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t=1787062537; bh=Qx7Q9Tkm+30Vy5GpQNpuwA2/ZGcx6zXr2iqGQrjyaow=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=J4txqm8PSDHPtAGQRTxTA5BirFk7+ogzhOIXx818dDoEykvFj2mrVFD5zdFYcfFJ0 /jprkZRDFxQc8+QCcmNb0ApwCPKRCXrDv8FdOKGTuzZSBcmf10N4ZNE2LUmmbewdbR j4nU0aKvIRwA6/P+7rKRyvxb+WqvxxEYHHG++dyYmXrcmPJ4wvxfPuZA75WpgPVgxs f0B9a3AoNrZyoj+6NB3OnEml7VuMxDNvR+DUcxVjWZC/C0Sw9hEPBcvxjPfQATlp3A n0QvsdIbuzJrd8r8lo//noi6umHRcuvqsDdZ55Q9yQZXT5rNReYRnMfBHGHAV80cYT U4t5de0eRoHxA== Message-ID: <99138bda-55ba-4c58-9b79-b76e9daecdde@kernel.org> Date: Tue, 18 Aug 2026 16:15:27 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 00/57] mm/collapse: rebuild collapse on migration primitives To: Kiryl Shutsemau , "Lorenzo Stoakes (ARM)" Cc: akpm@linux-foundation.org, nico.pache@linux.dev, baolin.wang@linux.alibaba.com, baohua@kernel.org, dev.jain@arm.com, hughd@google.com, lance.yang@linux.dev, liam@infradead.org, mhocko@suse.com, rppt@kernel.org, ryan.roberts@arm.com, shuah@kernel.org, surenb@google.com, usama.arif@linux.dev, vbabka@kernel.org, ziy@nvidia.com, usama.anjum@arm.com, agordeev@linux.ibm.com, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, jannh@google.com, willy@infradead.org, pfalcato@suse.de, rostedt@goodmis.org, mhiramat@kernel.org, linux-trace-kernel@vger.kernel.org, bpf@vger.kernel.org References: <20260816224609.308019-1-kirill@shutemov.name> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: A92EC10000F X-Rspamd-Server: rspam10 X-Rspam-User: X-Stat-Signature: 4kcmrwogwj56k4a6u17ho69emjrsxbm6 X-HE-Tag: 1787062538-778333 X-HE-Meta: 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 rrnyc/Y7 nzQ413mYX1oECU8KUg3UQgll9AwW1SWgUxmEjYaHlDXX7snx/+kQtdD2oCbH4uNuuK4njNY7MwXDTwCjGh45fokZF06htaxyc+/am+v/8XFyYBgR9+2NpMtYpo0ZbCjsCjhFGsQireKNbIPBTUYdCOKQ4/1EKbDhycFBVue6jKNkOgOTwuzfP+zTZ1zp7eZSy1aybVCBrv0J1N1KthkN3Gwv16pHuF/KOav9KI/vpdvMsfAxDlhmmGDoSAwpS4K469HYu9dPmeYYRy2VOe54Nm3WMRQTS5IrgffYnM17bc88wNN1FcFweY5v30A== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/17/26 15:38, Kiryl Shutsemau wrote: > On Mon, Aug 17, 2026 at 09:52:13AM +0100, Lorenzo Stoakes (ARM) wrote: >> We have a THP cabal meeting every couple of weeks where it would have been >> useful for you to raise this first. > > Fair -- though my invite is on my old @linux.intel.com address. Could > you forward it to kas@kernel.org? > >> In any case - this series is not something we'd consider at the moment, >> even broken into parts. >> >> David and I have put THP into feature freeze - until the codebase is >> subtantially improved we're not really interested in seeing significant >> development. >> >> The technical debt is substantial and has to be paid down first. >> >> See [0] for a rough list of TODOs in this regard. > > I read the TODO list and I'll pick from it -- though I notice the > technical debt section includes "Literally all of the code in > mm/huge_memory.c and mm/khugepaged.c", which I'd argue this series is a > fairly committed attempt at :) > > One clean up I wanted to do is consolidate code by functionality, not by > the THP/non-THP split. Move all page fault handler code into mm/fault.c, > unmap code into mm/zap.c, fork's copying into mm/fork.c -- mirroring > kernel/fork.c, so the mm half of a subsystem sits under the same name. > Large folios are an integral part of mm nowadays and I don't think we > benefit from keeping THP in a separate file. It is also an opportunity to > shift away from mm/memory.c being a kitchen sink. > > David and I talked about this at LSF/MM. Ah, I missed the context in my other reply. Lorenzo already had some patches at some point to split up mm/memory.c into better chunks that will also better help our subcomponent maintenance model. I think the challenge is how to handle huge_memory.c, because ideally, we'd not have these stupid callbacks into huge_memory.c once we make PMDs just a first-class citizen. This is, unfortunately, also something that needs more thought, because we don't want to end up moving stuff back and forth. -- Cheers, David