--- old/src/hotspot/share/memory/metaspace/virtualSpaceNode.hpp 2020-09-04 13:58:40.593698236 +0200 +++ /dev/null 2020-09-04 12:37:41.765504620 +0200 @@ -1,293 +0,0 @@ -/* - * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved. - * Copyright (c) 2018, 2020 SAP SE. 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_MEMORY_METASPACE_VIRTUALSPACENODE_HPP -#define SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP - - -#include "memory/allocation.hpp" -#include "memory/metaspace/counter.hpp" -#include "memory/metaspace/commitMask.hpp" -#include "memory/metaspace/rootChunkArea.hpp" -#include "memory/metaspace/settings.hpp" -#include "memory/memRegion.hpp" -#include "memory/virtualspace.hpp" -#include "utilities/debug.hpp" -#include "utilities/bitMap.hpp" -#include "utilities/globalDefinitions.hpp" - - -class outputStream; - -namespace metaspace { - -class CommitLimiter; -class FreeChunkListVector; - -// VirtualSpaceNode manages a single contiguous address range of metaspace. Logically that memory -// region is split up into a sequence of "root chunk areas", each one containing one root chunk -// or splinters of a root chunk. -// -// The underlying memory is also logically divided into a number of "commit granules", units of memory -// which may be committed or uncommitted independently from each other. -// -// (Both root chunk areas and commit granules have not much to do with each other - one is a way to -// reserve memory for the upper regions, see ChunkManager. One is a way to manage commited memory.) -// -// VirtualSpaceNode: -// - exposes a function to allocate a new root chunk (see VirtualSpaceNode::allocate_root_chunk()). -// -// - knows about the commit state of the memory region - which commit granule are committed, which -// are not. It exposes functions to commit and uncommit regions (without actively committing -// itself) -// -// - It has a reference to a "CommitLimiter", an interface to query whether committing is -// possible. That interface hides the various ways committing may be limited (GC threshold, -// MaxMetaspaceSize, ...) -// -// - It uses ReservedSpace to reserve its memory. It either owns the ReservedSpace or that -// space got handed in from outside (ccs). -// -// -// -// -// | root chunk area | root chunk area | root chunk area | <-- root chunk areas -// -// +-----------------------------------------------------------------------------------------------+ -// | | -// | `VirtualSpaceNode` memory | -// | | -// +-----------------------------------------------------------------------------------------------+ -// -// |x| |x|x|x| | | | |x|x|x| | | |x|x| | | |x|x|x|x| | | | | | | | |x| | | |x|x|x|x| | | |x| | | |x| <-- commit granules -// -// (x = committed) -// - -class VirtualSpaceNode : public CHeapObj { - - // Link to next VirtualSpaceNode - VirtualSpaceNode* _next; - - // The underlying space. This has been either created by this node - // and is owned by it, or has been handed in from outside (e.g. in - // case of CompressedClassSpace). - ReservedSpace _rs; - - // True if the node owns the reserved space, false if not. - const bool _owns_rs; - - // Start pointer of the area. - MetaWord* const _base; - - // Size, in words, of the whole node - const size_t _word_size; - - // Size, in words, of the range of this node which has been handed out in - // the form of root chunks. - size_t _used_words; - - // The bitmap describing the commit state of the region: - // Each bit covers a region of 64K (see constants::commit_granule_size). - CommitMask _commit_mask; - - // An array/lookup table of RootChunkArea objects. Each one describes a root chunk area. - RootChunkAreaLUT _root_chunk_area_lut; - - // Limiter object to ask before expanding the committed size of this node. - CommitLimiter* const _commit_limiter; - - // Points to outside size counters which we are to increase/decrease when we commit/uncommit - // space from this node. - SizeCounter* const _total_reserved_words_counter; - SizeCounter* const _total_committed_words_counter; - - /// committing, uncommitting /// - - // Given a pointer into this node, calculate the start of the commit granule - // the pointer points into. - MetaWord* calc_start_of_granule(MetaWord* p) const { - DEBUG_ONLY(check_pointer(p)); - return align_down(p, Settings::commit_granule_bytes()); - } - - // Given an address range, ensure it is committed. - // - // The range has to be aligned to granule size. - // - // Function will: - // - check how many granules in that region are uncommitted; If all are committed, it - // returns true immediately. - // - check if committing those uncommitted granules would bring us over the commit limit - // (GC threshold, MaxMetaspaceSize). If true, it returns false. - // - commit the memory. - // - mark the range as committed in the commit mask - // - // Returns true if success, false if it did hit a commit limit. - bool commit_range(MetaWord* p, size_t word_size); - - //// creation //// - - // Create a new empty node spanning the given given reserved space. - VirtualSpaceNode(ReservedSpace rs, bool owns_rs, CommitLimiter* limiter, - SizeCounter* reserve_counter, SizeCounter* commit_counter); - -public: - - // Create a node of a given size (it will create its own space). - static VirtualSpaceNode* create_node(size_t word_size, CommitLimiter* limiter, SizeCounter* reserve_words_counter, - SizeCounter* commit_words_counter); - - // Create a node over an existing space - static VirtualSpaceNode* create_node(ReservedSpace rs, CommitLimiter* limiter, SizeCounter* reserve_words_counter, - SizeCounter* commit_words_counter); - - ~VirtualSpaceNode(); - - // Note: public for gtests only, could be private. - MetaWord* base() const { return _base; } - - // Reserved size of the whole node. - size_t word_size() const { return _word_size; } - - //// Chunk allocation, splitting, merging ///// - - // Allocate a root chunk from this node. Will fail and return NULL if the node is full - // - if we used up the whole address space of this node's memory region. - // (in case this node backs compressed class space, this is how we hit - // CompressedClassSpaceSize). - // Note that this just returns reserved memory; caller must take care of committing this - // chunk before using it. - Metachunk* allocate_root_chunk(); - - // Given a chunk c, split it recursively until you get a chunk of the given target_level. - // - // The resulting target chunk resides at the same address as the original chunk. - // The resulting splinters are added to freelists. - void split(chunklevel_t target_level, Metachunk* c, FreeChunkListVector* freelists); - - // Given a chunk, attempt to merge it recursively with its neighboring chunks. - // - // If successful (merged at least once), returns address of - // the merged chunk; NULL otherwise. - // - // The merged chunks are removed from the freelists. - // - // !!! Please note that if this method returns a non-NULL value, the - // original chunk will be invalid and should not be accessed anymore! !!! - Metachunk* merge(Metachunk* c, FreeChunkListVector* freelists); - - // Given a chunk c, which must be "in use" and must not be a root chunk, attempt to - // enlarge it in place by claiming its trailing buddy. - // - // This will only work if c is the leader of the buddy pair and the trailing buddy is free. - // - // If successful, the follower chunk will be removed from the freelists, the leader chunk c will - // double in size (level decreased by one). - // - // On success, true is returned, false otherwise. - bool attempt_enlarge_chunk(Metachunk* c, FreeChunkListVector* freelists); - - // Attempts to purge the node: - // - // If all chunks living in this node are free, they will all be removed from - // the freelist they currently reside in. Then, the node will be deleted. - // - // Returns true if the node has been deleted, false if not. - // !! If this returns true, do not access the node from this point on. !! - bool attempt_purge(FreeChunkListVector* freelists); - - // Attempts to uncommit free areas according to the rules set in settings. - // Returns number of words uncommitted. - size_t uncommit_free_areas(); - - /// misc ///// - - // Returns size, in words, of the used space in this node alone. - // (Notes: - // - This is the space handed out to the ChunkManager, so it is "used" from the viewpoint of this node, - // but not necessarily used for Metadata. - // - This may or may not be committed memory. - size_t used_words() const { return _used_words; } - - // Returns size, in words, of how much space is left in this node alone. - size_t free_words() const { return _word_size - _used_words; } - - // Returns size, in words, of committed space in this node alone. - // Note: iterates over commit mask and hence may be a tad expensive on large nodes. - size_t committed_words() const; - - //// Committing/uncommitting memory ///// - - // Given an address range, ensure it is committed. - // - // The range does not have to be aligned to granule size. However, the function will always commit - // whole granules. - // - // Function will: - // - check how many granules in that region are uncommitted; If all are committed, it - // returns true immediately. - // - check if committing those uncommitted granules would bring us over the commit limit - // (GC threshold, MaxMetaspaceSize). If true, it returns false. - // - commit the memory. - // - mark the range as committed in the commit mask - // - // Returns true if success, false if it did hit a commit limit. - bool ensure_range_is_committed(MetaWord* p, size_t word_size); - - // Given an address range (which has to be aligned to commit granule size): - // - uncommit it - // - mark it as uncommitted in the commit mask - void uncommit_range(MetaWord* p, size_t word_size); - - //// List stuff //// - VirtualSpaceNode* next() const { return _next; } - void set_next(VirtualSpaceNode* vsn) { _next = vsn; } - - - /// Debug stuff //// - - // Print a description about this node. - void print_on(outputStream* st) const; - - // Verify counters and basic structure. Slow mode: verify all chunks in depth - bool contains(const MetaWord* p) const { - return p >= _base && p < _base + _used_words; - } - -#ifdef ASSERT - void check_pointer(const MetaWord* p) const { - assert(contains(p), "invalid pointer"); - } - void verify(bool slow) const; - void verify_locked(bool slow) const; -#endif - -}; - - -} // namespace metaspace - -#endif // SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP