Re: [PATCH v2 11/21] mm/slab: move the rest of slub_def.h to mm/slab.h

[Hyeonggon Yoo]

On Mon, Nov 20, 2023 at 07:34:22PM +0100, Vlastimil Babka wrote:
> mm/slab.h is the only place to include include/linux/slub_def.h which
> has allowed switching between SLAB and SLUB. Now we can simply move the
> contents over and remove slub_def.h.
> 
> Use this opportunity to fix up some whitespace (alignment) issues.
> 
> Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
>  include/linux/slub_def.h | 150 -----------------------------------------------
>  mm/slab.h                | 138 ++++++++++++++++++++++++++++++++++++++++++-
>  2 files changed, 137 insertions(+), 151 deletions(-)
> 
> diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
> deleted file mode 100644
> index a0229ea42977..000000000000
> --- a/include/linux/slub_def.h
> +++ /dev/null
> @@ -1,150 +0,0 @@
> -/* SPDX-License-Identifier: GPL-2.0 */
> -#ifndef _LINUX_SLUB_DEF_H
> -#define _LINUX_SLUB_DEF_H
> -
> -/*
> - * SLUB : A Slab allocator without object queues.
> - *
> - * (C) 2007 SGI, Christoph Lameter
> - */
> -#include <linux/kfence.h>
> -#include <linux/kobject.h>
> -#include <linux/reciprocal_div.h>
> -#include <linux/local_lock.h>
> -
> -#ifdef CONFIG_SLUB_CPU_PARTIAL
> -#define slub_percpu_partial(c)		((c)->partial)
> -
> -#define slub_set_percpu_partial(c, p)		\
> -({						\
> -	slub_percpu_partial(c) = (p)->next;	\
> -})
> -
> -#define slub_percpu_partial_read_once(c)     READ_ONCE(slub_percpu_partial(c))
> -#else
> -#define slub_percpu_partial(c)			NULL
> -
> -#define slub_set_percpu_partial(c, p)
> -
> -#define slub_percpu_partial_read_once(c)	NULL
> -#endif // CONFIG_SLUB_CPU_PARTIAL
> -
> -/*
> - * Word size structure that can be atomically updated or read and that
> - * contains both the order and the number of objects that a slab of the
> - * given order would contain.
> - */
> -struct kmem_cache_order_objects {
> -	unsigned int x;
> -};
> -
> -/*
> - * Slab cache management.
> - */
> -struct kmem_cache {
> -#ifndef CONFIG_SLUB_TINY
> -	struct kmem_cache_cpu __percpu *cpu_slab;
> -#endif
> -	/* Used for retrieving partial slabs, etc. */
> -	slab_flags_t flags;
> -	unsigned long min_partial;
> -	unsigned int size;	/* The size of an object including metadata */
> -	unsigned int object_size;/* The size of an object without metadata */
> -	struct reciprocal_value reciprocal_size;
> -	unsigned int offset;	/* Free pointer offset */
> -#ifdef CONFIG_SLUB_CPU_PARTIAL
> -	/* Number of per cpu partial objects to keep around */
> -	unsigned int cpu_partial;
> -	/* Number of per cpu partial slabs to keep around */
> -	unsigned int cpu_partial_slabs;
> -#endif
> -	struct kmem_cache_order_objects oo;
> -
> -	/* Allocation and freeing of slabs */
> -	struct kmem_cache_order_objects min;
> -	gfp_t allocflags;	/* gfp flags to use on each alloc */
> -	int refcount;		/* Refcount for slab cache destroy */
> -	void (*ctor)(void *);
> -	unsigned int inuse;		/* Offset to metadata */
> -	unsigned int align;		/* Alignment */
> -	unsigned int red_left_pad;	/* Left redzone padding size */
> -	const char *name;	/* Name (only for display!) */
> -	struct list_head list;	/* List of slab caches */
> -#ifdef CONFIG_SYSFS
> -	struct kobject kobj;	/* For sysfs */
> -#endif
> -#ifdef CONFIG_SLAB_FREELIST_HARDENED
> -	unsigned long random;
> -#endif
> -
> -#ifdef CONFIG_NUMA
> -	/*
> -	 * Defragmentation by allocating from a remote node.
> -	 */
> -	unsigned int remote_node_defrag_ratio;
> -#endif
> -
> -#ifdef CONFIG_SLAB_FREELIST_RANDOM
> -	unsigned int *random_seq;
> -#endif
> -
> -#ifdef CONFIG_KASAN_GENERIC
> -	struct kasan_cache kasan_info;
> -#endif
> -
> -#ifdef CONFIG_HARDENED_USERCOPY
> -	unsigned int useroffset;	/* Usercopy region offset */
> -	unsigned int usersize;		/* Usercopy region size */
> -#endif
> -
> -	struct kmem_cache_node *node[MAX_NUMNODES];
> -};
> -
> -#if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
> -#define SLAB_SUPPORTS_SYSFS
> -void sysfs_slab_unlink(struct kmem_cache *);
> -void sysfs_slab_release(struct kmem_cache *);
> -#else
> -static inline void sysfs_slab_unlink(struct kmem_cache *s)
> -{
> -}
> -static inline void sysfs_slab_release(struct kmem_cache *s)
> -{
> -}
> -#endif
> -
> -void *fixup_red_left(struct kmem_cache *s, void *p);
> -
> -static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab,
> -				void *x) {
> -	void *object = x - (x - slab_address(slab)) % cache->size;
> -	void *last_object = slab_address(slab) +
> -		(slab->objects - 1) * cache->size;
> -	void *result = (unlikely(object > last_object)) ? last_object : object;
> -
> -	result = fixup_red_left(cache, result);
> -	return result;
> -}
> -
> -/* Determine object index from a given position */
> -static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
> -					  void *addr, void *obj)
> -{
> -	return reciprocal_divide(kasan_reset_tag(obj) - addr,
> -				 cache->reciprocal_size);
> -}
> -
> -static inline unsigned int obj_to_index(const struct kmem_cache *cache,
> -					const struct slab *slab, void *obj)
> -{
> -	if (is_kfence_address(obj))
> -		return 0;
> -	return __obj_to_index(cache, slab_address(slab), obj);
> -}
> -
> -static inline int objs_per_slab(const struct kmem_cache *cache,
> -				     const struct slab *slab)
> -{
> -	return slab->objects;
> -}
> -#endif /* _LINUX_SLUB_DEF_H */
> diff --git a/mm/slab.h b/mm/slab.h
> index 014c36ea51fa..3a8d13c099fa 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -209,7 +209,143 @@ static inline size_t slab_size(const struct slab *slab)
>  	return PAGE_SIZE << slab_order(slab);
>  }
>  
> -#include <linux/slub_def.h>
> +#include <linux/kfence.h>
> +#include <linux/kobject.h>
> +#include <linux/reciprocal_div.h>
> +#include <linux/local_lock.h>
> +
> +#ifdef CONFIG_SLUB_CPU_PARTIAL
> +#define slub_percpu_partial(c)			((c)->partial)
> +
> +#define slub_set_percpu_partial(c, p)		\
> +({						\
> +	slub_percpu_partial(c) = (p)->next;	\
> +})
> +
> +#define slub_percpu_partial_read_once(c)	READ_ONCE(slub_percpu_partial(c))
> +#else
> +#define slub_percpu_partial(c)			NULL
> +
> +#define slub_set_percpu_partial(c, p)
> +
> +#define slub_percpu_partial_read_once(c)	NULL
> +#endif // CONFIG_SLUB_CPU_PARTIAL
> +
> +/*
> + * Word size structure that can be atomically updated or read and that
> + * contains both the order and the number of objects that a slab of the
> + * given order would contain.
> + */
> +struct kmem_cache_order_objects {
> +	unsigned int x;
> +};
> +
> +/*
> + * Slab cache management.
> + */
> +struct kmem_cache {
> +#ifndef CONFIG_SLUB_TINY
> +	struct kmem_cache_cpu __percpu *cpu_slab;
> +#endif
> +	/* Used for retrieving partial slabs, etc. */
> +	slab_flags_t flags;
> +	unsigned long min_partial;
> +	unsigned int size;		/* Object size including metadata */
> +	unsigned int object_size;	/* Object size without metadata */
> +	struct reciprocal_value reciprocal_size;
> +	unsigned int offset;		/* Free pointer offset */
> +#ifdef CONFIG_SLUB_CPU_PARTIAL
> +	/* Number of per cpu partial objects to keep around */
> +	unsigned int cpu_partial;
> +	/* Number of per cpu partial slabs to keep around */
> +	unsigned int cpu_partial_slabs;
> +#endif
> +	struct kmem_cache_order_objects oo;
> +
> +	/* Allocation and freeing of slabs */
> +	struct kmem_cache_order_objects min;
> +	gfp_t allocflags;		/* gfp flags to use on each alloc */
> +	int refcount;			/* Refcount for slab cache destroy */
> +	void (*ctor)(void *object);	/* Object constructor */
> +	unsigned int inuse;		/* Offset to metadata */
> +	unsigned int align;		/* Alignment */
> +	unsigned int red_left_pad;	/* Left redzone padding size */
> +	const char *name;		/* Name (only for display!) */
> +	struct list_head list;		/* List of slab caches */
> +#ifdef CONFIG_SYSFS
> +	struct kobject kobj;		/* For sysfs */
> +#endif
> +#ifdef CONFIG_SLAB_FREELIST_HARDENED
> +	unsigned long random;
> +#endif
> +
> +#ifdef CONFIG_NUMA
> +	/*
> +	 * Defragmentation by allocating from a remote node.
> +	 */
> +	unsigned int remote_node_defrag_ratio;
> +#endif
> +
> +#ifdef CONFIG_SLAB_FREELIST_RANDOM
> +	unsigned int *random_seq;
> +#endif
> +
> +#ifdef CONFIG_KASAN_GENERIC
> +	struct kasan_cache kasan_info;
> +#endif
> +
> +#ifdef CONFIG_HARDENED_USERCOPY
> +	unsigned int useroffset;	/* Usercopy region offset */
> +	unsigned int usersize;		/* Usercopy region size */
> +#endif
> +
> +	struct kmem_cache_node *node[MAX_NUMNODES];
> +};
> +
> +#if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY)
> +#define SLAB_SUPPORTS_SYSFS
> +void sysfs_slab_unlink(struct kmem_cache *s);
> +void sysfs_slab_release(struct kmem_cache *s);
> +#else
> +static inline void sysfs_slab_unlink(struct kmem_cache *s) { }
> +static inline void sysfs_slab_release(struct kmem_cache *s) { }
> +#endif
> +
> +void *fixup_red_left(struct kmem_cache *s, void *p);
> +
> +static inline void *nearest_obj(struct kmem_cache *cache,
> +				const struct slab *slab, void *x)
> +{
> +	void *object = x - (x - slab_address(slab)) % cache->size;
> +	void *last_object = slab_address(slab) +
> +		(slab->objects - 1) * cache->size;
> +	void *result = (unlikely(object > last_object)) ? last_object : object;
> +
> +	result = fixup_red_left(cache, result);
> +	return result;
> +}
> +
> +/* Determine object index from a given position */
> +static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
> +					  void *addr, void *obj)
> +{
> +	return reciprocal_divide(kasan_reset_tag(obj) - addr,
> +				 cache->reciprocal_size);
> +}
> +
> +static inline unsigned int obj_to_index(const struct kmem_cache *cache,
> +					const struct slab *slab, void *obj)
> +{
> +	if (is_kfence_address(obj))
> +		return 0;
> +	return __obj_to_index(cache, slab_address(slab), obj);
> +}
> +
> +static inline int objs_per_slab(const struct kmem_cache *cache,
> +				const struct slab *slab)
> +{
> +	return slab->objects;
> +}
>  
>  #include <linux/memcontrol.h>
>  #include <linux/fault-inject.h>

Looks good to me,
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>

> 
> -- 
> 2.42.1
> 
>