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Message-ID: <d5a7f24c-52e6-471c-893e-44448efccbd4@suse.cz>
Date: Tue, 2 Apr 2024 11:45:45 +0200
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Subject: Re: [PATCH 1/4] mm/slub: remove the check of
 !kmem_cache_has_cpu_partial()
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To: xiongwei.song@windriver.com, rientjes@google.com, cl@linux.com,
 penberg@kernel.org, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org,
 roman.gushchin@linux.dev, 42.hyeyoo@gmail.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, chengming.zhou@linux.dev
References: <20240331021926.2732572-1-xiongwei.song@windriver.com>
 <20240331021926.2732572-2-xiongwei.song@windriver.com>
From: Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20240331021926.2732572-2-xiongwei.song@windriver.com>
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On 3/31/24 4:19 AM, xiongwei.song@windriver.com wrote:
> From: Xiongwei Song <xiongwei.song@windriver.com>
> 
> The check of !kmem_cache_has_cpu_partial(s) with
> CONFIG_SLUB_CPU_PARTIAL enabled here is always false. We have known the
> result by calling kmem_cacke_debug(). Here we can remove it.

Could we be more obvious. We have already checked kmem_cache_debug() earlier
and if it was true, the we either continued or broke from the loop so we
can't reach this code in that case and don't need to check
kmem_cache_debug() as part of kmem_cache_has_cpu_partial() again.

> Signed-off-by: Xiongwei Song <xiongwei.song@windriver.com>
> ---
>  mm/slub.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/mm/slub.c b/mm/slub.c
> index 1bb2a93cf7b6..059922044a4f 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -2610,8 +2610,7 @@ static struct slab *get_partial_node(struct kmem_cache *s,
>  			partial_slabs++;
>  		}
>  #ifdef CONFIG_SLUB_CPU_PARTIAL
> -		if (!kmem_cache_has_cpu_partial(s)
> -			|| partial_slabs > s->cpu_partial_slabs / 2)
> +		if (partial_slabs > s->cpu_partial_slabs / 2)
>  			break;
>  #else
>  		break;