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https://git.code.sf.net/p/quake/quakeforge
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118 lines
3.6 KiB
C
118 lines
3.6 KiB
C
/*
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cmem.h
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Cache-line aligned memory allocator
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Copyright (C) 2020 Bill Currie <bill@taniwha.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; either version 2
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of the License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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See the GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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*/
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#ifndef __QF_cmem_h
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#define __QF_cmem_h
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#include "QF/qtypes.h"
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#define MEM_LINE_SIZE 64
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#define MAX_CACHE_LINES 9
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typedef struct memline_s {
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/* chain of free line blocks for fast allocation
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* chain begins in memsuper_t
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*/
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struct memline_s *free_next;
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struct memline_s **free_prev;
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/* chain of free line blocks within a membock for merging
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* chain begins in memblock_t
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*/
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struct memline_s *block_next;
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struct memline_s **block_prev;
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size_t size;
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/* owning block
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*/
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struct memblock_s *block;
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size_t pad[2];
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} memline_t;
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typedef struct memsline_s {
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struct memsline_s *next;
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size_t size:2;
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size_t list:4;
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size_t prev:58; // memsline_t **
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} memsline_t;
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typedef struct memblock_s {
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struct memblock_s *next;
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struct memblock_s **prev;
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/* The pointer to pass to free()
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*/
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void *mem;
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memline_t *free_lines;
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/* Size of memory region before block "header".
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*
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* Since large blocks are allocated with page-size alignment, odds are
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* high that the there will be many cache lines "wasted" in the space
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* between the address returned from aligned_alloc (to cache-line
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* alignment) and the block itself. Setting them up as a pool makes the
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* lines available for smaller allocations, thus reducing waste.
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*/
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size_t pre_size;
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/* Size of memory region after block "header".
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*
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* Will be 0 for blocks that were allocated exclusively for small
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* allocations, otherwise indicates the size of the allocated block.
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*/
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size_t post_size;
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/* True if the post-header block is free to be reused.
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*/
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int post_free;
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int pad;
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size_t pre_allocated;
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} memblock_t;
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typedef struct memsuper_s {
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size_t page_size;
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size_t page_mask;
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memblock_t *memblocks;
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/* Allocated cache lines from which smaller blocks can be allocated.
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*
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* The index is the base-2 log minus 2 of the size of the elements in the
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* cache line from which an element was last freed. Only 4-32 bytes are of
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* interest because nothing smaller than 4 bytes (int/float) will be
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* allocated, and 64 bytes and up consume entire cache lines.
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*/
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memsline_t *last_freed[4];
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/* Free chache lines grouped by size.
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*
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* The index is the base-2 log of the MINIMUM number of cache lines
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* available in each block. ie, blocks with 4, 5, 6 and 7 lines will all
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* be in the third list (index 2). For 4k page sizes, only 6 lists are
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* needed (32-63 lines) because a page can hold only 62 lines (1 for the
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* control block and one to avoid a cache-line being on a page boundary).
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* Having 9 (MAX_CACHE_LINES) lists allows page sizes up to 16kB.
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*/
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memline_t *free_lines[MAX_CACHE_LINES];
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} memsuper_t;
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memsuper_t *new_memsuper (void);
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void delete_memsuper (memsuper_t *super);
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void *cmemalloc (memsuper_t *super, size_t size);
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void cmemfree (memsuper_t *super, void *mem);
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#endif//__QF_cmem_h
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