Re: [PATCH] mm: slab: comment __GFP_ZERO case for kmem_cache_alloc

[Hyeonggon Yoo]

On Fri, Oct 07, 2022 at 10:03:12PM -0400, Alexander Aring wrote:
> This patch will add a comment for the __GFP_ZERO flag case for
> kmem_cache_alloc(). As the current comment mentioned that the flags only
> matters if the cache has no available objects it's different for the
> __GFP_ZERO flag which will ensure that the returned object is always
> zeroed in any case.
> 
> I have the feeling I run into this question already two times if the
> user need to zero the object or not, but the user does not need to zero
> the object afterwards. However another use of __GFP_ZERO and only zero
> the object if the cache has no available objects would also make no
> sense.
> 
> Signed-off-by: Alexander Aring <aahringo@xxxxxxxxxx>
> ---
>  mm/slab.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/slab.c b/mm/slab.c
> index 10e96137b44f..7a84c2aae85a 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -3482,7 +3482,8 @@ void *__kmem_cache_alloc_lru(struct kmem_cache *cachep, struct list_lru *lru,
>   * @flags: See kmalloc().
>   *
>   * Allocate an object from this cache.  The flags are only relevant
> - * if the cache has no available objects.
> + * if the cache has no available objects. Except flag __GFP_ZERO which
> + * will zero the returned object.
>   *
>   * Return: pointer to the new object or %NULL in case of error
>   */
> -- 
> 2.31.1
> 

Acked-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>

Thanks!

-- 
Thanks,
Hyeonggon