From e6918187568dbd01842d8d1d2c808ce16a894239 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 21 Apr 2024 13:54:28 +0200 Subject: Adding upstream version 18.2.2. Signed-off-by: Daniel Baumann --- .../lock/range/range_tree/lib/util/memarena.h | 141 +++++++++++++++++++++ 1 file changed, 141 insertions(+) create mode 100644 src/rocksdb/utilities/transactions/lock/range/range_tree/lib/util/memarena.h (limited to 'src/rocksdb/utilities/transactions/lock/range/range_tree/lib/util/memarena.h') diff --git a/src/rocksdb/utilities/transactions/lock/range/range_tree/lib/util/memarena.h b/src/rocksdb/utilities/transactions/lock/range/range_tree/lib/util/memarena.h new file mode 100644 index 000000000..ddcc1144f --- /dev/null +++ b/src/rocksdb/utilities/transactions/lock/range/range_tree/lib/util/memarena.h @@ -0,0 +1,141 @@ +/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ +// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4: +#ident "$Id$" +/*====== +This file is part of PerconaFT. + + +Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved. + + PerconaFT is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License, version 2, + as published by the Free Software Foundation. + + PerconaFT 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 for more details. + + You should have received a copy of the GNU General Public License + along with PerconaFT. If not, see . + +---------------------------------------- + + PerconaFT is free software: you can redistribute it and/or modify + it under the terms of the GNU Affero General Public License, version 3, + as published by the Free Software Foundation. + + PerconaFT 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 Affero General Public License for more details. + + You should have received a copy of the GNU Affero General Public License + along with PerconaFT. If not, see . + +---------------------------------------- + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. +======= */ + +#ident \ + "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved." + +#pragma once + +#include + +/* + * A memarena is used to efficiently store a collection of objects that never + * move The pattern is allocate more and more stuff and free all of the items at + * once. The underlying memory will store 1 or more objects per chunk. Each + * chunk is contiguously laid out in memory but chunks are not necessarily + * contiguous with each other. + */ +class memarena { + public: + memarena() + : _current_chunk(arena_chunk()), + _other_chunks(nullptr), + _n_other_chunks(0), + _size_of_other_chunks(0), + _footprint_of_other_chunks(0) {} + + // Effect: Create a memarena with the specified initial size + void create(size_t initial_size); + + void destroy(void); + + // Effect: Allocate some memory. The returned value remains valid until the + // memarena is cleared or closed. + // In case of ENOMEM, aborts. + void *malloc_from_arena(size_t size); + + // Effect: Move all the memory from this memarena into DEST. + // When SOURCE is closed the memory won't be freed. + // When DEST is closed, the memory will be freed, unless DEST moves + // its memory to another memarena... + void move_memory(memarena *dest); + + // Effect: Calculate the amount of memory used by a memory arena. + size_t total_memory_size(void) const; + + // Effect: Calculate the used space of the memory arena (ie: excludes unused + // space) + size_t total_size_in_use(void) const; + + // Effect: Calculate the amount of memory used, according to + // toku_memory_footprint(), + // which is a more expensive but more accurate count of memory used. + size_t total_footprint(void) const; + + // iterator over the underlying chunks that store objects in the memarena. + // a chunk is represented by a pointer to const memory and a usable byte + // count. + class chunk_iterator { + public: + chunk_iterator(const memarena *ma) : _ma(ma), _chunk_idx(-1) {} + + // returns: base pointer to the current chunk + // *used set to the number of usable bytes + // if more() is false, returns nullptr and *used = 0 + const void *current(size_t *used) const; + + // requires: more() is true + void next(); + + bool more() const; + + private: + // -1 represents the 'initial' chunk in a memarena, ie: ma->_current_chunk + // >= 0 represents the i'th chunk in the ma->_other_chunks array + const memarena *_ma; + int _chunk_idx; + }; + + private: + struct arena_chunk { + arena_chunk() : buf(nullptr), used(0), size(0) {} + char *buf; + size_t used; + size_t size; + }; + + struct arena_chunk _current_chunk; + struct arena_chunk *_other_chunks; + int _n_other_chunks; + size_t _size_of_other_chunks; // the buf_size of all the other chunks. + size_t _footprint_of_other_chunks; // the footprint of all the other chunks. + + friend class memarena_unit_test; +}; -- cgit v1.2.3