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Date:   Wed, 6 Dec 2023 17:28:18 +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 06/21] cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks
Message-ID: <ZXAwomfWa6fdcPQ+@localhost.localdomain>
References: <20231120-slab-remove-slab-v2-0-9c9c70177183@suse.cz>
 <20231120-slab-remove-slab-v2-6-9c9c70177183@suse.cz>
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On Mon, Nov 20, 2023 at 07:34:17PM +0100, Vlastimil Babka wrote:
> The CPUHP_SLAB_PREPARE hooks are only used by SLAB which is removed.
> SLUB defines them as NULL, so we can remove those altogether.
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  include/linux/cpuhotplug.h | 1 -
>  include/linux/slab.h       | 8 --------
>  kernel/cpu.c               | 5 -----
>  3 files changed, 14 deletions(-)
> 
> diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
> index d305db70674b..07cb8f7030b6 100644
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -108,7 +108,6 @@ enum cpuhp_state {
>  	CPUHP_X2APIC_PREPARE,
>  	CPUHP_SMPCFD_PREPARE,
>  	CPUHP_RELAY_PREPARE,
> -	CPUHP_SLAB_PREPARE,
>  	CPUHP_MD_RAID5_PREPARE,
>  	CPUHP_RCUTREE_PREP,
>  	CPUHP_CPUIDLE_COUPLED_PREPARE,
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index d6d6ffeeb9a2..34e43cddc520 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -788,12 +788,4 @@ size_t kmalloc_size_roundup(size_t size);
>  
>  void __init kmem_cache_init_late(void);
>  
> -#if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
> -int slab_prepare_cpu(unsigned int cpu);
> -int slab_dead_cpu(unsigned int cpu);
> -#else
> -#define slab_prepare_cpu	NULL
> -#define slab_dead_cpu		NULL
> -#endif
> -
>  #endif	/* _LINUX_SLAB_H */
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 9e4c6780adde..530b026d95a1 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -2125,11 +2125,6 @@ static struct cpuhp_step cpuhp_hp_states[] = {
>  		.startup.single		= relay_prepare_cpu,
>  		.teardown.single	= NULL,
>  	},
> -	[CPUHP_SLAB_PREPARE] = {
> -		.name			= "slab:prepare",
> -		.startup.single		= slab_prepare_cpu,
> -		.teardown.single	= slab_dead_cpu,
> -	},
>  	[CPUHP_RCUTREE_PREP] = {
>  		.name			= "RCU/tree:prepare",
>  		.startup.single		= rcutree_prepare_cpu,

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

> 
> -- 
> 2.42.1
> 
>