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Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.5.0 Subject: Re: [PATCH 12/12] mm, slob: rename CONFIG_SLOB to CONFIG_SLOB_DEPRECATED Content-Language: en-US To: Christoph Lameter , David Rientjes , Joonsoo Kim , Pekka Enberg Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com>, Roman Gushchin , Andrew Morton , Linus Torvalds , Matthew Wilcox , patches@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Russell King , Aaro Koskinen , Janusz Krzysztofik , Tony Lindgren , Jonas Bonn , Stefan Kristiansson , Stafford Horne , Yoshinori Sato , Rich Felker , Arnd Bergmann , Josh Triplett , Conor Dooley , Damien Le Moal , Christophe Leroy , Geert Uytterhoeven , linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, openrisc@lists.librecores.org, linux-riscv@lists.infradead.org, linux-sh@vger.kernel.org References: <20221121171202.22080-1-vbabka@suse.cz> <20221121171202.22080-13-vbabka@suse.cz> From: Vlastimil Babka In-Reply-To: <20221121171202.22080-13-vbabka@suse.cz> Content-Type: text/plain; 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bh=HK8SHrswSKDS6/O+Mgs+PmBluOOCcSpzcSHcaJVrEzE=; b=oG+kmhqClbsgpBBNXykUAQ1v7vAMvoMM72b9FZiCiYWsS8A/Vq9BV3s5MpWPlBjAXz6wIZ iK85pknq3+xUUeT8RWRmcWe4ylfvgzjkIwTph+s/hsnNlCCkwuoDWKem9VXDtLWEWoqZBI O3w0kI3LssMuoTheVjOXrq/qee/XBr0= X-Stat-Signature: of8xj33jhhe1wbzzojej7wz37mhurtjk X-Rspamd-Queue-Id: 9F0D3C000B X-Rspam-User: Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=suse.cz header.s=susede2_rsa header.b=sGBGsUvn; dkim=pass header.d=suse.cz header.s=susede2_ed25519 header.b=RHu+rIna; spf=pass (imf22.hostedemail.com: domain of vbabka@suse.cz designates 195.135.220.28 as permitted sender) smtp.mailfrom=vbabka@suse.cz; dmarc=none X-Rspamd-Server: rspam02 X-HE-Tag: 1669059881-744004 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 11/21/22 18:12, Vlastimil Babka wrote: > As explained in [1], we would like to remove SLOB if possible. > > - There are no known users that need its somewhat lower memory footprint > so much that they cannot handle SLUB (after some modifications by the > previous patches) instead. > > - It is an extra maintenance burden, and a number of features are > incompatible with it. > > - It blocks the API improvement of allowing kfree() on objects allocated > via kmem_cache_alloc(). > > As the first step, rename the CONFIG_SLOB option in the slab allocator > configuration choice to CONFIG_SLOB_DEPRECATED. Add CONFIG_SLOB > depending on CONFIG_SLOB_DEPRECATED as an internal option to avoid code > churn. This will cause existing .config files and defconfigs with > CONFIG_SLOB=y to silently switch to the default (and recommended > replacement) SLUB, while still allowing SLOB to be configured by anyone > that notices and needs it. But those should contact the slab maintainers > and linux-mm@kvack.org as explained in the updated help. With no valid > objections, the plan is to update the existing defconfigs to SLUB and > remove SLOB in a few cycles. > > To make SLUB more suitable replacement for SLOB, a CONFIG_SLUB_TINY > option was introduced to limit SLUB's memory overhead. > There is a number of defconfigs specifying CONFIG_SLOB=y. As part of > this patch, update them to select CONFIG_SLUB and CONFIG_SLUB_TINY. Hm I forgot - some of those defconfigs might not actually be for so tiny devices to need CONFIG_SLUB_TINY (or SLOB previously). For those it would make more sense to simply remove CONFIG_SLOB=y and leave it to the default choice, which is SLUB (without _TINY). Feel free to point those out to me and I'll adjust. Thanks. > [1] https://lore.kernel.org/all/b35c3f82-f67b-2103-7d82-7a7ba7521439@suse.cz/ > > Cc: Russell King > Cc: Aaro Koskinen > Cc: Janusz Krzysztofik > Cc: Tony Lindgren > Cc: Jonas Bonn > Cc: Stefan Kristiansson > Cc: Stafford Horne > Cc: Yoshinori Sato > Cc: Rich Felker > Cc: Arnd Bergmann > Cc: Josh Triplett > Cc: Conor Dooley > Cc: Damien Le Moal > Cc: Christophe Leroy > Cc: Geert Uytterhoeven > Cc: > Cc: > Cc: > Cc: > Cc: > Signed-off-by: Vlastimil Babka