Re: [PATCH v6 03/17] mm/slab: Simplify create_kmalloc_cache() args and make it static

[Vlastimil Babka <vbabka@suse.cz>]

On 5/31/23 17:48, Catalin Marinas wrote:
> In the slab variant of kmem_cache_init(), call new_kmalloc_cache()
> instead of initialising the kmalloc_caches array directly. With this,
> create_kmalloc_cache() is now only called from new_kmalloc_cache() in
> the same file, so make it static. In addition, the useroffset argument
> is always 0 while usersize is the same as size. Remove them.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

Nice cleanup, thanks!

> ---
>  mm/slab.c        |  6 +-----
>  mm/slab.h        |  5 ++---
>  mm/slab_common.c | 14 ++++++--------
>  3 files changed, 9 insertions(+), 16 deletions(-)
> 
> diff --git a/mm/slab.c b/mm/slab.c
> index bb57f7fdbae1..b7817dcba63e 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -1240,11 +1240,7 @@ void __init kmem_cache_init(void)
>  	 * Initialize the caches that provide memory for the  kmem_cache_node
>  	 * structures first.  Without this, further allocations will bug.
>  	 */
> -	kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache(
> -				kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL],
> -				kmalloc_info[INDEX_NODE].size,
> -				ARCH_KMALLOC_FLAGS, 0,
> -				kmalloc_info[INDEX_NODE].size);
> +	new_kmalloc_cache(INDEX_NODE, KMALLOC_NORMAL, ARCH_KMALLOC_FLAGS);
>  	slab_state = PARTIAL_NODE;
>  	setup_kmalloc_cache_index_table();
>  
> diff --git a/mm/slab.h b/mm/slab.h
> index f01ac256a8f5..592590fcddae 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -255,9 +255,8 @@ gfp_t kmalloc_fix_flags(gfp_t flags);
>  /* Functions provided by the slab allocators */
>  int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
>  
> -struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
> -			slab_flags_t flags, unsigned int useroffset,
> -			unsigned int usersize);
> +void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type,
> +			      slab_flags_t flags);
>  extern void create_boot_cache(struct kmem_cache *, const char *name,
>  			unsigned int size, slab_flags_t flags,
>  			unsigned int useroffset, unsigned int usersize);
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 607249785c07..7f069159aee2 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -658,17 +658,16 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
>  	s->refcount = -1;	/* Exempt from merging for now */
>  }
>  
> -struct kmem_cache *__init create_kmalloc_cache(const char *name,
> -		unsigned int size, slab_flags_t flags,
> -		unsigned int useroffset, unsigned int usersize)
> +static struct kmem_cache *__init create_kmalloc_cache(const char *name,
> +						      unsigned int size,
> +						      slab_flags_t flags)
>  {
>  	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
>  
>  	if (!s)
>  		panic("Out of memory when creating slab %s\n", name);
>  
> -	create_boot_cache(s, name, size, flags | SLAB_KMALLOC, useroffset,
> -								usersize);
> +	create_boot_cache(s, name, size, flags | SLAB_KMALLOC, 0, size);
>  	list_add(&s->list, &slab_caches);
>  	s->refcount = 1;
>  	return s;
> @@ -863,7 +862,7 @@ void __init setup_kmalloc_cache_index_table(void)
>  	}
>  }
>  
> -static void __init
> +void __init
>  new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
>  {
>  	if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) {
> @@ -880,8 +879,7 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
>  
>  	kmalloc_caches[type][idx] = create_kmalloc_cache(
>  					kmalloc_info[idx].name[type],
> -					kmalloc_info[idx].size, flags, 0,
> -					kmalloc_info[idx].size);
> +					kmalloc_info[idx].size, flags);
>  
>  	/*
>  	 * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
>