Re: [PATCH] mm/slab: rename CONFIG_SLAB to CONFIG_SLAB_DEPRECATED

From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Christoph Lameter <cl@linux.com>,
	Pekka Enberg <penberg@kernel.org>,
	 David Rientjes <rientjes@google.com>,
	Joonsoo Kim <iamjoonsoo.kim@lge.com>,
	 Roman Gushchin <roman.gushchin@linux.dev>,
	Shawn Guo <shawnguo@kernel.org>,
	 Sascha Hauer <s.hauer@pengutronix.de>,
	Vladimir Zapolskiy <vz@mleia.com>, Andrew Lunn <andrew@lunn.ch>,
	 Gregory Clement <gregory.clement@bootlin.com>,
	 Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>,
	Tony Lindgren <tony@atomide.com>,  Qin Jian <qinjian@cqplus1.com>,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	 Dinh Nguyen <dinguyen@kernel.org>,
	 "James E . J . Bottomley"
	<James.Bottomley@hansenpartnership.com>,
	Helge Deller <deller@gmx.de>,
	 Yoshinori Sato <ysato@users.sourceforge.jp>,
	Rich Felker <dalias@libc.org>,
	 John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
	"David S . Miller" <davem@davemloft.net>,
	 Richard Weinberger <richard@nod.at>,
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	 Johannes Berg <johannes@sipsolutions.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	 linux-snps-arc@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
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	 linux-tegra@vger.kernel.org, linux-m68k@lists.linux-m68k.org,
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	 sparclinux@vger.kernel.org, linux-um@lists.infradead.org,
	linux-mm@kvack.org
Subject: Re: [PATCH] mm/slab: rename CONFIG_SLAB to CONFIG_SLAB_DEPRECATED
Date: Tue, 23 May 2023 19:58:03 +0900	[thread overview]
Message-ID: <CAB=+i9RycsnDbJ1f1jTiJ6fXnGUmH95h23G37Ss6XNAA3VJ3_w@mail.gmail.com> (raw)
In-Reply-To: <20230523091139.21449-1-vbabka@suse.cz>

On Tue, May 23, 2023 at 6:12 PM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> As discussed at LSF/MM [1] [2] and with no objections raised there,
> deprecate the SLAB allocator. Rename the user-visible option so that
> users with CONFIG_SLAB=y get a new prompt with explanation during make
> oldconfig, while make olddefconfig will just switch to SLUB.
>
> In all defconfigs with CONFIG_SLAB=y remove the line so those also
> switch to SLUB. Regressions due to the switch should be reported to
> linux-mm and slab maintainers.
>
> [1] https://lore.kernel.org/all/4b9fc9c6-b48c-198f-5f80-811a44737e5f@suse.cz/
> [2] https://lwn.net/Articles/932201/
>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---

<snip>

> diff --git a/mm/Kconfig b/mm/Kconfig
> index 7672a22647b4..b537c4436d18 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -218,11 +218,18 @@ choice
>         help
>            This option allows to select a slab allocator.
>
> -config SLAB
> -       bool "SLAB"
> +config SLAB_DEPRECATED
> +       bool "SLAB (DEPRECATED)"
>         depends on !PREEMPT_RT
>         select HAVE_HARDENED_USERCOPY_ALLOCATOR
>         help
> +         Deprecated and scheduled for removal in a few cycles. Replaced by
> +         SLUB.
> +
> +         If you cannot migrate to SLUB, please contact linux-mm@kvack.org
> +         and the people listed in the SLAB ALLOCATOR section of MAINTAINERS
> +         file, explaining why.
> +
>           The regular slab allocator that is established and known to work
>           well in all environments. It organizes cache hot objects in
>           per cpu and per node queues.
> @@ -240,6 +247,11 @@ config SLUB
>
>  endchoice
>
> +config SLAB
> +       bool
> +       default y
> +       depends on SLAB_DEPRECATED
> +
>  config SLUB_TINY
>         bool "Configure SLUB for minimal memory footprint"
>         depends on SLUB && EXPERT
> --
> 2.40.1

Thank you for the work!
It looks good to me.
let's see some users raise their voice.

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