Date:   Tue, 14 Mar 2023 07:18:11 +0000
From:   Hyeonggon Yoo <42.hyeyoo@gmail.com>
To:     Vlastimil Babka <vbabka@suse.cz>
Cc:     Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Pekka Enberg <penberg@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        rcu@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, patches@lists.linux.dev,
        netdev@vger.kernel.org, linux-doc@vger.kernel.org
Subject: Re: [PATCH 1/7] mm/slob: remove CONFIG_SLOB
Message-ID: <ZBAfsx30uLNj4TJB@localhost>
References: <20230310103210.22372-1-vbabka@suse.cz>
 <20230310103210.22372-2-vbabka@suse.cz>
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On Fri, Mar 10, 2023 at 11:32:03AM +0100, Vlastimil Babka wrote:
> Remove SLOB from Kconfig and Makefile. Everything under #ifdef
> CONFIG_SLOB, and mm/slob.c is now dead code.
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  init/Kconfig               |  2 +-
>  kernel/configs/tiny.config |  1 -
>  mm/Kconfig                 | 22 ----------------------
>  mm/Makefile                |  1 -
>  4 files changed, 1 insertion(+), 25 deletions(-)
> 
> diff --git a/init/Kconfig b/init/Kconfig
> index 1fb5f313d18f..72ac3f66bc27 100644
> --- a/init/Kconfig
> +++ b/init/Kconfig
> @@ -973,7 +973,7 @@ config MEMCG
>  
>  config MEMCG_KMEM
>  	bool
> -	depends on MEMCG && !SLOB
> +	depends on MEMCG
>  	default y
>  
>  config BLK_CGROUP
> diff --git a/kernel/configs/tiny.config b/kernel/configs/tiny.config
> index c2f9c912df1c..144b2bd86b14 100644
> --- a/kernel/configs/tiny.config
> +++ b/kernel/configs/tiny.config
> @@ -7,6 +7,5 @@ CONFIG_KERNEL_XZ=y
>  # CONFIG_KERNEL_LZO is not set
>  # CONFIG_KERNEL_LZ4 is not set
>  # CONFIG_SLAB is not set
> -# CONFIG_SLOB_DEPRECATED is not set
>  CONFIG_SLUB=y
>  CONFIG_SLUB_TINY=y
> diff --git a/mm/Kconfig b/mm/Kconfig
> index 4751031f3f05..669399ab693c 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -238,30 +238,8 @@ config SLUB
>  	   and has enhanced diagnostics. SLUB is the default choice for
>  	   a slab allocator.
>  
> -config SLOB_DEPRECATED
> -	depends on EXPERT
> -	bool "SLOB (Simple Allocator - DEPRECATED)"
> -	depends on !PREEMPT_RT
> -	help
> -	   Deprecated and scheduled for removal in a few cycles. SLUB
> -	   recommended as replacement. CONFIG_SLUB_TINY can be considered
> -	   on systems with 16MB or less RAM.
> -
> -	   If you need SLOB to stay, please contact linux-mm@kvack.org and
> -	   people listed in the SLAB ALLOCATOR section of MAINTAINERS file,
> -	   with your use case.
> -
> -	   SLOB replaces the stock allocator with a drastically simpler
> -	   allocator. SLOB is generally more space efficient but
> -	   does not perform as well on large systems.
> -
>  endchoice
>  
> -config SLOB
> -	bool
> -	default y
> -	depends on SLOB_DEPRECATED
> -
>  config SLUB_TINY
>  	bool "Configure SLUB for minimal memory footprint"
>  	depends on SLUB && EXPERT
> diff --git a/mm/Makefile b/mm/Makefile
> index 8e105e5b3e29..2d9c1e7f6085 100644
> --- a/mm/Makefile
> +++ b/mm/Makefile
> @@ -81,7 +81,6 @@ obj-$(CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP)	+= hugetlb_vmemmap.o
>  obj-$(CONFIG_NUMA) 	+= mempolicy.o
>  obj-$(CONFIG_SPARSEMEM)	+= sparse.o
>  obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
> -obj-$(CONFIG_SLOB) += slob.o
>  obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
>  obj-$(CONFIG_KSM) += ksm.o
>  obj-$(CONFIG_PAGE_POISONING) += page_poison.o

With what Mike pointed:
(removing 'mm/Makefile:KCOV_INSTRUMENT_slob.o := n')

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

> -- 
> 2.39.2
>