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/*
* Copyright (c) 2011 Free Software Foundation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* Copyright (c) 2010, 2011 Richard Braun.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* Object caching memory allocator.
*/
#ifndef _KERN_SLAB_H
#define _KERN_SLAB_H
#include <kern/lock.h>
#include <kern/list.h>
#include <kern/rbtree.h>
#include <mach/machine/vm_types.h>
#include <sys/types.h>
#include <vm/vm_types.h>
#if SLAB_USE_CPU_POOLS
/*
* L1 cache line size.
*/
#define CPU_L1_SIZE (1 << CPU_L1_SHIFT)
/*
* Per-processor cache of pre-constructed objects.
*
* The flags member is a read-only CPU-local copy of the parent cache flags.
*/
struct kmem_cpu_pool {
simple_lock_data_t lock;
int flags;
int size;
int transfer_size;
int nr_objs;
void **array;
} __attribute__((aligned(CPU_L1_SIZE)));
/*
* When a cache is created, its CPU pool type is determined from the buffer
* size. For small buffer sizes, many objects can be cached in a CPU pool.
* Conversely, for large buffer sizes, this would incur much overhead, so only
* a few objects are stored in a CPU pool.
*/
struct kmem_cpu_pool_type {
size_t buf_size;
int array_size;
size_t array_align;
struct kmem_cache *array_cache;
};
#endif /* SLAB_USE_CPU_POOLS */
/*
* Buffer descriptor.
*
* For normal caches (i.e. without SLAB_CF_VERIFY), bufctls are located at the
* end of (but inside) each buffer. If SLAB_CF_VERIFY is set, bufctls are
* located after each buffer.
*
* When an object is allocated to a client, its bufctl isn't used. This memory
* is instead used for redzoning if cache debugging is in effect.
*/
union kmem_bufctl {
union kmem_bufctl *next;
unsigned long redzone;
};
/*
* Buffer tag.
*
* This structure is only used for SLAB_CF_VERIFY caches. It is located after
* the bufctl and includes information about the state of the buffer it
* describes (allocated or not). It should be thought of as a debugging
* extension of the bufctl.
*/
struct kmem_buftag {
unsigned long state;
};
/*
* Page-aligned collection of unconstructed buffers.
*/
struct kmem_slab {
struct list list_node;
struct rbtree_node tree_node;
unsigned long nr_refs;
union kmem_bufctl *first_free;
void *addr;
};
/*
* Type for constructor functions.
*
* The pre-constructed state of an object is supposed to include only
* elements such as e.g. linked lists, locks, reference counters. Therefore
* constructors are expected to 1) never fail and 2) not need any
* user-provided data. The first constraint implies that object construction
* never performs dynamic resource allocation, which also means there is no
* need for destructors.
*/
typedef void (*kmem_cache_ctor_t)(void *obj);
/*
* Types for slab allocation/free functions.
*
* All addresses and sizes must be page-aligned.
*/
typedef vm_offset_t (*kmem_slab_alloc_fn_t)(vm_size_t);
typedef void (*kmem_slab_free_fn_t)(vm_offset_t, vm_size_t);
/*
* Cache name buffer size.
*/
#define KMEM_CACHE_NAME_SIZE 24
/*
* Cache of objects.
*
* Locking order : cpu_pool -> cache. CPU pools locking is ordered by CPU ID.
*/
struct kmem_cache {
#if SLAB_USE_CPU_POOLS
/* CPU pool layer */
struct kmem_cpu_pool cpu_pools[NCPUS];
struct kmem_cpu_pool_type *cpu_pool_type;
#endif /* SLAB_USE_CPU_POOLS */
/* Slab layer */
simple_lock_data_t lock;
struct list node; /* Cache list linkage */
struct list partial_slabs;
struct list free_slabs;
struct rbtree active_slabs;
int flags;
size_t obj_size; /* User-provided size */
size_t align;
size_t buf_size; /* Aligned object size */
size_t bufctl_dist; /* Distance from buffer to bufctl */
size_t slab_size;
size_t color;
size_t color_max;
unsigned long bufs_per_slab;
unsigned long nr_objs; /* Number of allocated objects */
unsigned long nr_bufs; /* Total number of buffers */
unsigned long nr_slabs;
unsigned long nr_free_slabs;
kmem_cache_ctor_t ctor;
kmem_slab_alloc_fn_t slab_alloc_fn;
kmem_slab_free_fn_t slab_free_fn;
char name[KMEM_CACHE_NAME_SIZE];
size_t buftag_dist; /* Distance from buffer to buftag */
size_t redzone_pad; /* Bytes from end of object to redzone word */
};
/*
* Mach-style declarations for struct kmem_cache.
*/
typedef struct kmem_cache *kmem_cache_t;
#define KMEM_CACHE_NULL ((kmem_cache_t) 0)
/*
* VM submap for slab allocations.
*/
extern vm_map_t kmem_map;
/*
* Cache initialization flags.
*/
#define KMEM_CACHE_NOCPUPOOL 0x1 /* Don't use the per-cpu pools */
#define KMEM_CACHE_NOOFFSLAB 0x2 /* Don't allocate external slab data */
#define KMEM_CACHE_NORECLAIM 0x4 /* Never give slabs back to their source,
implies KMEM_CACHE_NOOFFSLAB */
#define KMEM_CACHE_VERIFY 0x8 /* Use debugging facilities */
/*
* Initialize a cache.
*/
void kmem_cache_init(struct kmem_cache *cache, const char *name,
size_t obj_size, size_t align, kmem_cache_ctor_t ctor,
kmem_slab_alloc_fn_t slab_alloc_fn,
kmem_slab_free_fn_t slab_free_fn, int flags);
/*
* Allocate an object from a cache.
*/
vm_offset_t kmem_cache_alloc(struct kmem_cache *cache);
/*
* Release an object to its cache.
*/
void kmem_cache_free(struct kmem_cache *cache, vm_offset_t obj);
/*
* Initialize the memory allocator module.
*/
void slab_bootstrap(void);
void slab_init(void);
/*
* Release free slabs to the VM system.
*/
void slab_collect(void);
/*
* Display a summary of all kernel caches.
*/
void slab_info(void);
#endif /* _KERN_SLAB_H */
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