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bh=JxHcRJ/uAa2Q++f+570ob3TPntbfaPHmCgZ1Tbd71eM=; b=FkH6dAzcNnA8QXg5qBgvM69WD5lw6Lk3ey4wgGIjs37/QXV54crqRF1ewMSsD29ezysSLF yjiF6W4GQHAb7FDRVcmkhbyMKbygDbbUJioXVu6ZzSlVy3nbFwMxd4z5yugR4ol2rRsH0E 2CEeUsoXzxZCBqLk65gB7sCIF0vWRwQ= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=WR+M1DMJ; spf=pass (imf22.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id DDE6660098; Fri, 26 Jun 2026 08:14:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 07B9F1F000E9; Fri, 26 Jun 2026 08:13:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782461640; bh=JxHcRJ/uAa2Q++f+570ob3TPntbfaPHmCgZ1Tbd71eM=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=WR+M1DMJgMM4t2+ge79esnF02O9RFDzaN6Hg8/fc7y546zi/NwZiYes6VYI3/aBQZ 6+Cw59NKIvzfa1B4ozxZkKbjLc7j6HSSYkNPdvMHm/WwrLhlD5u9pyfmcL0iADABaB 0k7M86I1isVsPIC/MaNzA3UC2A+FUq4nADUmz7WVOj0d7V9Yq8Xvfmajw9/fdd05cm xlI/KfbpzFD5DqWZ+Yj7UZzacj+kd6zs8xhQtc8COgTHV2DdXtZYq8rB7rSxanFLXF rOtRMkHz3+SHSsoE129fOsCYrbYAdXchLobLPk4zHJuj+nXEJL1GhbDfXtv74uhd5A pheE1SPsjoetw== Message-ID: Date: Fri, 26 Jun 2026 10:13:53 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2] fs/proc: fix KPF_KSM reported for all anonymous pages To: Jinjiang Tu , akpm@linux-foundation.org, ziy@nvidia.com, luizcap@redhat.com, willy@infradead.org, linmiaohe@huawei.com, svetly.todorov@memverge.com, xu.xin16@zte.com.cn, chengming.zhou@linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Cc: wangkefeng.wang@huawei.com, sunnanyong@huawei.com References: <20260626013252.2846774-1-tujinjiang@huawei.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: <20260626013252.2846774-1-tujinjiang@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: u55uknrb75x3uguf8h1q11d9dg6hnoho X-Rspamd-Queue-Id: 737ACC0005 X-Rspamd-Server: rspam06 X-HE-Tag: 1782461641-117067 X-HE-Meta: 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 Edbaoips TFKDlLUgJzqpxCzqbAv0cJmlKTRiy69lxlpYBXX6LkTWE4wRvmApuWDL3wnfuxnuMA7aqdD+ZAU2IOJTMelxIoXrz7SlNjxgPP4DjlGuvZjhyis1WjIE2BIocAucT5eyZTmeE1NjvMYDDs4ud0Y/EDp1gjcjiXpjZ4+JOoYE6nj1a1LFrYphso0cs3GlH3kN9glWMC69zFywkr7QCd+rRIb8o3qowtVpECMqYMCUyH+RAfoU627TONEHRKy4VybdxF3PPr0lZYiMVm22lrfOfrvhipGyBLqjYBfW7LwGK/w7PO+txecsG5L9BGD+s8i7282htenZA0dFfph/apYHaGXgOswhAEapxvxAk Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 6/26/26 03:32, Jinjiang Tu wrote: > Reading /proc/kpageflags for any anonymous page returns KPF_KSM set, even > when KSM is not in use. As a result, tools misclassify all anonymous pages > as KSM merged. > > In stable_page_flags(), if the page is anonymous, then use (mapping & > FOLIO_MAPPING_KSM) check to identify if the anonymous page is KSM page. > However, FOLIO_MAPPING_KSM is FOLIO_MAPPING_ANON | FOLIO_MAPPING_ANON_KSM, > (mapping & FOLIO_MAPPING_KSM) check returns true for all nonymous pages. > > To fix it, use FOLIO_MAPPING_ANON_KSM instead. > > Fixes: dee3d0bef2b0 ("proc: rewrite stable_page_flags()") > Signed-off-by: Jinjiang Tu > --- With spelling fix Acked-by: David Hildenbrand (Arm) And I'd appreciate if someone could look into cleaning up the code to switch back to folio helpers now that we have folio+page snapshots. -- Cheers, David