RE: [PATCH 1/3] mm, slab: deprecate SLAB_MEM_SPREAD flag

[Song, Xiongwei]

> The SLAB_MEM_SPREAD flag used to be implemented in SLAB, which was
> removed.  SLUB instead relies on the page allocator's NUMA policies.
> Change the flag's value to 0 to free up the value it had, and mark it
> for full removal once all users are gone.
> 
> Reported-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Closes: https://lore.kernel.org/all/20240131172027.10f64405@xxxxxxxxxxxxxxxxxx/
> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx>

Ran a rough test with build and bootup, feel free to add

Tested-by: Xiongwei Song <xiongwei.song@xxxxxxxxxxxxx>
Reviewed-by: Xiongwei Song <xiongwei.song@xxxxxxxxxxxxx>

> ---
>  include/linux/slab.h | 5 +++--
>  mm/slab.h            | 1 -
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index b5f5ee8308d0..6252f44115c2 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -96,8 +96,6 @@
>   */
>  /* Defer freeing slabs to RCU */
>  #define SLAB_TYPESAFE_BY_RCU   ((slab_flags_t __force)0x00080000U)
> -/* Spread some memory over cpuset */
> -#define SLAB_MEM_SPREAD                ((slab_flags_t __force)0x00100000U)
>  /* Trace allocations and frees */
>  #define SLAB_TRACE             ((slab_flags_t __force)0x00200000U)
> 
> @@ -164,6 +162,9 @@
>  #endif
>  #define SLAB_TEMPORARY         SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
> 
> +/* Obsolete unused flag, to be removed */
> +#define SLAB_MEM_SPREAD                0
> +
>  /*
>   * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
>   *
> diff --git a/mm/slab.h b/mm/slab.h
> index 54deeb0428c6..f4534eefb35d 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -469,7 +469,6 @@ static inline bool is_kmalloc_cache(struct kmem_cache *s)
>                               SLAB_STORE_USER | \
>                               SLAB_TRACE | \
>                               SLAB_CONSISTENCY_CHECKS | \
> -                             SLAB_MEM_SPREAD | \
>                               SLAB_NOLEAKTRACE | \
>                               SLAB_RECLAIM_ACCOUNT | \
>                               SLAB_TEMPORARY | \
> 
> --
> 2.43.1