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Thu, 24 Nov 2022 03:41:01 -0800 (PST) Date: Thu, 24 Nov 2022 20:40:55 +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, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 05/12] mm, slub: lower the default slub_max_order with CONFIG_SLUB_TINY Message-ID: References: <20221121171202.22080-1-vbabka@suse.cz> <20221121171202.22080-6-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221121171202.22080-6-vbabka@suse.cz> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669290063; a=rsa-sha256; cv=none; b=wVv7UYEE7pxtSUvnWFo2BHUFlUqfnCxof+SbtqY10dRRu7GVwVhVojwRXEGWxZVtBs14rg 54KnuQYarFbC8K3/PecksvpE0wj250fnuHVuvdR8kgzE9ryaIRxqf+1sL3FzHj/CN/aZcG maWb3WyfM3OIN6SRWh+3nyXaAhbX7GY= ARC-Authentication-Results: i=1; imf06.hostedemail.com; 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dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf06.hostedemail.com: domain of 42.hyeyoo@gmail.com designates 209.85.215.174 as permitted sender) smtp.mailfrom=42.hyeyoo@gmail.com X-Rspamd-Server: rspam09 X-HE-Tag: 1669290063-719642 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 06:11:55PM +0100, Vlastimil Babka wrote: > With CONFIG_SLUB_TINY we want to minimize memory overhead. By lowering > the default slub_max_order we can make slab allocations use smaller > pages. However depending on object sizes, order-0 might not be the best > due to increased fragmentation. When testing on a 8MB RAM k210 system by > Damien Le Moal [1], slub_max_order=1 had the best results, so use that > as the default for CONFIG_SLUB_TINY. > > [1] https://lore.kernel.org/all/6a1883c4-4c3f-545a-90e8-2cd805bcf4ae@opensource.wdc.com/ > > Signed-off-by: Vlastimil Babka > --- > mm/slub.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/slub.c b/mm/slub.c > index 917b79278bad..bf726dd00f7d 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -3888,7 +3888,8 @@ EXPORT_SYMBOL(kmem_cache_alloc_bulk); > * take the list_lock. > */ > static unsigned int slub_min_order; > -static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER; > +static unsigned int slub_max_order = > + IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER; > static unsigned int slub_min_objects; > > /* > -- > 2.38.1 > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com> -- Thanks, Hyeonggon