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imf24.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=bxMLcIyF; spf=pass (imf24.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772098090; a=rsa-sha256; cv=none; b=cKC1GpwvBNvWkCl/60zhaNQAg5JTmo14pvxLBvB9wC8eO0Bi297NYzW6li5msPPZc0yXc6 maVpTEdAGOt94KZYvdVRN2otPrmrSTmJUbxGQxC6TsiH3nCiCc/w6xJa0B4p0dTWuCYyRX 8ITgRaMx/rXelW2Rki6cdMg90sSnjM4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 13AE742B0F; Thu, 26 Feb 2026 09:28:09 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74B4CC19425; Thu, 26 Feb 2026 09:27:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772098088; bh=rgQOASaEYaTnnA/hyNxk7Xs4bJb1VJjlN0QqngKbpqc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=bxMLcIyFw+HsCDeyhLytU64ia68W3qqqTiRWYJZwH3Mw5P62fDVb+xqcp7JewiW/Z Uor+8JtA2/ngkAi57ddJwXAhNRwK4FnRiag2qcFeLFHohKGzNFOncPccbl3B4UwJzK 2I+Z/R8tCwdDRMeLr970Z5dyn0pBN2sjVG44pk7uATFzbMZ2CReu7KJsQ6Jjn17aNH 2c+tIrAOa7h+FuxfQy/lvM7FgaFebx94+9/DKQ4fuUNsN54v6YRz00a1PEOZKlSLwo GhsgBSGsCRZCFNM7CQbuXcy3fNKZ9R7pkSENQS+SprmUecuAx3GKiFh7oPrk338gT2 7YPPx/HVe0jqg== Message-ID: <7334b702-f6a0-4ccf-8ac6-8426a90d1846@kernel.org> Date: Thu, 26 Feb 2026 10:27:54 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-unstable v2 1/5] mm: consolidate anonymous folio PTE mapping into helpers To: Nico Pache , linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jackmanb@google.com, jack@suse.cz, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com References: <20260226012929.169479-1-npache@redhat.com> <20260226012929.169479-2-npache@redhat.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: <20260226012929.169479-2-npache@redhat.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: jnbzzfee6qe3gxphxmeoxydxei6om9at X-Rspamd-Server: rspam11 X-Rspam-User: X-Rspamd-Queue-Id: 1E12E180008 X-HE-Tag: 1772098089-254820 X-HE-Meta: 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 Vh9WtpK6 0HltbIYw9Nd2dYmOqE8JDf6YDlNwipvM3Ef64bzF7a3OqfkX40y9za1J/OZ1zOjX5Ed47bEaLH5kukAKye3Jd6LWFDNU5rQHWSHPq5OJTjO9sGcT1qHfMPtESuf/hOtSs60Ba4McrCEEOfoAu0nb1eBQYUi/Tdvjcnl+syokL9Mj3COTwjulz9L4LM1xwIJzi4pRE9IJ7dl9tmuD61xlwzFSQpPYEXSlhwhuwQZvIc0TrBiiB/LFpCIYbDViNjha2rTGM3AWnEsI9JEfh4hyEBUBDtcPFaN6DhMTAqwaj89nx1kCNJhz3nR843V2pcr5z30t3qj84xMFHiRsKuhdKyU6zXg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/26/26 02:29, Nico Pache wrote: > The anonymous page fault handler in do_anonymous_page() open-codes the > sequence to map a newly allocated anonymous folio at the PTE level: > - construct the PTE entry > - add rmap > - add to LRU > - set the PTEs > - update the MMU cache. > > Introduce a two helpers to consolidate this duplicated logic, mirroring the > existing map_anon_folio_pmd_nopf() pattern for PMD-level mappings: > > map_anon_folio_pte_nopf(): constructs the PTE entry, takes folio > references, adds anon rmap and LRU. This function also handles the > uffd_wp that can occur in the pf variant. > > map_anon_folio_pte_pf(): extends the nopf variant to handle MM_ANONPAGES > counter updates, and mTHP fault allocation statistics for the page fault > path. > > The zero-page read path in do_anonymous_page() is also untangled from the > shared setpte label, since it does not allocate a folio and should not > share the same mapping sequence as the write path. Make nr_pages = 1 > rather than relying on the variable. This makes it more clear that we > are operating on the zero page only. > > This refactoring will also help reduce code duplication between mm/memory.c > and mm/khugepaged.c, and provides a clean API for PTE-level anonymous folio > mapping that can be reused by future callers. > > Signed-off-by: Nico Pache > --- > include/linux/mm.h | 4 ++++ > mm/memory.c | 59 +++++++++++++++++++++++++++++++--------------- > 2 files changed, 44 insertions(+), 19 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 13336340612e..3ebf143c7502 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -4901,4 +4901,8 @@ static inline bool snapshot_page_is_faithful(const struct page_snapshot *ps) > > void snapshot_page(struct page_snapshot *ps, const struct page *page); > > +void map_anon_folio_pte_nopf(struct folio *folio, pte_t *pte, > + struct vm_area_struct *vma, unsigned long addr, > + bool uffd_wp); > + > #endif /* _LINUX_MM_H */ > diff --git a/mm/memory.c b/mm/memory.c > index 9385842c3503..a1a364e1fdcd 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -5189,6 +5189,36 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf) > return folio_prealloc(vma->vm_mm, vma, vmf->address, true); > } > > +void map_anon_folio_pte_nopf(struct folio *folio, pte_t *pte, > + struct vm_area_struct *vma, unsigned long addr, > + bool uffd_wp) > +{ > + unsigned int nr_pages = folio_nr_pages(folio); > + pte_t entry = folio_mk_pte(folio, vma->vm_page_prot); > + > + entry = pte_sw_mkyoung(entry); > + > + if (vma->vm_flags & VM_WRITE) > + entry = pte_mkwrite(pte_mkdirty(entry), vma); > + if (uffd_wp) > + entry = pte_mkuffd_wp(entry); > + > + folio_ref_add(folio, nr_pages - 1); > + folio_add_new_anon_rmap(folio, vma, addr, RMAP_EXCLUSIVE); > + folio_add_lru_vma(folio, vma); > + set_ptes(vma->vm_mm, addr, pte, entry, nr_pages); > + update_mmu_cache_range(NULL, vma, addr, pte, nr_pages); > +} > + > +static void map_anon_folio_pte_pf(struct folio *folio, pte_t *pte, > + struct vm_area_struct *vma, unsigned long addr, > + unsigned int nr_pages, bool uffd_wp) > +{ > + map_anon_folio_pte_nopf(folio, pte, vma, addr, uffd_wp); > + add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages); > + count_mthp_stat(folio_order(folio), MTHP_STAT_ANON_FAULT_ALLOC); > +} One thing: You can also void passing in "nr_pages" here, especially when you query the order below, and simply do unsigned int order = folio_order(folio); map_anon_folio_pte_nopf(folio, pte, vma, addr, uffd_wp); add_mm_counter(vma->vm_mm, MM_ANONPAGES, 1U << order); count_mthp_stat(order, MTHP_STAT_ANON_FAULT_ALLOC); Apart from that Acked-by: David Hildenbrand (Arm) -- Cheers, David