Initial changes for new metaspace. Only tested for Linux x64.
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#ifndef SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
#define SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
#include "memory/allocation.hpp"
#include "memory/metaspace.hpp"
#include "memory/metaspace/blockFreelist.hpp"
#include "memory/metaspace/chunkAllocSequence.hpp"
#include "memory/metaspace/chunkManager.hpp"
#include "memory/metaspace/metachunk.hpp"
#include "memory/metaspace/metaspaceCommon.hpp"
class outputStream;
class Mutex;
namespace metaspace {
class sm_stats_t;
// The SpaceManager:
// - keeps a list of chunks-in-use by the class loader, as well as a current chunk used
// to allocate from
// - keeps a dictionary of free MetaBlocks. Those can be remnants of a retired chunk or
// allocations which were not needed anymore for some reason (e.g. releasing half-allocated
// structures when class loading fails)
class SpaceManager : public CHeapObj<mtClass> {
// Lock handed down from the associated ClassLoaderData.
// Protects allocations from this space.
Mutex* const _lock;
// The chunk manager to allocate chunks from.
ChunkManager* const _chunk_manager;
// The chunk allocation strategy to use.
const ChunkAllocSequence* const _chunk_alloc_sequence;
// List of chunks in use by this SpaceManager. Allocations
// are done from the current chunk. The list is used for deallocating
// chunks when the SpaceManager is freed.
MetachunkList _chunks;
Metachunk* current_chunk() { return _chunks.first(); }
const Metachunk* current_chunk() const { return _chunks.first(); }
// Prematurely released metablocks.
BlockFreelist* _block_freelist;
// Points to outside size counter which we are to increase/decrease when we allocate memory
// on behalf of a user or when we are destroyed.
SizeAtomicCounter* const _total_used_words_counter;
const char* const _name;
Mutex* lock() const { return _lock; }
ChunkManager* chunk_manager() const { return _chunk_manager; }
const ChunkAllocSequence* chunk_alloc_sequence() const { return _chunk_alloc_sequence; }
BlockFreelist* block_freelist() const { return _block_freelist; }
void create_block_freelist();
void add_allocation_to_block_freelist(MetaWord* p, size_t word_size);
// The current chunk is too small to service an allocation request, and we cannot enlarge
// it in-place. Before we allocate a new chunk, take care of the remaining space in the
// current chunk by storing it in the deallocation freelist.
void retire_current_chunk();
// Given a requested word size, will allocate a chunk large enough to at least fit that
// size, but may be larger according to the rules in the ChunkAllocSequence.
// Updates counters and adds the chunk to the head of the chunk list.
Metachunk* allocate_chunk_to_fit(size_t requested_word_size);
// Prematurely returns a metaspace allocation to the _block_freelists
// because it is not needed anymore (requires CLD lock to be active).
void deallocate_locked(MetaWord* p, size_t word_size);
// Returns true if the area indicated by pointer and size have actually been allocated
// from this space manager.
DEBUG_ONLY(bool is_valid_area(MetaWord* p, size_t word_size) const;)
public:
SpaceManager(ChunkManager* chunk_manager,
const ChunkAllocSequence* alloc_sequence,
Mutex* lock,
SizeAtomicCounter* total_used_words_counter,
const char* name);
~SpaceManager();
// Allocate memory from Metaspace.
// 1) Attempt to allocate from the dictionary of deallocated blocks.
// 2) Attempt to allocate from the current chunk.
// 3) Attempt to enlarge the current chunk in place if it is too small.
// 4) Attempt to get a new chunk and allocate from that chunk.
// At any point, if we hit a commit limit, we return NULL.
MetaWord* allocate(size_t word_size);
// Prematurely returns a metaspace allocation to the _block_freelists because it is not
// needed anymore.
void deallocate(MetaWord* p, size_t word_size);
// Update statistics. This walks all in-use chunks.
void add_to_statistics(sm_stats_t* out) const;
// Run verifications. slow=true: verify chunk-internal integrity too.
DEBUG_ONLY(void verify(bool slow) const;)
};
} // namespace metaspace
#endif // SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP