From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C9FAFEDF170 for ; Fri, 13 Feb 2026 15:08:45 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4115C6B0088; Fri, 13 Feb 2026 10:08:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 3F2A36B008A; Fri, 13 Feb 2026 10:08:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2EB7A6B008C; Fri, 13 Feb 2026 10:08:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 1BC346B0088 for ; Fri, 13 Feb 2026 10:08:45 -0500 (EST) Received: from smtpin28.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id BE3591C5BE for ; Fri, 13 Feb 2026 15:08:44 +0000 (UTC) X-FDA: 84439765368.28.F94F48B Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf17.hostedemail.com (Postfix) with ESMTP id D85AF4000C for ; Fri, 13 Feb 2026 15:08:42 +0000 (UTC) Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sK1IjiSC; spf=pass (imf17.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-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1770995323; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=nu2gpGxkGLyhK46cAjEX87LSAqSH3W+w/doPxW+RIKY=; b=cgtUINFm5ifAsBLzax6R5teuPboM3wefZKTRrjlIbSg8/mSOb+6dUEUnZpxVUjeNFLX09c Svxl+z+9Pa1CN1LwuTAYGO7Ed6p6lteiTsfsaWN4dBcnxFSOmA3R57lYVZ5Uw/V+ySyNnj re4z/EZRqb1XMu2tugMQ/zDtpQnezwk= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1770995323; a=rsa-sha256; cv=none; b=LX+ZkkCQqd4B3SwlySaMlC7l2bgQ0k2PSZLfJsGQHuyEz5Ha/KHfcnknvPrvY5byUHokYV oP7Izi2nadyvVKBmicQm12Go9/cdEIdbNxrsFXC0tiz6pg8lWj6bGgbv14IXldjuuMK+P/ Az/lxYDtMmgQXKJMS1Eikd2Ld0G53Fg= ARC-Authentication-Results: i=1; imf17.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=sK1IjiSC; spf=pass (imf17.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 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id E2CA242E46; Fri, 13 Feb 2026 15:08:41 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBF97C116C6; Fri, 13 Feb 2026 15:08:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770995321; bh=GXBtj1qNC6Jblz3dIZAJPiDoGI3O8kR+BUHee7Igrxc=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=sK1IjiSCmE0y7Sh4IMcY8/2LLoIK7UQ4n8wkOCBdWaLEvd3rdW70ws1cCiyAlM7Jv Bf6VvLoH4l6aMpSvSl6TJUVgHLQ4/w1vHBNwFj8hko+9w/YTq5RyAcMu0a2UrrHN1w SaViNgvq9gIUqvJy3e2hbju3fiYTT59ttIJ7gcuCPIXvymCRIrQM4M24jfBK0S97xb n10y+E1+4yXB1aUwPVma3ihjViDfZ6g6Pl2izTuq4eD9qtGranD2KH6rrfKFye5BTs /lMJH39wQmgFZehRfcld42W49t/HDxsFR7jyOpR3vA0pgDS5hXAVkbwirDoMK8w5Ru cy6/AeapB5wgw== Message-ID: Date: Fri, 13 Feb 2026 16:08:34 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH] mm: only set fault addrsss' access bit in do_anonymous_page To: Wenchao Hao Cc: Andrew Morton , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260210043456.2137482-1-haowenchao22@gmail.com> <5c4d773c-e3e7-4a71-b250-91701cbdd4a2@kernel.org> <201fcbb4-c43c-406c-ad54-f2c9301c12b0@kernel.org> 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; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: D85AF4000C X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: pkafqt394bjqj69ypgq3nz1r9kphtj44 X-HE-Tag: 1770995322-922707 X-HE-Meta: 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 7kSYU7Lx ntpqChJpIAi5RzUv46SYPq6vWHqsh81AiVM6ytPXC1gv7hM4uW6JVzRhmaIvYBEyngi3UrfB5F5kn15QaW3pG1lCPHHBpqGi7xOHiqQ/uL2liQvORSs2ITi/+6n6L1GjA0XRGhUD5j5YoUjO7qsIUDPwNYpqhza1xnmDLdF7XWAX5DiXq6ODIcQmwBshgLGqeXxkdnXKtnJ/dZwdmYH0jqh6miiStQkSORIWiIS9EuOqfQ2qTcyHJu4ofWYB1BQ2I5zeS7AyqSJ5YDKIdzxoDw6zoR8TifGEldHIg2ZLk77lBn6zAbwqm0Zwqu4cIqjGB5bZXUxHyghny6MIqdp93z0x//bk6rM0nQTnP X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2/13/26 15:52, Wenchao Hao wrote: > On Fri, Feb 13, 2026 at 5:08 PM David Hildenbrand (Arm) > wrote: >> >> On 2/13/26 10:02, Wenchao Hao wrote: >>> On Thu, Feb 12, 2026 at 4:54 PM David Hildenbrand (Arm) >>> wrote: >>> >>> Apologies for the delayed reply – I was just writing a demo to verify the >>> approach you mentioned. >>> >>> Using the CONFIG_DEBUG_KERNEL compile-time macro to isolate this feature >>> is indeed an excellent idea. >>> >>> However, in engineering practice, it requires recompiling and >>> replacing the kernel, >>> which can be cumbersome. Could we instead use a dynamic switch to control >>> whether scan for zero-filled pages when reading /proc/[pid]/smaps? >> >> Maybe a kernel cmdline option could do? > Kernel command line parameters can meet our requirements. > >> Selectively enabling it for some PIDs only is not really possible, but also, maybe it's not really needed. > Yes, it is unnecessary to do that. > > By the way, will you send a new patch for this, or shall I take care of it? You :) -- Cheers, David