151 lines
4.9 KiB
C
151 lines
4.9 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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* (C) Linux Foundation 2008-2013
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* Unified interface for all 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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#include <linux/workqueue.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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* This is useful if we need to approach a kernel structure obliquely,
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* from its address obtained without the usual locking. We can lock
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* the structure to stabilize it and check it's still at the given address,
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* only if we can be sure that the memory has not been meanwhile reused
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* for some other kind of object (which our subsystem's lock might corrupt).
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*
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* rcu_read_lock before reading the address, then rcu_read_unlock after
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* taking the spinlock within the structure expected at that address.
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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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#ifdef CONFIG_FAILSLAB
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# define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
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#else
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# define SLAB_FAILSLAB 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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void __init kmem_cache_init(void);
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int slab_is_available(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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static inline void *krealloc(void *p, size_t new_size, gfp_t flags)
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{
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return __builtin_realloc(p, new_size);
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}
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static inline void kfree(void *p)
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{
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__builtin_free(p);
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}
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static __always_inline void *kmalloc(size_t size, gfp_t flags)
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{
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return __builtin_malloc(size);
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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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void *ret = __builtin_malloc(size);
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memset(ret, 0, size);
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return ret;
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}
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static inline void *kcalloc(size_t n, size_t size, uint32_t flags)
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{
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return (void*)kzalloc(n * size, 0);
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}
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static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
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{
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// if (size != 0 && n > SIZE_MAX / size)
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// return NULL;
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return (void*)kmalloc(n * size, flags);
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}
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#endif /* _LINUX_SLAB_H */
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