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Annotation of Gnu-Mach/kern/slab.h, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 2011 Free Software Foundation.
        !             3:  *
        !             4:  * This program is free software; you can redistribute it and/or modify
        !             5:  * it under the terms of the GNU General Public License as published by
        !             6:  * the Free Software Foundation; either version 2 of the License, or
        !             7:  * (at your option) any later version.
        !             8:  *
        !             9:  * This program is distributed in the hope that it will be useful,
        !            10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            12:  * GNU General Public License for more details.
        !            13:  *
        !            14:  * You should have received a copy of the GNU General Public License along
        !            15:  * with this program; if not, write to the Free Software Foundation, Inc.,
        !            16:  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
        !            17:  */
        !            18: 
        !            19: /*
        !            20:  * Copyright (c) 2010, 2011 Richard Braun.
        !            21:  * All rights reserved.
        !            22:  *
        !            23:  * Redistribution and use in source and binary forms, with or without
        !            24:  * modification, are permitted provided that the following conditions
        !            25:  * are met:
        !            26:  * 1. Redistributions of source code must retain the above copyright
        !            27:  *    notice, this list of conditions and the following disclaimer.
        !            28:  * 2. Redistributions in binary form must reproduce the above copyright
        !            29:  *    notice, this list of conditions and the following disclaimer in the
        !            30:  *    documentation and/or other materials provided with the distribution.
        !            31:  *
        !            32:  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
        !            33:  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
        !            34:  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
        !            35:  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
        !            36:  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
        !            37:  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
        !            38:  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
        !            39:  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
        !            40:  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
        !            41:  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
        !            42:  *
        !            43:  *
        !            44:  * Object caching memory allocator.
        !            45:  */
        !            46: 
        !            47: #ifndef _KERN_SLAB_H
        !            48: #define _KERN_SLAB_H
        !            49: 
        !            50: #include <kern/lock.h>
        !            51: #include <kern/list.h>
        !            52: #include <kern/rbtree.h>
        !            53: #include <mach/machine/vm_types.h>
        !            54: #include <sys/types.h>
        !            55: #include <vm/vm_types.h>
        !            56: 
        !            57: #if SLAB_USE_CPU_POOLS
        !            58: /*
        !            59:  * L1 cache line size.
        !            60:  */
        !            61: #define CPU_L1_SIZE (1 << CPU_L1_SHIFT)
        !            62: 
        !            63: /*
        !            64:  * Per-processor cache of pre-constructed objects.
        !            65:  *
        !            66:  * The flags member is a read-only CPU-local copy of the parent cache flags.
        !            67:  */
        !            68: struct kmem_cpu_pool {
        !            69:     simple_lock_data_t lock;
        !            70:     int flags;
        !            71:     int size;
        !            72:     int transfer_size;
        !            73:     int nr_objs;
        !            74:     void **array;
        !            75: } __attribute__((aligned(CPU_L1_SIZE)));
        !            76: 
        !            77: /*
        !            78:  * When a cache is created, its CPU pool type is determined from the buffer
        !            79:  * size. For small buffer sizes, many objects can be cached in a CPU pool.
        !            80:  * Conversely, for large buffer sizes, this would incur much overhead, so only
        !            81:  * a few objects are stored in a CPU pool.
        !            82:  */
        !            83: struct kmem_cpu_pool_type {
        !            84:     size_t buf_size;
        !            85:     int array_size;
        !            86:     size_t array_align;
        !            87:     struct kmem_cache *array_cache;
        !            88: };
        !            89: #endif /* SLAB_USE_CPU_POOLS */
        !            90: 
        !            91: /*
        !            92:  * Buffer descriptor.
        !            93:  *
        !            94:  * For normal caches (i.e. without SLAB_CF_VERIFY), bufctls are located at the
        !            95:  * end of (but inside) each buffer. If SLAB_CF_VERIFY is set, bufctls are
        !            96:  * located after each buffer.
        !            97:  *
        !            98:  * When an object is allocated to a client, its bufctl isn't used. This memory
        !            99:  * is instead used for redzoning if cache debugging is in effect.
        !           100:  */
        !           101: union kmem_bufctl {
        !           102:     union kmem_bufctl *next;
        !           103:     unsigned long redzone;
        !           104: };
        !           105: 
        !           106: /*
        !           107:  * Buffer tag.
        !           108:  *
        !           109:  * This structure is only used for SLAB_CF_VERIFY caches. It is located after
        !           110:  * the bufctl and includes information about the state of the buffer it
        !           111:  * describes (allocated or not). It should be thought of as a debugging
        !           112:  * extension of the bufctl.
        !           113:  */
        !           114: struct kmem_buftag {
        !           115:     unsigned long state;
        !           116: };
        !           117: 
        !           118: /*
        !           119:  * Page-aligned collection of unconstructed buffers.
        !           120:  */
        !           121: struct kmem_slab {
        !           122:     struct list list_node;
        !           123:     struct rbtree_node tree_node;
        !           124:     unsigned long nr_refs;
        !           125:     union kmem_bufctl *first_free;
        !           126:     void *addr;
        !           127: };
        !           128: 
        !           129: /*
        !           130:  * Type for constructor functions.
        !           131:  *
        !           132:  * The pre-constructed state of an object is supposed to include only
        !           133:  * elements such as e.g. linked lists, locks, reference counters. Therefore
        !           134:  * constructors are expected to 1) never fail and 2) not need any
        !           135:  * user-provided data. The first constraint implies that object construction
        !           136:  * never performs dynamic resource allocation, which also means there is no
        !           137:  * need for destructors.
        !           138:  */
        !           139: typedef void (*kmem_cache_ctor_t)(void *obj);
        !           140: 
        !           141: /*
        !           142:  * Types for slab allocation/free functions.
        !           143:  *
        !           144:  * All addresses and sizes must be page-aligned.
        !           145:  */
        !           146: typedef vm_offset_t (*kmem_slab_alloc_fn_t)(vm_size_t);
        !           147: typedef void (*kmem_slab_free_fn_t)(vm_offset_t, vm_size_t);
        !           148: 
        !           149: /*
        !           150:  * Cache name buffer size.
        !           151:  */
        !           152: #define KMEM_CACHE_NAME_SIZE 32
        !           153: 
        !           154: /*
        !           155:  * Cache of objects.
        !           156:  *
        !           157:  * Locking order : cpu_pool -> cache. CPU pools locking is ordered by CPU ID.
        !           158:  */
        !           159: struct kmem_cache {
        !           160: #if SLAB_USE_CPU_POOLS
        !           161:     /* CPU pool layer */
        !           162:     struct kmem_cpu_pool cpu_pools[NCPUS];
        !           163:     struct kmem_cpu_pool_type *cpu_pool_type;
        !           164: #endif /* SLAB_USE_CPU_POOLS */
        !           165: 
        !           166:     /* Slab layer */
        !           167:     simple_lock_data_t lock;
        !           168:     struct list node;   /* Cache list linkage */
        !           169:     struct list partial_slabs;
        !           170:     struct list free_slabs;
        !           171:     struct rbtree active_slabs;
        !           172:     int flags;
        !           173:     size_t obj_size;    /* User-provided size */
        !           174:     size_t align;
        !           175:     size_t buf_size;    /* Aligned object size  */
        !           176:     size_t bufctl_dist; /* Distance from buffer to bufctl   */
        !           177:     size_t slab_size;
        !           178:     size_t color;
        !           179:     size_t color_max;
        !           180:     unsigned long bufs_per_slab;
        !           181:     unsigned long nr_objs;  /* Number of allocated objects */
        !           182:     unsigned long nr_bufs;  /* Total number of buffers */
        !           183:     unsigned long nr_slabs;
        !           184:     unsigned long nr_free_slabs;
        !           185:     kmem_cache_ctor_t ctor;
        !           186:     kmem_slab_alloc_fn_t slab_alloc_fn;
        !           187:     kmem_slab_free_fn_t slab_free_fn;
        !           188:     char name[KMEM_CACHE_NAME_SIZE];
        !           189:     size_t buftag_dist; /* Distance from buffer to buftag */
        !           190:     size_t redzone_pad; /* Bytes from end of object to redzone word */
        !           191: };
        !           192: 
        !           193: /*
        !           194:  * Mach-style declarations for struct kmem_cache.
        !           195:  */
        !           196: typedef struct kmem_cache *kmem_cache_t;
        !           197: #define KMEM_CACHE_NULL ((kmem_cache_t) 0)
        !           198: 
        !           199: /*
        !           200:  * VM submap for slab allocations.
        !           201:  */
        !           202: extern vm_map_t kmem_map;
        !           203: 
        !           204: /*
        !           205:  * Cache initialization flags.
        !           206:  */
        !           207: #define KMEM_CACHE_NOCPUPOOL    0x1 /* Don't use the per-cpu pools */
        !           208: #define KMEM_CACHE_NOOFFSLAB    0x2 /* Don't allocate external slab data */
        !           209: #define KMEM_CACHE_NORECLAIM    0x4 /* Never give slabs back to their source,
        !           210:                                        implies KMEM_CACHE_NOOFFSLAB */
        !           211: #define KMEM_CACHE_VERIFY       0x8 /* Use debugging facilities */
        !           212: 
        !           213: /*
        !           214:  * Initialize a cache.
        !           215:  */
        !           216: void kmem_cache_init(struct kmem_cache *cache, const char *name,
        !           217:                      size_t obj_size, size_t align, kmem_cache_ctor_t ctor,
        !           218:                      kmem_slab_alloc_fn_t slab_alloc_fn,
        !           219:                      kmem_slab_free_fn_t slab_free_fn, int flags);
        !           220: 
        !           221: /*
        !           222:  * Allocate an object from a cache.
        !           223:  */
        !           224: vm_offset_t kmem_cache_alloc(struct kmem_cache *cache);
        !           225: 
        !           226: /*
        !           227:  * Release an object to its cache.
        !           228:  */
        !           229: void kmem_cache_free(struct kmem_cache *cache, vm_offset_t obj);
        !           230: 
        !           231: /*
        !           232:  * Initialize the memory allocator module.
        !           233:  */
        !           234: void slab_bootstrap(void);
        !           235: void slab_init(void);
        !           236: 
        !           237: /*
        !           238:  * Release free slabs to the VM system.
        !           239:  */
        !           240: void slab_collect(void);
        !           241: 
        !           242: /*
        !           243:  * Display a summary of all kernel caches.
        !           244:  */
        !           245: void slab_info(void);
        !           246: 
        !           247: #endif /* _KERN_SLAB_H */

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