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Date:   Wed, 6 Dec 2023 18:35:42 +0900
From:   Hyeonggon Yoo <42.hyeyoo@gmail.com>
To:     Vlastimil Babka <vbabka@suse.cz>
Cc:     David Rientjes <rientjes@google.com>,
        Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Alexander Potapenko <glider@google.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Marco Elver <elver@google.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Shakeel Butt <shakeelb@google.com>,
        Muchun Song <muchun.song@linux.dev>,
        Kees Cook <keescook@chromium.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
        cgroups@vger.kernel.org, linux-hardening@vger.kernel.org
Subject: Re: [PATCH v2 10/21] mm/slab: move struct kmem_cache_cpu declaration
 to slub.c
Message-ID: <ZXBAbu7pR4o7JIa5@localhost.localdomain>
References: <20231120-slab-remove-slab-v2-0-9c9c70177183@suse.cz>
 <20231120-slab-remove-slab-v2-10-9c9c70177183@suse.cz>
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In-Reply-To: <20231120-slab-remove-slab-v2-10-9c9c70177183@suse.cz>
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On Mon, Nov 20, 2023 at 07:34:21PM +0100, Vlastimil Babka wrote:
> Nothing outside SLUB itself accesses the struct kmem_cache_cpu fields so
> it does not need to be declared in slub_def.h. This allows also to move
> enum stat_item.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  include/linux/slub_def.h | 54 ------------------------------------------------
>  mm/slub.c                | 54 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 54 insertions(+), 54 deletions(-)
> 
> diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
> index deb90cf4bffb..a0229ea42977 100644
> --- a/include/linux/slub_def.h
> +++ b/include/linux/slub_def.h
> @@ -12,60 +12,6 @@
>  #include <linux/reciprocal_div.h>
>  #include <linux/local_lock.h>
>  
> -enum stat_item {
> -	ALLOC_FASTPATH,		/* Allocation from cpu slab */
> -	ALLOC_SLOWPATH,		/* Allocation by getting a new cpu slab */
> -	FREE_FASTPATH,		/* Free to cpu slab */
> -	FREE_SLOWPATH,		/* Freeing not to cpu slab */
> -	FREE_FROZEN,		/* Freeing to frozen slab */
> -	FREE_ADD_PARTIAL,	/* Freeing moves slab to partial list */
> -	FREE_REMOVE_PARTIAL,	/* Freeing removes last object */
> -	ALLOC_FROM_PARTIAL,	/* Cpu slab acquired from node partial list */
> -	ALLOC_SLAB,		/* Cpu slab acquired from page allocator */
> -	ALLOC_REFILL,		/* Refill cpu slab from slab freelist */
> -	ALLOC_NODE_MISMATCH,	/* Switching cpu slab */
> -	FREE_SLAB,		/* Slab freed to the page allocator */
> -	CPUSLAB_FLUSH,		/* Abandoning of the cpu slab */
> -	DEACTIVATE_FULL,	/* Cpu slab was full when deactivated */
> -	DEACTIVATE_EMPTY,	/* Cpu slab was empty when deactivated */
> -	DEACTIVATE_TO_HEAD,	/* Cpu slab was moved to the head of partials */
> -	DEACTIVATE_TO_TAIL,	/* Cpu slab was moved to the tail of partials */
> -	DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
> -	DEACTIVATE_BYPASS,	/* Implicit deactivation */
> -	ORDER_FALLBACK,		/* Number of times fallback was necessary */
> -	CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
> -	CMPXCHG_DOUBLE_FAIL,	/* Number of times that cmpxchg double did not match */
> -	CPU_PARTIAL_ALLOC,	/* Used cpu partial on alloc */
> -	CPU_PARTIAL_FREE,	/* Refill cpu partial on free */
> -	CPU_PARTIAL_NODE,	/* Refill cpu partial from node partial */
> -	CPU_PARTIAL_DRAIN,	/* Drain cpu partial to node partial */
> -	NR_SLUB_STAT_ITEMS
> -};
> -
> -#ifndef CONFIG_SLUB_TINY
> -/*
> - * When changing the layout, make sure freelist and tid are still compatible
> - * with this_cpu_cmpxchg_double() alignment requirements.
> - */
> -struct kmem_cache_cpu {
> -	union {
> -		struct {
> -			void **freelist;	/* Pointer to next available object */
> -			unsigned long tid;	/* Globally unique transaction id */
> -		};
> -		freelist_aba_t freelist_tid;
> -	};
> -	struct slab *slab;	/* The slab from which we are allocating */
> -#ifdef CONFIG_SLUB_CPU_PARTIAL
> -	struct slab *partial;	/* Partially allocated frozen slabs */
> -#endif
> -	local_lock_t lock;	/* Protects the fields above */
> -#ifdef CONFIG_SLUB_STATS
> -	unsigned stat[NR_SLUB_STAT_ITEMS];
> -#endif
> -};
> -#endif /* CONFIG_SLUB_TINY */
> -
>  #ifdef CONFIG_SLUB_CPU_PARTIAL
>  #define slub_percpu_partial(c)		((c)->partial)
>  
> diff --git a/mm/slub.c b/mm/slub.c
> index 3e01731783df..979932d046fd 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -330,6 +330,60 @@ static void debugfs_slab_add(struct kmem_cache *);
>  static inline void debugfs_slab_add(struct kmem_cache *s) { }
>  #endif
>  
> +enum stat_item {
> +	ALLOC_FASTPATH,		/* Allocation from cpu slab */
> +	ALLOC_SLOWPATH,		/* Allocation by getting a new cpu slab */
> +	FREE_FASTPATH,		/* Free to cpu slab */
> +	FREE_SLOWPATH,		/* Freeing not to cpu slab */
> +	FREE_FROZEN,		/* Freeing to frozen slab */
> +	FREE_ADD_PARTIAL,	/* Freeing moves slab to partial list */
> +	FREE_REMOVE_PARTIAL,	/* Freeing removes last object */
> +	ALLOC_FROM_PARTIAL,	/* Cpu slab acquired from node partial list */
> +	ALLOC_SLAB,		/* Cpu slab acquired from page allocator */
> +	ALLOC_REFILL,		/* Refill cpu slab from slab freelist */
> +	ALLOC_NODE_MISMATCH,	/* Switching cpu slab */
> +	FREE_SLAB,		/* Slab freed to the page allocator */
> +	CPUSLAB_FLUSH,		/* Abandoning of the cpu slab */
> +	DEACTIVATE_FULL,	/* Cpu slab was full when deactivated */
> +	DEACTIVATE_EMPTY,	/* Cpu slab was empty when deactivated */
> +	DEACTIVATE_TO_HEAD,	/* Cpu slab was moved to the head of partials */
> +	DEACTIVATE_TO_TAIL,	/* Cpu slab was moved to the tail of partials */
> +	DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
> +	DEACTIVATE_BYPASS,	/* Implicit deactivation */
> +	ORDER_FALLBACK,		/* Number of times fallback was necessary */
> +	CMPXCHG_DOUBLE_CPU_FAIL,/* Failures of this_cpu_cmpxchg_double */
> +	CMPXCHG_DOUBLE_FAIL,	/* Failures of slab freelist update */
> +	CPU_PARTIAL_ALLOC,	/* Used cpu partial on alloc */
> +	CPU_PARTIAL_FREE,	/* Refill cpu partial on free */
> +	CPU_PARTIAL_NODE,	/* Refill cpu partial from node partial */
> +	CPU_PARTIAL_DRAIN,	/* Drain cpu partial to node partial */
> +	NR_SLUB_STAT_ITEMS
> +};
> +
> +#ifndef CONFIG_SLUB_TINY
> +/*
> + * When changing the layout, make sure freelist and tid are still compatible
> + * with this_cpu_cmpxchg_double() alignment requirements.
> + */
> +struct kmem_cache_cpu {
> +	union {
> +		struct {
> +			void **freelist;	/* Pointer to next available object */
> +			unsigned long tid;	/* Globally unique transaction id */
> +		};
> +		freelist_aba_t freelist_tid;
> +	};
> +	struct slab *slab;	/* The slab from which we are allocating */
> +#ifdef CONFIG_SLUB_CPU_PARTIAL
> +	struct slab *partial;	/* Partially allocated frozen slabs */
> +#endif
> +	local_lock_t lock;	/* Protects the fields above */
> +#ifdef CONFIG_SLUB_STATS
> +	unsigned int stat[NR_SLUB_STAT_ITEMS];
> +#endif
> +};
> +#endif /* CONFIG_SLUB_TINY */
> +
>  static inline void stat(const struct kmem_cache *s, enum stat_item si)
>  {
>  #ifdef CONFIG_SLUB_STATS

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

> 
> -- 
> 2.42.1
> 
>