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[2003:d8:2f18:f900:e0ae:65d5:8bf8:8cfd]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-45f2acbeee0sm67118205e9.0.2025.09.15.03.44.35 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Sep 2025 03:44:37 -0700 (PDT) Message-ID: <34754ca4-fced-4a3c-8ff8-c00967d487de@redhat.com> Date: Mon, 15 Sep 2025 12:44:34 +0200 Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v11 00/15] khugepaged: mTHP support To: Lorenzo Stoakes Cc: Kiryl Shutsemau , Nico Pache , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, ziy@nvidia.com, baolin.wang@linux.alibaba.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com, dev.jain@arm.com, corbet@lwn.net, rostedt@goodmis.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, akpm@linux-foundation.org, baohua@kernel.org, willy@infradead.org, peterx@redhat.com, wangkefeng.wang@huawei.com, usamaarif642@gmail.com, sunnanyong@huawei.com, vishal.moola@gmail.com, thomas.hellstrom@linux.intel.com, yang@os.amperecomputing.com, aarcange@redhat.com, raquini@redhat.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, tiwai@suse.de, will@kernel.org, dave.hansen@linux.intel.com, jack@suse.cz, cl@gentwo.org, jglisse@google.com, surenb@google.com, zokeefe@google.com, hannes@cmpxchg.org, rientjes@google.com, mhocko@suse.com, rdunlap@infradead.org, hughd@google.com, richard.weiyang@gmail.com, lance.yang@linux.dev, vbabka@suse.cz, rppt@kernel.org, jannh@google.com, pfalcato@suse.de References: <20250912032810.197475-1-npache@redhat.com> <2c5328ee-fb6e-45cf-a151-868cc8e7ff97@lucifer.local> <4508810d-7645-4f57-a0c5-2ee9f44206fc@lucifer.local> From: David Hildenbrand Content-Language: en-US Autocrypt: addr=david@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit >>> Mapping that to actual THP sizes (#pages in a thp) on an arch will be easy. >> >> And at different mTHP levels too right? >> > > Another point here, since we have to keep: > > /sys/kernel/mm/transparent_hugepage/khugepaged/max_ptes_none > > Around, and users will try to set values there, presumably we will now add: > > /sys/kernel/mm/transparent_hugepage/khugepaged/eagerness > > How will we map <-> the two tunables? Well, the easy case if someone updates eagerness, then we simply et it to whatever magic value we compute and document. The other direction is more problematic, likely we'll simply warn and do something reasonable (map it to whatever eagerness scale is closest or simply indicate it as "-1" -- user intervened or sth like that) -- Cheers David / dhildenb