object header in 'closed' archive region.
 // - An 'open' archive region allow references to any other regions,
 //   including closed archive, open archive and other java heap regions.
 //   GC can adjust pointers and mark object header in 'open' archive region.
 class G1ArchiveAllocator : public CHeapObj<mtGC> {
 protected:
   bool _open; // Indicate if the region is 'open' archive.
   G1CollectedHeap* _g1h;

   // The current allocation region
   HeapRegion* _allocation_region;

   // Regions allocated for the current archive range.
   GrowableArray<HeapRegion*> _allocated_regions;

   // The number of bytes used in the current range.
   size_t _summary_bytes_used;

   // Current allocation window within the current region.
   HeapWord* _bottom;
   HeapWord* _top;
   HeapWord* _max;

   // Allocate a new region for this archive allocator.
   // Allocation is from the top of the reserved heap downward.
   bool alloc_new_region();

 public:
   G1ArchiveAllocator(G1CollectedHeap* g1h, bool open) :
     _g1h(g1h),
     _allocation_region(NULL),
     _allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions,
                                                          ResourceObj::C_HEAP),
                         2), true /* C_Heap */),
     _summary_bytes_used(0),
     _bottom(NULL),
     _top(NULL),
     _max(NULL),
     _open(open) { }

   virtual ~G1ArchiveAllocator() {
     assert(_allocation_region == NULL, "_allocation_region not NULL");
   }

   static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h, bool open);

   // Allocate memory for an individual object.
   HeapWord* archive_mem_allocate(size_t word_size);

   // Return the memory ranges used in the current archive, after
   // aligning to the requested alignment.
   void complete_archive(GrowableArray<MemRegion>* ranges,
                         size_t end_alignment_in_bytes);

   // The number of bytes allocated by this allocator.
   size_t used() {
     return _summary_bytes_used;
   }

   // Clear the count of bytes allocated in prior G1 regions. This
   // must be done when recalculate_use is used to reset the counter
   // for the generic allocator, since it counts bytes in all G1
   // regions, including those still associated with this allocator.
   void clear_used() {
     _summary_bytes_used = 0;
   }

   // Create the _archive_region_map which is used to identify archive objects.
   static inline void enable_archive_object_check();

   // Mark regions containing the specified address range as archive/non-archive.
   static inline void set_range_archive(MemRegion range, bool open);
   static inline void clear_range_archive(MemRegion range, bool open);

   // Check if the object is in closed archive
   static inline bool is_closed_archive_object(oop object);
   // Check if the object is in open archive
   static inline bool is_open_archive_object(oop object);
   // Check if the object is either in closed archive or open archive
   static inline bool is_archive_object(oop object);

 private:
   static bool _archive_check_enabled;
   static G1ArchiveRegionMap  _closed_archive_region_map;
   static G1ArchiveRegionMap  _open_archive_region_map;

   // Check if an object is in a closed archive region using the _closed_archive_region_map.
   static inline bool in_closed_archive_range(oop object);
   // Check if an object is in open archive region using the _open_archive_region_map.
   static inline bool in_open_archive_range(oop object);

   // Check if archive object checking is enabled, to avoid calling in_open/closed_archive_range
   // unnecessarily.
   static inline bool archive_check_enabled();
 };

 #endif // SHARE_VM_GC_G1_G1ALLOCATOR_HPP
	/*
	* Copyright (c) 2014, 2018, 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_G1_G1ALLOCATOR_HPP
	#define SHARE_VM_GC_G1_G1ALLOCATOR_HPP

	#include "gc/g1/g1AllocRegion.hpp"
	#include "gc/g1/g1InCSetState.hpp"
	#include "gc/shared/collectedHeap.hpp"
	#include "gc/shared/plab.hpp"

	class EvacuationInfo;

	// Interface to keep track of which regions G1 is currently allocating into. Provides
	// some accessors (e.g. allocating into them, or getting their occupancy).
	// Also keeps track of retained regions across GCs.
	class G1Allocator : public CHeapObj<mtGC> {
	friend class VMStructs;

	private:
	G1CollectedHeap* _g1h;

	bool _survivor_is_full;
	bool _old_is_full;

	// Alloc region used to satisfy mutator allocation requests.
	MutatorAllocRegion _mutator_alloc_region;

	// Alloc region used to satisfy allocation requests by the GC for
	// survivor objects.
	SurvivorGCAllocRegion _survivor_gc_alloc_region;

	// Alloc region used to satisfy allocation requests by the GC for
	// old objects.
	OldGCAllocRegion _old_gc_alloc_region;

	HeapRegion* _retained_old_gc_alloc_region;

	bool survivor_is_full() const;
	bool old_is_full() const;

	void set_survivor_full();
	void set_old_full();

	void reuse_retained_old_region(EvacuationInfo& evacuation_info,
	OldGCAllocRegion* old,
	HeapRegion** retained);

	// Accessors to the allocation regions.
	inline MutatorAllocRegion* mutator_alloc_region();
	inline SurvivorGCAllocRegion* survivor_gc_alloc_region();
	inline OldGCAllocRegion* old_gc_alloc_region();

	// Allocation attempt during GC for a survivor object / PLAB.
	HeapWord* survivor_attempt_allocation(size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size);

	// Allocation attempt during GC for an old object / PLAB.
	HeapWord* old_attempt_allocation(size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size);
	public:
	G1Allocator(G1CollectedHeap* heap);

	#ifdef ASSERT
	// Do we currently have an active mutator region to allocate into?
	bool has_mutator_alloc_region() { return mutator_alloc_region()->get() != NULL; }
	#endif

	void init_mutator_alloc_region();
	void release_mutator_alloc_region();

	void init_gc_alloc_regions(EvacuationInfo& evacuation_info);
	void release_gc_alloc_regions(EvacuationInfo& evacuation_info);
	void abandon_gc_alloc_regions();
	bool is_retained_old_region(HeapRegion* hr);

	// Allocate blocks of memory during mutator time.

	inline HeapWord* attempt_allocation(size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size);
	inline HeapWord* attempt_allocation_locked(size_t word_size);
	inline HeapWord* attempt_allocation_force(size_t word_size);

	size_t unsafe_max_tlab_alloc();
	size_t used_in_alloc_regions();

	// Allocate blocks of memory during garbage collection. Will ensure an
	// allocation region, either by picking one or expanding the
	// heap, and then allocate a block of the given size. The block
	// may not be a humongous - it must fit into a single heap region.
	HeapWord* par_allocate_during_gc(InCSetState dest,
	size_t word_size);

	HeapWord* par_allocate_during_gc(InCSetState dest,
	size_t min_word_size,
	size_t desired_word_size,
	size_t* actual_word_size);
	};

	// Manages the PLABs used during garbage collection. Interface for allocation from PLABs.
	// Needs to handle multiple contexts, extra alignment in any "survivor" area and some
	// statistics.
	class G1PLABAllocator : public CHeapObj<mtGC> {
	friend class G1ParScanThreadState;
	private:
	G1CollectedHeap* _g1h;
	G1Allocator* _allocator;

	PLAB _surviving_alloc_buffer;
	PLAB _tenured_alloc_buffer;
	PLAB* _alloc_buffers[InCSetState::Num];

	// The survivor alignment in effect in bytes.
	// == 0 : don't align survivors
	// != 0 : align survivors to that alignment
	// These values were chosen to favor the non-alignment case since some
	// architectures have a special compare against zero instructions.
	const uint _survivor_alignment_bytes;

	// Number of words allocated directly (not counting PLAB allocation).
	size_t _direct_allocated[InCSetState::Num];

	void flush_and_retire_stats();
	inline PLAB* alloc_buffer(InCSetState dest);

	// Calculate the survivor space object alignment in bytes. Returns that or 0 if
	// there are no restrictions on survivor alignment.
	static uint calc_survivor_alignment_bytes();

	bool may_throw_away_buffer(size_t const allocation_word_sz, size_t const buffer_size) const;
	public:
	G1PLABAllocator(G1Allocator* allocator);

	void waste(size_t& wasted, size_t& undo_wasted);

	// Allocate word_sz words in dest, either directly into the regions or by
	// allocating a new PLAB. Returns the address of the allocated memory, NULL if
	// not successful. Plab_refill_failed indicates whether an attempt to refill the
	// PLAB failed or not.
	HeapWord* allocate_direct_or_new_plab(InCSetState dest,
	size_t word_sz,
	bool* plab_refill_failed);

	// Allocate word_sz words in the PLAB of dest. Returns the address of the
	// allocated memory, NULL if not successful.
	inline HeapWord* plab_allocate(InCSetState dest,
	size_t word_sz);

	inline HeapWord* allocate(InCSetState dest,
	size_t word_sz,
	bool* refill_failed);

	void undo_allocation(InCSetState dest, HeapWord* obj, size_t word_sz);
	};

	// G1ArchiveRegionMap is a boolean array used to mark G1 regions as
	// archive regions. This allows a quick check for whether an object
	// should not be marked because it is in an archive region.
	class G1ArchiveRegionMap : public G1BiasedMappedArray<bool> {
	protected:
	bool default_value() const { return false; }
	};

	// G1ArchiveAllocator is used to allocate memory in archive
	// regions. Such regions are not scavenged nor compacted by GC.
	// There are two types of archive regions, which are
	// differ in the kind of references allowed for the contained objects:
	//
	// - 'Closed' archive region contain no references outside of other
	// closed archive regions. The region is immutable by GC. GC does
	// not mark object header in 'closed' archive region.
	// - An 'open' archive region allow references to any other regions,
	// including closed archive, open archive and other java heap regions.
	// GC can adjust pointers and mark object header in 'open' archive region.
	class G1ArchiveAllocator : public CHeapObj<mtGC> {
	protected:
	bool _open; // Indicate if the region is 'open' archive.
	G1CollectedHeap* _g1h;

	// The current allocation region
	HeapRegion* _allocation_region;

	// Regions allocated for the current archive range.
	GrowableArray<HeapRegion*> _allocated_regions;

	// The number of bytes used in the current range.
	size_t _summary_bytes_used;

	// Current allocation window within the current region.
	HeapWord* _bottom;
	HeapWord* _top;
	HeapWord* _max;

	// Allocate a new region for this archive allocator.
	// Allocation is from the top of the reserved heap downward.
	bool alloc_new_region();

	public:
	G1ArchiveAllocator(G1CollectedHeap* g1h, bool open) :
	_g1h(g1h),
	_allocation_region(NULL),
	_allocated_regions((ResourceObj::set_allocation_type((address) &_allocated_regions,
	ResourceObj::C_HEAP),
	2), true /* C_Heap */),
	_summary_bytes_used(0),
	_bottom(NULL),
	_top(NULL),
	_max(NULL),
	_open(open) { }

	virtual ~G1ArchiveAllocator() {
	assert(_allocation_region == NULL, "_allocation_region not NULL");
	}

	static G1ArchiveAllocator* create_allocator(G1CollectedHeap* g1h, bool open);

	// Allocate memory for an individual object.
	HeapWord* archive_mem_allocate(size_t word_size);

	// Return the memory ranges used in the current archive, after
	// aligning to the requested alignment.
	void complete_archive(GrowableArray<MemRegion>* ranges,
	size_t end_alignment_in_bytes);

	// The number of bytes allocated by this allocator.
	size_t used() {
	return _summary_bytes_used;
	}

	// Clear the count of bytes allocated in prior G1 regions. This
	// must be done when recalculate_use is used to reset the counter
	// for the generic allocator, since it counts bytes in all G1
	// regions, including those still associated with this allocator.
	void clear_used() {
	_summary_bytes_used = 0;
	}

	// Create the _archive_region_map which is used to identify archive objects.
	static inline void enable_archive_object_check();

	// Mark regions containing the specified address range as archive/non-archive.
	static inline void set_range_archive(MemRegion range, bool open);
	static inline void clear_range_archive(MemRegion range, bool open);

	// Check if the object is in closed archive
	static inline bool is_closed_archive_object(oop object);
	// Check if the object is in open archive
	static inline bool is_open_archive_object(oop object);
	// Check if the object is either in closed archive or open archive
	static inline bool is_archive_object(oop object);

	private:
	static bool _archive_check_enabled;
	static G1ArchiveRegionMap _closed_archive_region_map;
	static G1ArchiveRegionMap _open_archive_region_map;

	// Check if an object is in a closed archive region using the _closed_archive_region_map.
	static inline bool in_closed_archive_range(oop object);
	// Check if an object is in open archive region using the _open_archive_region_map.
	static inline bool in_open_archive_range(oop object);

	// Check if archive object checking is enabled, to avoid calling in_open/closed_archive_range
	// unnecessarily.
	static inline bool archive_check_enabled();
	};

	#endif // SHARE_VM_GC_G1_G1ALLOCATOR_HPP