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Sun, 27 Nov 2022 03:05:58 -0800 (PST) Date: Sun, 27 Nov 2022 20:05:52 +0900 From: Hyeonggon Yoo <42.hyeyoo@gmail.com> To: Vlastimil Babka Cc: Christoph Lameter , David Rientjes , Joonsoo Kim , Pekka Enberg , Roman Gushchin , Andrew Morton , Linus Torvalds , Matthew Wilcox , patches@lists.linux.dev, Dennis Zhou , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 10/12] mm, slub: remove percpu slabs with CONFIG_SLUB_TINY Message-ID: References: <20221121171202.22080-1-vbabka@suse.cz> <20221121171202.22080-11-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221121171202.22080-11-vbabka@suse.cz> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669547160; a=rsa-sha256; cv=none; b=Yya1i/+VjhVOaKkXIxRdINC2ZbpGgDk5A2eMBT1Y8ml7t2OicrtHx85kmBM6X75zR5YYvT wfHylPOZWbfDdYMm7+6X4D1YctGj23fTqtvz7o7GmW9Rs7sXUOK1fSaRUfXgOUEkROFZKM QysOzpOMMUTGSyv74HkV/vyi3ac0JSk= ARC-Authentication-Results: i=1; imf20.hostedemail.com; 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dmarc=pass (policy=none) header.from=gmail.com X-Stat-Signature: 7c8bbpibnjwthciz3yfe59esxpzs9nsp X-Rspamd-Queue-Id: 6D7941C000D X-Rspamd-Server: rspam06 X-HE-Tag: 1669547160-534073 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 Mon, Nov 21, 2022 at 06:12:00PM +0100, Vlastimil Babka wrote: > SLUB gets most of its scalability by percpu slabs. However for > CONFIG_SLUB_TINY the goal is minimal memory overhead, not scalability. > Thus, #ifdef out the whole kmem_cache_cpu percpu structure and > associated code. Additionally to the slab page savings, this reduces > percpu allocator usage, and code size. [+Cc Dennis] Wondering if we can reduce (or zero) early reservation of percpu area when #if !defined(CONFIG_SLUB) || defined(CONFIG_SLUB_TINY)? > This change builds on recent commit c7323a5ad078 ("mm/slub: restrict > sysfs validation to debug caches and make it safe"), as caches with > enabled debugging also avoid percpu slabs and all allocations and > freeing ends up working with the partial list. With a bit more > refactoring by the preceding patches, use the same code paths with > CONFIG_SLUB_TINY. > > Signed-off-by: Vlastimil Babka -- Thanks, Hyeonggon