From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E1483431E40 for ; Wed, 1 Jul 2026 20:50:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782939040; cv=none; b=LYnDCUm7lPOkNVM/YpuBvnHEuCKO0+zMPAfwDASdTwKAEvhLia2lEJdUUgbGIsPepuXmySPoddgqkvJgSy5PssIlBJrAz/VMRMm76ZvNUVxMtf2EeGP4YAJoF9DDN1DkOPjSFeyO/LC97J5Y54wwtyCDGpFmOcZX3fMmougihik= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782939040; c=relaxed/simple; bh=Yb7Tqz31j5eWGZjZZwQbnHdWfln0AojaGpgjUqyIfqs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ZyBRvaU0z7NlG1iaq1zEzwDADBdMQUG1oYbozhtXosQh6GYL7Am3SyHg12cT1KLfqCapQvfT0pqQUDDgGaOwn5wyLscdhQc5Nv3OmWVaxxQnAK3LZNfxZfPSpavojEgzVCekJJ2I5b3rak5IdEf6PuZbyLEcgsKIPlzNdzzvOqg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SwrkgrAi; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SwrkgrAi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54EDB1F000E9; Wed, 1 Jul 2026 20:50:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782939039; bh=a94tkgNnnL5kMxxDMFtEEwz/ySLiqDiVpe8KXn83+aA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=SwrkgrAiEq8jy3oG8/48nH8/S/Hf4X4rDy3Y3GSSlAU2GD1wKzV2DzrHKQ8ebjMLR qNHgixbj5eNqur5I56ZTrzIO++eH5BoYRFgBFPCbJT4rnU6Lio9n8FEXYzkRMC/BVX ETPb7Nix/IsesYDEKt9G3UThsu3h3povJwdPhID2VKep0d5zd1BY0Pk3NHA2vAeQ8S jo5XZ8Pw5c6RTddzpzOuOerNEW8aQrnmTnU62FHsS0ruwCTc9hS6Mo0AJFXKJNZOsU h7eaii1nTIiFrCvtBfjYgF8A7Ei6NiRLwyAoT91HIYuxtI/SH7hUTo75UQTNPlRMiZ CQGPW+UzO/QmA== Message-ID: <03395825-2455-4b9d-b1bb-4232738afb30@kernel.org> Date: Wed, 1 Jul 2026 22:50:30 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 6/6] mm: rename ARCH_ENABLE_THP_MIGRATION to ARCH_SUPPORTS_PMD_SOFTLEAF To: Zi Yan Cc: Usama Arif , Andrew Morton , chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, linux-mm@kvack.org, ying.huang@linux.alibaba.com, Baoquan He , willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, npache@redhat.com, "Liam R. Howlett" , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, kernel-team@meta.com References: <20260630164143.1595669-1-usama.arif@linux.dev> <20260630164143.1595669-7-usama.arif@linux.dev> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/1/26 22:39, Zi Yan wrote: > On 1 Jul 2026, at 16:03, David Hildenbrand (Arm) wrote: > >> On 6/30/26 18:34, Usama Arif wrote: >>> CONFIG_ARCH_ENABLE_THP_MIGRATION started life gating just PMD-level >>> migration entries, but has grown to gate the entire PMD-level softleaf >>> machinery: migration entries, device-private entries, and soon swap >>> entries. >> >> device-private really relies on migration support. >> >> See do_huge_pmd_device_private() where we migrate back to CPU memory. >> >> The whole concept is pased on migration. So that's why it currently makes sense. >> >> So "has grown to" is not quite accurate. It's a different story with swap >> entries (that can exist even without migration support). >> >> >>> Rename CONFIG_ARCH_ENABLE_THP_MIGRATION to CONFIG_ARCH_SUPPORTS_PMD >>> _SOFTLEAF to make this clear. This is a pure rename: the set of >>> selecting architectures (x86, arm64, s390, riscv, loongarch, and >>> powerpc on PPC_BOOK3S_64) and the gating semantics are unchanged. >> >> Hm, that makes me wonder what it would take to make this all just be implicitly >> supported by CONFIG_TRANSPARENT_HUGEPAGE. >> >> Looks like someone would have the courage to touch stuff like arc, mips and >> sparc64 (+arm and x86, but that's less of a concern :) ). > > You mean me back in 2018[1]? ;) > > At least I got a no go for s390. hah! and 8 years later it seems to exist upstream :) commit 10dd5a0009898ba35eafeb6087e5c83b84742ff1 Author: Gerald Schaefer Date: Tue Jul 29 13:16:19 2025 +0200 s390/mm: Enable THP_SWAP and THP_MIGRATION After hugetlbfs PTE_MARKER support for s390 introduced region-third and segment table swap entries, it is now possible to also enable THP_SWAP and THP_MIGRATION for s390. So, with that out of the way, could you revive your patchset? -- Cheers, David