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0af8489b02
SLUB gets most of its scalability by percpu slabs. However for
CONFIG_SLUB_TINY the goal is minimal memory overhead, not scalability.
Thus, #ifdef out the whole kmem_cache_cpu percpu structure and
associated code. Additionally to the slab page savings, this reduces
percpu allocator usage, and code size.
This change builds on recent commit c7323a5ad0 ("mm/slub: restrict
sysfs validation to debug caches and make it safe"), as caches with
enabled debugging also avoid percpu slabs and all allocations and
freeing ends up working with the partial list. With a bit more
refactoring by the preceding patches, use the same code paths with
CONFIG_SLUB_TINY.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Christoph Lameter <cl@linux.com>
198 lines
6.1 KiB
C
198 lines
6.1 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_SLUB_DEF_H
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#define _LINUX_SLUB_DEF_H
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/*
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* SLUB : A Slab allocator without object queues.
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*
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* (C) 2007 SGI, Christoph Lameter
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*/
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#include <linux/kfence.h>
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#include <linux/kobject.h>
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#include <linux/reciprocal_div.h>
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#include <linux/local_lock.h>
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enum stat_item {
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ALLOC_FASTPATH, /* Allocation from cpu slab */
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ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
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FREE_FASTPATH, /* Free to cpu slab */
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FREE_SLOWPATH, /* Freeing not to cpu slab */
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FREE_FROZEN, /* Freeing to frozen slab */
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FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
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FREE_REMOVE_PARTIAL, /* Freeing removes last object */
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ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
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ALLOC_SLAB, /* Cpu slab acquired from page allocator */
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ALLOC_REFILL, /* Refill cpu slab from slab freelist */
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ALLOC_NODE_MISMATCH, /* Switching cpu slab */
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FREE_SLAB, /* Slab freed to the page allocator */
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CPUSLAB_FLUSH, /* Abandoning of the cpu slab */
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DEACTIVATE_FULL, /* Cpu slab was full when deactivated */
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DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */
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DEACTIVATE_TO_HEAD, /* Cpu slab was moved to the head of partials */
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DEACTIVATE_TO_TAIL, /* Cpu slab was moved to the tail of partials */
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DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
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DEACTIVATE_BYPASS, /* Implicit deactivation */
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ORDER_FALLBACK, /* Number of times fallback was necessary */
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CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
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CMPXCHG_DOUBLE_FAIL, /* Number of times that cmpxchg double did not match */
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CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
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CPU_PARTIAL_FREE, /* Refill cpu partial on free */
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CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
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CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */
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NR_SLUB_STAT_ITEMS };
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#ifndef CONFIG_SLUB_TINY
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/*
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* When changing the layout, make sure freelist and tid are still compatible
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* with this_cpu_cmpxchg_double() alignment requirements.
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*/
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struct kmem_cache_cpu {
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void **freelist; /* Pointer to next available object */
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unsigned long tid; /* Globally unique transaction id */
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struct slab *slab; /* The slab from which we are allocating */
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#ifdef CONFIG_SLUB_CPU_PARTIAL
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struct slab *partial; /* Partially allocated frozen slabs */
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#endif
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local_lock_t lock; /* Protects the fields above */
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#ifdef CONFIG_SLUB_STATS
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unsigned stat[NR_SLUB_STAT_ITEMS];
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#endif
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};
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#endif /* CONFIG_SLUB_TINY */
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#ifdef CONFIG_SLUB_CPU_PARTIAL
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#define slub_percpu_partial(c) ((c)->partial)
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#define slub_set_percpu_partial(c, p) \
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({ \
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slub_percpu_partial(c) = (p)->next; \
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})
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#define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c))
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#else
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#define slub_percpu_partial(c) NULL
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#define slub_set_percpu_partial(c, p)
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#define slub_percpu_partial_read_once(c) NULL
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#endif // CONFIG_SLUB_CPU_PARTIAL
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/*
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* Word size structure that can be atomically updated or read and that
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* contains both the order and the number of objects that a slab of the
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* given order would contain.
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*/
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struct kmem_cache_order_objects {
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unsigned int x;
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};
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/*
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* Slab cache management.
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*/
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struct kmem_cache {
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#ifndef CONFIG_SLUB_TINY
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struct kmem_cache_cpu __percpu *cpu_slab;
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#endif
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/* Used for retrieving partial slabs, etc. */
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slab_flags_t flags;
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unsigned long min_partial;
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unsigned int size; /* The size of an object including metadata */
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unsigned int object_size;/* The size of an object without metadata */
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struct reciprocal_value reciprocal_size;
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unsigned int offset; /* Free pointer offset */
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#ifdef CONFIG_SLUB_CPU_PARTIAL
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/* Number of per cpu partial objects to keep around */
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unsigned int cpu_partial;
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/* Number of per cpu partial slabs to keep around */
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unsigned int cpu_partial_slabs;
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#endif
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struct kmem_cache_order_objects oo;
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/* Allocation and freeing of slabs */
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struct kmem_cache_order_objects min;
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gfp_t allocflags; /* gfp flags to use on each alloc */
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int refcount; /* Refcount for slab cache destroy */
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void (*ctor)(void *);
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unsigned int inuse; /* Offset to metadata */
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unsigned int align; /* Alignment */
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unsigned int red_left_pad; /* Left redzone padding size */
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const char *name; /* Name (only for display!) */
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struct list_head list; /* List of slab caches */
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#ifdef CONFIG_SYSFS
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struct kobject kobj; /* For sysfs */
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#endif
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#ifdef CONFIG_SLAB_FREELIST_HARDENED
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unsigned long random;
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#endif
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#ifdef CONFIG_NUMA
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/*
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* Defragmentation by allocating from a remote node.
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*/
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unsigned int remote_node_defrag_ratio;
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#endif
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#ifdef CONFIG_SLAB_FREELIST_RANDOM
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unsigned int *random_seq;
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#endif
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#ifdef CONFIG_KASAN
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struct kasan_cache kasan_info;
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#endif
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#ifdef CONFIG_HARDENED_USERCOPY
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unsigned int useroffset; /* Usercopy region offset */
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unsigned int usersize; /* Usercopy region size */
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#endif
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struct kmem_cache_node *node[MAX_NUMNODES];
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};
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#if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
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#define SLAB_SUPPORTS_SYSFS
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void sysfs_slab_unlink(struct kmem_cache *);
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void sysfs_slab_release(struct kmem_cache *);
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#else
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static inline void sysfs_slab_unlink(struct kmem_cache *s)
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{
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}
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static inline void sysfs_slab_release(struct kmem_cache *s)
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{
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}
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#endif
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void *fixup_red_left(struct kmem_cache *s, void *p);
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static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
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void *x) {
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void *object = x - (x - slab_address(slab)) % cache->size;
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void *last_object = slab_address(slab) +
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(slab->objects - 1) * cache->size;
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void *result = (unlikely(object > last_object)) ? last_object : object;
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result = fixup_red_left(cache, result);
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return result;
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}
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/* Determine object index from a given position */
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static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
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void *addr, void *obj)
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{
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return reciprocal_divide(kasan_reset_tag(obj) - addr,
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cache->reciprocal_size);
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}
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static inline unsigned int obj_to_index(const struct kmem_cache *cache,
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const struct slab *slab, void *obj)
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{
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if (is_kfence_address(obj))
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return 0;
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return __obj_to_index(cache, slab_address(slab), obj);
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}
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static inline int objs_per_slab(const struct kmem_cache *cache,
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const struct slab *slab)
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{
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return slab->objects;
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}
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#endif /* _LINUX_SLUB_DEF_H */
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