332 lines
10 KiB
C
332 lines
10 KiB
C
/*
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* Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
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*
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* (C) SGI 2006, Christoph Lameter
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* Cleaned up and restructured to ease the addition of alternative
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* implementations of SLAB allocators.
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*/
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#ifndef _LINUX_SLAB_H
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#define _LINUX_SLAB_H
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#include <linux/gfp.h>
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#include <linux/types.h>
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/*
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* Flags to pass to kmem_cache_create().
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* The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
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*/
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#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
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#define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
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#define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
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#define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
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#define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
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#define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
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#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
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/*
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* SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
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*
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* This delays freeing the SLAB page by a grace period, it does _NOT_
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* delay object freeing. This means that if you do kmem_cache_free()
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* that memory location is free to be reused at any time. Thus it may
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* be possible to see another object there in the same RCU grace period.
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*
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* This feature only ensures the memory location backing the object
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* stays valid, the trick to using this is relying on an independent
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* object validation pass. Something like:
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*
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* rcu_read_lock()
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* again:
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* obj = lockless_lookup(key);
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* if (obj) {
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* if (!try_get_ref(obj)) // might fail for free objects
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* goto again;
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*
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* if (obj->key != key) { // not the object we expected
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* put_ref(obj);
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* goto again;
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* }
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* }
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* rcu_read_unlock();
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*
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* See also the comment on struct slab_rcu in mm/slab.c.
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*/
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#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
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#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
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#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
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/* Flag to prevent checks on free */
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#ifdef CONFIG_DEBUG_OBJECTS
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# define SLAB_DEBUG_OBJECTS 0x00400000UL
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#else
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# define SLAB_DEBUG_OBJECTS 0x00000000UL
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#endif
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#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
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/* Don't track use of uninitialized memory */
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#ifdef CONFIG_KMEMCHECK
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# define SLAB_NOTRACK 0x01000000UL
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#else
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# define SLAB_NOTRACK 0x00000000UL
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#endif
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/* The following flags affect the page allocator grouping pages by mobility */
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#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
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#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
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/*
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* ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
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*
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* Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
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*
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* ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
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* Both make kfree a no-op.
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*/
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#define ZERO_SIZE_PTR ((void *)16)
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#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
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(unsigned long)ZERO_SIZE_PTR)
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/*
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* struct kmem_cache related prototypes
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*/
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void __init kmem_cache_init(void);
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int slab_is_available(void);
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struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
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unsigned long,
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void (*)(void *));
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void kmem_cache_destroy(struct kmem_cache *);
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int kmem_cache_shrink(struct kmem_cache *);
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void kmem_cache_free(struct kmem_cache *, void *);
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unsigned int kmem_cache_size(struct kmem_cache *);
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const char *kmem_cache_name(struct kmem_cache *);
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int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
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/*
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* Please use this macro to create slab caches. Simply specify the
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* name of the structure and maybe some flags that are listed above.
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*
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* The alignment of the struct determines object alignment. If you
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* f.e. add ____cacheline_aligned_in_smp to the struct declaration
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* then the objects will be properly aligned in SMP configurations.
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*/
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#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
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sizeof(struct __struct), __alignof__(struct __struct),\
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(__flags), NULL)
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/*
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* The largest kmalloc size supported by the slab allocators is
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* 32 megabyte (2^25) or the maximum allocatable page order if that is
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* less than 32 MB.
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*
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* WARNING: Its not easy to increase this value since the allocators have
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* to do various tricks to work around compiler limitations in order to
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* ensure proper constant folding.
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*/
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#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
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(MAX_ORDER + PAGE_SHIFT - 1) : 25)
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#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_HIGH)
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#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
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/*
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* Common kmalloc functions provided by all allocators
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*/
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void * __must_check __krealloc(const void *, size_t, gfp_t);
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void * __must_check krealloc(const void *, size_t, gfp_t);
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void kfree(const void *);
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void kzfree(const void *);
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size_t ksize(const void *);
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/*
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* Allocator specific definitions. These are mainly used to establish optimized
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* ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
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* selecting the appropriate general cache at compile time.
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*
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* Allocators must define at least:
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*
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* kmem_cache_alloc()
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* __kmalloc()
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* kmalloc()
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*
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* Those wishing to support NUMA must also define:
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*
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* kmem_cache_alloc_node()
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* kmalloc_node()
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*
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* See each allocator definition file for additional comments and
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* implementation notes.
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*/
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#ifdef CONFIG_SLUB
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#include <linux/slub_def.h>
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#elif defined(CONFIG_SLOB)
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#include <linux/slob_def.h>
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#else
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#include <linux/slab_def.h>
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#endif
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/**
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* kcalloc - allocate memory for an array. The memory is set to zero.
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* @n: number of elements.
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* @size: element size.
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* @flags: the type of memory to allocate.
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*
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* The @flags argument may be one of:
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*
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* %GFP_USER - Allocate memory on behalf of user. May sleep.
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*
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* %GFP_KERNEL - Allocate normal kernel ram. May sleep.
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*
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* %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
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* For example, use this inside interrupt handlers.
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*
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* %GFP_HIGHUSER - Allocate pages from high memory.
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*
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* %GFP_NOIO - Do not do any I/O at all while trying to get memory.
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*
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* %GFP_NOFS - Do not make any fs calls while trying to get memory.
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*
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* %GFP_NOWAIT - Allocation will not sleep.
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*
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* %GFP_THISNODE - Allocate node-local memory only.
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*
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* %GFP_DMA - Allocation suitable for DMA.
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* Should only be used for kmalloc() caches. Otherwise, use a
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* slab created with SLAB_DMA.
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*
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* Also it is possible to set different flags by OR'ing
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* in one or more of the following additional @flags:
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*
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* %__GFP_COLD - Request cache-cold pages instead of
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* trying to return cache-warm pages.
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*
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* %__GFP_HIGH - This allocation has high priority and may use emergency pools.
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*
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* %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
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* (think twice before using).
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*
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* %__GFP_NORETRY - If memory is not immediately available,
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* then give up at once.
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*
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* %__GFP_NOWARN - If allocation fails, don't issue any warnings.
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*
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* %__GFP_REPEAT - If allocation fails initially, try once more before failing.
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*
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* There are other flags available as well, but these are not intended
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* for general use, and so are not documented here. For a full list of
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* potential flags, always refer to linux/gfp.h.
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*/
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static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
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{
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if (size != 0 && n > ULONG_MAX / size)
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return NULL;
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return __kmalloc(n * size, flags | __GFP_ZERO);
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}
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#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
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/**
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* kmalloc_node - allocate memory from a specific node
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* @size: how many bytes of memory are required.
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* @flags: the type of memory to allocate (see kcalloc).
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* @node: node to allocate from.
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*
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* kmalloc() for non-local nodes, used to allocate from a specific node
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* if available. Equivalent to kmalloc() in the non-NUMA single-node
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* case.
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*/
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static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
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{
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return kmalloc(size, flags);
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}
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static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
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{
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return __kmalloc(size, flags);
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}
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void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
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static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
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gfp_t flags, int node)
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{
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return kmem_cache_alloc(cachep, flags);
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}
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#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
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/*
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* kmalloc_track_caller is a special version of kmalloc that records the
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* calling function of the routine calling it for slab leak tracking instead
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* of just the calling function (confusing, eh?).
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* It's useful when the call to kmalloc comes from a widely-used standard
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* allocator where we care about the real place the memory allocation
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* request comes from.
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*/
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#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
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extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
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#define kmalloc_track_caller(size, flags) \
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__kmalloc_track_caller(size, flags, _RET_IP_)
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#else
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#define kmalloc_track_caller(size, flags) \
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__kmalloc(size, flags)
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#endif /* DEBUG_SLAB */
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#ifdef CONFIG_NUMA
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/*
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* kmalloc_node_track_caller is a special version of kmalloc_node that
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* records the calling function of the routine calling it for slab leak
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* tracking instead of just the calling function (confusing, eh?).
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* It's useful when the call to kmalloc_node comes from a widely-used
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* standard allocator where we care about the real place the memory
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* allocation request comes from.
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*/
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#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
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extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
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#define kmalloc_node_track_caller(size, flags, node) \
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__kmalloc_node_track_caller(size, flags, node, \
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_RET_IP_)
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#else
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#define kmalloc_node_track_caller(size, flags, node) \
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__kmalloc_node(size, flags, node)
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#endif
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#else /* CONFIG_NUMA */
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#define kmalloc_node_track_caller(size, flags, node) \
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kmalloc_track_caller(size, flags)
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#endif /* CONFIG_NUMA */
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/*
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* Shortcuts
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*/
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static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
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{
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return kmem_cache_alloc(k, flags | __GFP_ZERO);
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}
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/**
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* kzalloc - allocate memory. The memory is set to zero.
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* @size: how many bytes of memory are required.
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* @flags: the type of memory to allocate (see kmalloc).
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*/
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static inline void *kzalloc(size_t size, gfp_t flags)
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{
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return kmalloc(size, flags | __GFP_ZERO);
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}
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/**
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* kzalloc_node - allocate zeroed memory from a particular memory node.
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* @size: how many bytes of memory are required.
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* @flags: the type of memory to allocate (see kmalloc).
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* @node: memory node from which to allocate
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*/
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static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
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{
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return kmalloc_node(size, flags | __GFP_ZERO, node);
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}
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void __init kmem_cache_init_late(void);
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#endif /* _LINUX_SLAB_H */
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