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Tue, 8 Aug 2023 09:59:10 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id pPQqDe4R0mT/JwAAMHmgww (envelope-from ); Tue, 08 Aug 2023 09:59:10 +0000 Message-ID: Date: Tue, 8 Aug 2023 11:59:09 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: [RFC 2/2] mm/slub: prefer NUMA locality over slight memory saving on NUMA machines Content-Language: en-US To: Hyeonggon Yoo <42.hyeyoo@gmail.com> Cc: Christoph Lameter , Pekka Enberg , Joonsoo Kim , David Rientjes , Andrew Morton , Roman Gushchin , Feng Tang , "Sang, Oliver" , Jay Patel , Binder Makin , aneesh.kumar@linux.ibm.com, tsahu@linux.ibm.com, piyushs@linux.ibm.com, fengwei.yin@intel.com, ying.huang@intel.com, lkp , "oe-lkp@lists.linux.dev" , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20230723190906.4082646-1-42.hyeyoo@gmail.com> <20230723190906.4082646-3-42.hyeyoo@gmail.com> <1f88aff2-8027-1020-71b2-6a6528f82207@suse.cz> From: Vlastimil Babka In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: E08ABA0006 X-Stat-Signature: kbgzgyw7b3fty4un79w7xjdo5yd657gc X-HE-Tag: 1691488751-725221 X-HE-Meta: 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 7W0QwLiu F7GJVLvlNTozqkxx3H3xhn8PPj5nohtewIlNpjH89DCX1CN3GMzV3fHEXFIFNMHtFUPq3eF1ODtmQNJEhKBK9pE34ZM7jeiEPFCyH7Dyj2OhHA+WHJqG4C2A6i9ku1tEHz3pF6aJpvrPsodeGKI6QbGdE66TH2Qa2vFq7j4jPqPzZcmDhxlaDhBysNN/xYh14tmMA3keL3l4RW8noluyZX3UB29ZHCW+sIj3fVAyJXP/IpT5grx3G3xUrTrDOvn2QBX6/oWgmdtlW4Cj64DZRgf/cpFgWTWtEmppo09qMv2glem6flmRuFiVa2a7VvScKXlh/WxueQzBg6tPcpRWpL9DawjEHe8cDLZShgSz6YfQke13ewOWE7xxXmA== 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 8/7/23 10:39, Hyeonggon Yoo wrote: > On Thu, Aug 3, 2023 at 11:54 PM Vlastimil Babka wrote: >> > > Thank you for looking at it! > > Yeah, it was a PoC for what I thought "oh, it might be useful" > and definitely I will try to measure it. > >> We could also postpone this until we have tried the percpu arrays >> improvements discussed at LSF/MM. > > Possibly, but can you please share your plans/opinions on it? Here's the very first attempt :) https://lore.kernel.org/linux-mm/20230808095342.12637-7-vbabka@suse.cz/ > I think one possible way is simply to allow the cpu freelist to be > mixed by objects from different slabs I didn't try that way, might be much trickier than it looks. > if we want to minimize changes, Or introduce a per cpu array similar > to what SLAB does now. Yes. > And one thing I'm having difficulty understanding is - what is the > mind behind/or impact of managing objects > on a slab basis, other than avoiding array queues in 2007? "The mind" is Christoph's so I'll leave that question to him :)