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b=FMpVxGdpPcmoQhoTWRA74l9VtIt4BFA1T6OQNhUP51hok3ESmW7EaicWTGR4A1CvMJu/1yV7E7a5lKIEhNmQjndA2pu2kjEYsdBJ3PvBZ7Qz3Des7H0oVUt8QewKCCJjfmWthzS5zvqHnha2Zi2exeCXjvhGasnQ3rsJ+54wEGU= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from PH7PR12MB5805.namprd12.prod.outlook.com (2603:10b6:510:1d1::13) by PH0PR12MB5646.namprd12.prod.outlook.com (2603:10b6:510:143::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8377.16; Fri, 24 Jan 2025 09:03:00 +0000 Received: from PH7PR12MB5805.namprd12.prod.outlook.com ([fe80::11c7:4914:62f4:f4a3]) by PH7PR12MB5805.namprd12.prod.outlook.com ([fe80::11c7:4914:62f4:f4a3%6]) with mapi id 15.20.8356.020; Fri, 24 Jan 2025 09:03:00 +0000 Message-ID: <0571919b-52e1-4981-8d34-bcc781c0561a@amd.com> Date: Fri, 24 Jan 2025 14:32:42 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [LSF/MM/BPF TOPIC] Overhauling hot page detection and promotion based on PTE A bit scanning To: Hyeonggon Yoo , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , "lsf-pc@lists.linux-foundation.org" , "bharata@amd.com" Cc: kernel_team@skhynix.com, 42.hyeyoo@gmail.com, "gourry@gourry.net" , "nehagholkar@meta.com" , "abhishekd@meta.com" , "ying.huang@linux.alibaba.com" , "nphamcs@gmail.com" , "hannes@cmpxchg.org" , "feng.tang@intel.com" , "kbusch@meta.com" , "Hasan.Maruf@amd.com" , "sj@kernel.org" , "david@redhat.com" , "willy@infradead.org" , "k.shutemov@gmail.com" , "mgorman@techsingularity.net" , "vbabka@suse.cz" , "hughd@google.com" , "rientjes@google.com" , "shy828301@gmail.com" , "liam.howlett@oracle.com" , "peterz@infradead.org" , "mingo@redhat.com" , "nadav.amit@gmail.com" , "shivankg@amd.com" , "ziy@nvidia.com" , "jhubbard@nvidia.com" , "AneeshKumar.KizhakeVeetil@arm.com" , "linux-kernel@vger.kernel.org" , "jon.grimm@amd.com" , "santosh.shukla@amd.com" , "Michael.Day@amd.com" , "riel@surriel.com" , "weixugc@google.com" , "leesuyeon0506@gmail.com" , honggyu.kim@sk.com, "leillc@google.com" , "kmanaouil.dev@gmail.com" , "rppt@kernel.org" , "dave.hansen@intel.com" , yuanchu@google.com References: <20250123105721.424117-1-raghavendra.kt@amd.com> <0a9914f8-bec7-4e58-ab12-a87fe3876187@sk.com> Content-Language: en-US From: Raghavendra K T In-Reply-To: <0a9914f8-bec7-4e58-ab12-a87fe3876187@sk.com> Content-Type: text/plain; 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[...] >> Here is the list of potential discussion points: >> 1. Other improvements and enhancements to PTE A bit scanning approach. >> Use of >> multiple kernel threads, throttling improvements, promotion policies, >> per-process >> opt-in via prctl, virtual vs physical address based scanning, tuning >> hot page >> detection algorithm etc. > > Yuanchu's MGLRU periodic aging series [1] seems quite relevant here, > you might want to look at it. adding Yuanchu to Cc. Thank you for pointing that. > > By the way, do you have any reason why you'd prefer opt-in prctl > over per-memcg control? > opt-in prctl came in the MM alignment discussion, and have added that. per-memcg also definitely makes sense. I am not aware which is the most used usecase. But adding provision for both with one having more priority over other may be the way to go. Overall point here is to save time in unnecessary scanning. will be adding prctl in the upcoming version to start with. > [1] https://lore.kernel.org/all/20221214225123.2770216-1- > yuanchu@google.com/ >