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Diffstat (limited to 'kern/slab_i.h')
| -rw-r--r-- | kern/slab_i.h | 220 |
1 files changed, 220 insertions, 0 deletions
diff --git a/kern/slab_i.h b/kern/slab_i.h new file mode 100644 index 0000000..a609efb --- /dev/null +++ b/kern/slab_i.h @@ -0,0 +1,220 @@ +/* + * Copyright (c) 2010, 2011, 2012, 2013 Richard Braun. + * + * 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 3 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, see <http://www.gnu.org/licenses/>. + */ + +#ifndef _KERN_KMEM_I_H +#define _KERN_KMEM_I_H + +#include <kern/list.h> +#include <kern/lock.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; +} __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 KMEM_CF_VERIFY), bufctls are located at the + * end of (but inside) each buffer. If KMEM_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; +}; + +/* + * Redzone guard word. + */ +#ifdef __LP64__ +#ifdef _HOST_BIG_ENDIAN +#define KMEM_REDZONE_WORD 0xfeedfacefeedfaceUL +#else /* _HOST_BIG_ENDIAN */ +#define KMEM_REDZONE_WORD 0xcefaedfecefaedfeUL +#endif /* _HOST_BIG_ENDIAN */ +#else /* __LP64__ */ +#ifdef _HOST_BIG_ENDIAN +#define KMEM_REDZONE_WORD 0xfeedfaceUL +#else /* _HOST_BIG_ENDIAN */ +#define KMEM_REDZONE_WORD 0xcefaedfeUL +#endif /* _HOST_BIG_ENDIAN */ +#endif /* __LP64__ */ + +/* + * Redzone byte for padding. + */ +#define KMEM_REDZONE_BYTE 0xbb + +/* + * Buffer tag. + * + * This structure is only used for KMEM_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; +}; + +/* + * Values the buftag state member can take. + */ +#ifdef __LP64__ +#ifdef _HOST_BIG_ENDIAN +#define KMEM_BUFTAG_ALLOC 0xa110c8eda110c8edUL +#define KMEM_BUFTAG_FREE 0xf4eeb10cf4eeb10cUL +#else /* _HOST_BIG_ENDIAN */ +#define KMEM_BUFTAG_ALLOC 0xedc810a1edc810a1UL +#define KMEM_BUFTAG_FREE 0x0cb1eef40cb1eef4UL +#endif /* _HOST_BIG_ENDIAN */ +#else /* __LP64__ */ +#ifdef _HOST_BIG_ENDIAN +#define KMEM_BUFTAG_ALLOC 0xa110c8edUL +#define KMEM_BUFTAG_FREE 0xf4eeb10cUL +#else /* _HOST_BIG_ENDIAN */ +#define KMEM_BUFTAG_ALLOC 0xedc810a1UL +#define KMEM_BUFTAG_FREE 0x0cb1eef4UL +#endif /* _HOST_BIG_ENDIAN */ +#endif /* __LP64__ */ + +/* + * Free and uninitialized patterns. + * + * These values are unconditionnally 64-bit wide since buffers are at least + * 8-byte aligned. + */ +#ifdef _HOST_BIG_ENDIAN +#define KMEM_FREE_PATTERN 0xdeadbeefdeadbeefULL +#define KMEM_UNINIT_PATTERN 0xbaddcafebaddcafeULL +#else /* _HOST_BIG_ENDIAN */ +#define KMEM_FREE_PATTERN 0xefbeaddeefbeaddeULL +#define KMEM_UNINIT_PATTERN 0xfecaddbafecaddbaULL +#endif /* _HOST_BIG_ENDIAN */ + +/* + * Page-aligned collection of unconstructed buffers. + * + * This structure is either allocated from the slab cache, or, when internal + * fragmentation allows it, or if forced by the cache creator, from the slab + * it describes. + */ +struct kmem_slab { + struct list node; + unsigned long nr_refs; + union kmem_bufctl *first_free; + void *addr; +}; + +/* + * Cache name buffer size. The size is chosen so that struct + * kmem_cache fits into two cache lines. The size of a cache line on + * a typical CPU is 64 bytes. + */ +#define KMEM_CACHE_NAME_SIZE 24 + +/* + * Cache flags. + * + * The flags don't change once set and can be tested without locking. + */ +#define KMEM_CF_NO_CPU_POOL 0x1 /* CPU pool layer disabled */ +#define KMEM_CF_SLAB_EXTERNAL 0x2 /* Slab data is off slab */ +#define KMEM_CF_VERIFY 0x4 /* Debugging facilities enabled */ +#define KMEM_CF_DIRECT 0x8 /* Quick buf-to-slab lookup */ + +/* + * Cache of objects. + * + * Locking order : cpu_pool -> cache. CPU pools locking is ordered by CPU ID. + * + * The partial slabs list is sorted by slab references. Slabs with a high + * number of references are placed first on the list to reduce fragmentation. + * Sorting occurs at insertion/removal of buffers in a slab. As the list + * is maintained sorted, and the number of references only changes by one, + * this is a very cheap operation in the average case and the worst (linear) + * case is very unlikely. + */ +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; + int flags; + size_t bufctl_dist; /* Distance from buffer to bufctl */ + size_t slab_size; + unsigned long bufs_per_slab; + unsigned long nr_objs; /* Number of allocated objects */ + unsigned long nr_free_slabs; + kmem_cache_ctor_t ctor; + /* All fields below are cold */ + size_t obj_size; /* User-provided size */ + /* Assuming ! SLAB_USE_CPU_POOLS, here is the cacheline boundary */ + size_t align; + size_t buf_size; /* Aligned object size */ + size_t color; + size_t color_max; + unsigned long nr_bufs; /* Total number of buffers */ + unsigned long nr_slabs; + 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 */ +} __cacheline_aligned; + +#endif /* _KERN_KMEM_I_H */ |