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 DCCFE527597 for ; Fri, 18 Sep 2026 20:47:05 +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=1789764427; cv=none; b=oIHGK7Af8o+MAIJqGGb7H0fmoISH3w35Ib2nDJqa/o0Hti48jqjJkyJR+/gXCwKvAre6w82eFd4qPgksPJrPf0YpOJnANBS8nIqNPZEw07cskxtc7/jrxguEnOfGInJfYqERoQmQhqe2487o+GaHN3ZIs3dnPKMpSDGom7DnuQ0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789764427; c=relaxed/simple; bh=QKfVWVtIJcPuI7wVZek4I1PWhgmJqZeOzdiYlEijovA=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=AF45K6ef/SxArXu9Cbbk5QMza9r/I/U6QP7o80byqWW6OJzM3nWFuHe6yoknyOQLNmQLubBGQ81BqmZNGsxEt+AGr/hI/QnaBXaNMk6SMSjoBvnz452PIpemA1D0BIMiq1bs8JyzxuFlhWnjcp8royZZ0XPzHs6wXzoXFsDbauI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gKr6V+4u; 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="gKr6V+4u" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2FEF61F000FF; Fri, 18 Sep 2026 20:46:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789764425; bh=fe2KGn65vGnNk3T7Nd1gAbsrg0Fr2KhMni3HFhxALbc=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=gKr6V+4uPkVj2ijRbu8ZBVV3Ud/yBihVL2ETBxTzvm6vr8T1e78AA6m6p9jrqAR49 ShztAYhRkBZ7bmJ7P5viMWIlIPCE29GzfHWnwBRHK18Z5vCYYiQmnV/dzhB9V7Yvna bU/apqh0UnbIqX0PM+xZTtpgIyLV+FFkwagZTxGoDt7ogqmdOGjLgL94oWmmPaZD7J nTWFlWP4a3YtaV1trCe6gVQwlf27ANPq7BbP5vet9W0algcFfwWmHBhlTcHz/QjQnc oVOvmBSAeY+m7Vndreh8QE9xTEmZbFdWSsK3hBHYkiml75OVOZY6XLjlpxBsoUqJZO SbNTt1CRinRzQ== Message-ID: <6e542162-fe6c-47da-b0c4-a36251242950@kernel.org> Date: Fri, 18 Sep 2026 22:46:55 +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 v5 09/17] mm/huge_memory: rename remap_page() to remap_anon_folio() To: kasong@tencent.com, linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Chris Li , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , Yeoreum Yun , "Kiryl Shutsemau (Meta)" , Shivam Kalra , Kairui Song References: <20260915-swap-thp-cleanup-v5-0-39878b37dfb0@tencent.com> <20260915-swap-thp-cleanup-v5-9-39878b37dfb0@tencent.com> 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: <20260915-swap-thp-cleanup-v5-9-39878b37dfb0@tencent.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/14/26 19:14, Kairui Song via B4 Relay wrote: > From: Kairui Song > > remap_page() now only has one caller, __folio_freeze_split_anon(), > and is only ever called for anon folios: unmap_folio() currently > leaves file folios unmapped after the split, so they need no > remapping. > > Rename it to remap_anon_folio() to make that explicit, and add a > VM_WARN_ON_FOLIO() documenting it. > > Reviewed-by: Zi Yan > Reviewed-by: Kiryl Shutsemau (Meta) > Signed-off-by: Kairui Song > --- > mm/huge_memory.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index 1749905ade6a..77bf68c9b9af 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -3552,7 +3552,7 @@ static void unmap_folio(struct folio *folio) > /* > * Anon pages need migration entries to preserve them, but file > * pages can simply be left unmapped, then faulted back on demand. > - * If that is ever changed (perhaps for mlock), update remap_page(). > + * If that is ever changed (perhaps for mlock), update remap_anon_folio(). See my comment below, delete that comment about "what if X" entirely. Also, we wouldn't want to update remap_anon_folio(). > */ > if (folio_test_anon(folio)) > try_to_migrate(folio, ttu_flags); > @@ -3637,10 +3637,17 @@ bool unmap_huge_pmd_locked(struct vm_area_struct *vma, unsigned long addr, > return __discard_anon_folio_pmd_locked(vma, addr, pmdp, folio); > } > > -static void remap_page(struct folio *folio, unsigned long nr, int flags) > +static void remap_anon_folio(struct folio *folio, unsigned long nr, int flags) > { > int i = 0; > > + /* > + * unmap_folio() installs migration entries only for anon folios, > + * so currently only anon folios need to be remapped. File folios > + * stay unmapped after the split and are faulted back on demand. > + */ > + VM_WARN_ON_FOLIO(!folio_test_anon(folio), folio); > + > for (;;) { > remove_migration_ptes(folio, folio, TTU_RMAP_LOCKED | flags); > i += folio_nr_pages(folio); > @@ -3724,7 +3731,7 @@ static void __split_folio_to_order(struct folio *folio, int old_order, > * > * Note that for mapped sub-pages of an anonymous THP, > * PG_anon_exclusive has been cleared in unmap_folio() and is stored in > - * the migration entry instead from where remap_page() will restore it. > + * the migration entry instead from where remap_anon_folio() will restore it. > * We can still have PG_anon_exclusive set on effectively unmapped and > * unreferenced sub-pages of an anonymous THP: we can simply drop > * PG_anon_exclusive (-> PG_mappedtodisk) for these here. > @@ -4084,7 +4091,7 @@ static int __folio_freeze_split_anon(struct folio *folio, > if (need_remap) { > if (!ret && !folio_is_device_private(folio)) > ttu_flags = TTU_USE_SHARED_ZEROPAGE; > - remap_page(folio, 1 << old_order, ttu_flags); > + remap_anon_folio(folio, 1 << old_order, ttu_flags); > } > > return ret; > @@ -4206,7 +4213,7 @@ static int __folio_freeze_split_file(struct folio *folio, > fail: > /* > * If we want to use try_to_migrate() on file in unmap_folio, > - * remember to add remap_page() and adapt it. > + * remember to add remap_anon_folio() and adapt it. > */ Add remap_anon_folio for file folios? Just delete this entire code comment. Whoever wants to implement that can look into the pieces that are actually needed. With the comments sorted Acked-by: David Hildenbrand (Arm) -- Cheers, David