--- old/src/hotspot/share/memory/metaspace/chunkManager.hpp 2019-08-02 08:06:35.404442390 +0200 +++ new/src/hotspot/share/memory/metaspace/chunkManager.hpp 2019-08-02 08:06:35.040441566 +0200 @@ -26,173 +26,117 @@ #define SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP #include "memory/allocation.hpp" -#include "memory/binaryTreeDictionary.hpp" -#include "memory/freeList.hpp" +#include "memory/metaspace/chunkLevel.hpp" +#include "memory/metaspace/counter.hpp" #include "memory/metaspace/metachunk.hpp" -#include "memory/metaspace/metaspaceStatistics.hpp" -#include "memory/metaspaceChunkFreeListSummary.hpp" -#include "utilities/globalDefinitions.hpp" - -class ChunkManagerTestAccessor; namespace metaspace { -typedef class FreeList ChunkList; -typedef BinaryTreeDictionary > ChunkTreeDictionary; +class VirtualSpaceList; +class ChunkManagerStatistics; -// Manages the global free lists of chunks. +// class ChunkManager +// +// The ChunkManager has a central role. Callers request chunks from it. +// It keeps the freelists for chunks. If the freelist is exhausted it +// allocates new chunks from a connected VirtualSpaceList. +// class ChunkManager : public CHeapObj { - friend class ::ChunkManagerTestAccessor; - // Free list of chunks of different sizes. - // SpecializedChunk - // SmallChunk - // MediumChunk - ChunkList _free_chunks[NumberOfFreeLists]; - - // Whether or not this is the class chunkmanager. - const bool _is_class; - - // Return non-humongous chunk list by its index. - ChunkList* free_chunks(ChunkIndex index); - - // Returns non-humongous chunk list for the given chunk word size. - ChunkList* find_free_chunks_list(size_t word_size); - - // HumongousChunk - ChunkTreeDictionary _humongous_dictionary; - - // Returns the humongous chunk dictionary. - ChunkTreeDictionary* humongous_dictionary() { return &_humongous_dictionary; } - const ChunkTreeDictionary* humongous_dictionary() const { return &_humongous_dictionary; } - - // Size, in metaspace words, of all chunks managed by this ChunkManager - size_t _free_chunks_total; - // Number of chunks in this ChunkManager - size_t _free_chunks_count; - - // Update counters after a chunk was added or removed removed. - void account_for_added_chunk(const Metachunk* c); - void account_for_removed_chunk(const Metachunk* c); - - // Given a pointer to a chunk, attempts to merge it with neighboring - // free chunks to form a bigger chunk. Returns true if successful. - bool attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type); - - // Helper for chunk merging: - // Given an address range with 1-n chunks which are all supposed to be - // free and hence currently managed by this ChunkManager, remove them - // from this ChunkManager and mark them as invalid. - // - This does not correct the occupancy map. - // - This does not adjust the counters in ChunkManager. - // - Does not adjust container count counter in containing VirtualSpaceNode. - // Returns number of chunks removed. - int remove_chunks_in_area(MetaWord* p, size_t word_size); - - // Helper for chunk splitting: given a target chunk size and a larger free chunk, - // split up the larger chunk into n smaller chunks, at least one of which should be - // the target chunk of target chunk size. The smaller chunks, including the target - // chunk, are returned to the freelist. The pointer to the target chunk is returned. - // Note that this chunk is supposed to be removed from the freelist right away. - Metachunk* split_chunk(size_t target_chunk_word_size, Metachunk* chunk); - - public: - - ChunkManager(bool is_class); - - // Add or delete (return) a chunk to the global freelist. - Metachunk* chunk_freelist_allocate(size_t word_size); - - // Map a size to a list index assuming that there are lists - // for special, small, medium, and humongous chunks. - ChunkIndex list_index(size_t size); - - // Map a given index to the chunk size. - size_t size_by_index(ChunkIndex index) const; - - bool is_class() const { return _is_class; } - - // Convenience accessors. - size_t medium_chunk_word_size() const { return size_by_index(MediumIndex); } - size_t small_chunk_word_size() const { return size_by_index(SmallIndex); } - size_t specialized_chunk_word_size() const { return size_by_index(SpecializedIndex); } - - // Take a chunk from the ChunkManager. The chunk is expected to be in - // the chunk manager (the freelist if non-humongous, the dictionary if - // humongous). - void remove_chunk(Metachunk* chunk); - - // Return a single chunk of type index to the ChunkManager. - void return_single_chunk(Metachunk* chunk); - - // Add the simple linked list of chunks to the freelist of chunks - // of type index. - void return_chunk_list(Metachunk* chunk); - - // Total of the space in the free chunks list - size_t free_chunks_total_words() const { return _free_chunks_total; } - size_t free_chunks_total_bytes() const { return free_chunks_total_words() * BytesPerWord; } - - // Number of chunks in the free chunks list - size_t free_chunks_count() const { return _free_chunks_count; } - - // Remove from a list by size. Selects list based on size of chunk. - Metachunk* free_chunks_get(size_t chunk_word_size); - -#define index_bounds_check(index) \ - assert(is_valid_chunktype(index), "Bad index: %d", (int) index) - - size_t num_free_chunks(ChunkIndex index) const { - index_bounds_check(index); - - if (index == HumongousIndex) { - return _humongous_dictionary.total_free_blocks(); - } - - ssize_t count = _free_chunks[index].count(); - return count == -1 ? 0 : (size_t) count; - } - - size_t size_free_chunks_in_bytes(ChunkIndex index) const { - index_bounds_check(index); - - size_t word_size = 0; - if (index == HumongousIndex) { - word_size = _humongous_dictionary.total_size(); - } else { - const size_t size_per_chunk_in_words = _free_chunks[index].size(); - word_size = size_per_chunk_in_words * num_free_chunks(index); - } - - return word_size * BytesPerWord; - } - - MetaspaceChunkFreeListSummary chunk_free_list_summary() const { - return MetaspaceChunkFreeListSummary(num_free_chunks(SpecializedIndex), - num_free_chunks(SmallIndex), - num_free_chunks(MediumIndex), - num_free_chunks(HumongousIndex), - size_free_chunks_in_bytes(SpecializedIndex), - size_free_chunks_in_bytes(SmallIndex), - size_free_chunks_in_bytes(MediumIndex), - size_free_chunks_in_bytes(HumongousIndex)); - } - -#ifdef ASSERT - // Debug support - // Verify free list integrity. slow=true: verify chunk-internal integrity too. - void verify(bool slow) const; - void locked_verify(bool slow) const; -#endif + // A chunk manager is connected to a virtual space list which is used + // to allocate new root chunks when no free chunks are found. + VirtualSpaceList* const _vslist; + + // Name + const char* const _name; + + // Freelist + MetachunkList _chunks [chklvl::NUM_CHUNK_LEVELS]; + + // Total size, in words, of all chunks. + SizeCounter _total_word_size; + + // Total size, in words, of the committed parts of all chunks. + SizeCounter _committed_word_size; + + // Returns true if this manager contains the given chunk. Slow (walks free list) and + // only needed for verifications. + DEBUG_ONLY(bool contains_chunk(Metachunk* metachunk) const;) + + // Given a chunk we are about to handout to the caller, make sure it is committed + // according to constants::committed_words_on_fresh_chunks. + // May fail if we hit the commit limit. + static bool commit_chunk_before_handout(Metachunk* c); + + // Return a single chunk to the freelist and adjust accounting. No merge is attempted. + void return_chunk_simple(Metachunk* c); + + // Take a single chunk from the given freelist and adjust counters. Returns NULL + // if there is no fitting chunk for this level. + Metachunk* remove_first_chunk_at_level(chklvl_t l); + + + // Given a chunk which must be outside of a freelist and must be free, split it to + // meet a target level and return it. Splinters are added to the freelist. + Metachunk* split_chunk_and_add_splinters(Metachunk* c, chklvl_t target_level); + +public: - void locked_print_free_chunks(outputStream* st); + // Creates a chunk manager with a given name (which is for debug purposes only) + // and an associated space list which will be used to request new chunks from + // (see get_chunk()) + ChunkManager(const char* name, VirtualSpaceList* space_list); - // Fill in current statistic values to the given statistics object. - void collect_statistics(ChunkManagerStatistics* out) const; + // Get a chunk and be smart about it. + // - 1) Attempt to find a free chunk of exactly the pref_level level + // - 2) Failing that, attempt to find a chunk smaller or equal the minimal level. + // - 3) Failing that, attempt to find a free chunk of larger size and split it. + // - 4) Failing that, attempt to allocate a new chunk from the connected virtual space. + // - Failing that, give up and return NULL. + // Note: this is not guaranteed to return a *committed* chunk. The chunk manager will + // attempt to commit the returned chunk according to constants::committed_words_on_fresh_chunks; + // but this may fail if we hit a commit limit. In that case, a partly uncommitted chunk + // will be returned, and the commit is attempted again when we allocate from the chunk's + // uncommitted area. See also Metachunk::allocate. + Metachunk* get_chunk(chklvl_t min_level, chklvl_t pref_level); + + // Return a single chunk to the ChunkManager and adjust accounting. May merge chunk + // with neighbors. + // Happens after a Classloader was unloaded and releases its metaspace chunks. + // !! Note: this may invalidate the chunk. Do not access the chunk after + // this function returns !! + void return_chunk(Metachunk* c); + + // Uncommit payload area of free chunks. Will be called during Metaspace GC. + void uncommit_free_chunks(); + + // Run verifications. slow=true: verify chunk-internal integrity too. + DEBUG_ONLY(void verify(bool slow) const;) + + // Returns the name of this chunk manager. + const char* name() const { return _name; } + + // Returns number of words in all free chunks. + size_t total_word_size() const { return _total_word_size.get(); } + + // Update statistics. + void add_to_statistics(ChunkManagerStatistics* out) const; + +private: + + static ChunkManager* _chunkmanager_class; + static ChunkManager* _chunkmanager_nonclass; + +public: + + static ChunkManager* chunkmanager_class() { return _chunkmanager_class; } + static ChunkManager* chunkmanager_nonclass() { return _chunkmanager_nonclass; } + + static void set_chunkmanager_class(ChunkManager* cm); + static void set_chunkmanager_nonclass(ChunkManager* cm); }; } // namespace metaspace - #endif // SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP