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 9D2CDF483E3 for ; Mon, 23 Mar 2026 18:32:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C3DEA6B0092; Mon, 23 Mar 2026 14:32:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id BC81E6B0095; Mon, 23 Mar 2026 14:32:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A41216B0096; Mon, 23 Mar 2026 14:32:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 8F6DA6B0092 for ; Mon, 23 Mar 2026 14:32:14 -0400 (EDT) Received: from smtpin06.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2E075160876 for ; Mon, 23 Mar 2026 18:32:14 +0000 (UTC) X-FDA: 84578172588.06.79208C9 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf09.hostedemail.com (Postfix) with ESMTP id 67BE914001A for ; Mon, 23 Mar 2026 18:32:12 +0000 (UTC) Authentication-Results: imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=vRRWBHBL; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf09.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1774290732; a=rsa-sha256; cv=none; b=YzdN2egLKRiowVAl3KJJsZbaRC4E4XdUBadcjb0I7FWJZHPeoiY4ASNFuBSktF23NDcEdl r2z1hG0gJBdWGSSxAF1OYwxs9APWO148m1uC6eqgK1FDoz4GTPF37TjiNHDF/WmOjlCc4x 33SwO2cbWePLHLCUS9UxYIXzwLB2xws= ARC-Authentication-Results: i=1; imf09.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=vRRWBHBL; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf09.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1774290732; 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=r3FEdx4cl7hZyyKk+NpULiS9hUxyw3Glf8bv5rv0lIU=; b=3JIF46W2hc68BRVBLZOKvBjiHQSHTg6Jwy220zCn9AGJ78KAxb2K2++PFJUJn0esS8XBNE 26yOLdqC/9pczd0ppQ9pb7R/TqyNyS3WH+/pxTnurYaHKg0WUfFzHb+/Xu/gSHVyg36/BW bcoN+cnQ/BbQZ1o4Ccb0/AaYORKR9oc= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id C1CF86012B; Mon, 23 Mar 2026 18:32:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 103D0C4CEF7; Mon, 23 Mar 2026 18:31:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774290730; bh=sotfvo0nesaSqmF8KoCTyd8MGYvSoQDCsni9TVbHztU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=vRRWBHBLoOcTBUkF+rhoE7Rq4ConSk0Rgcrmkzw4YpeHsu7GHVxSU+9xzFXPbOY5i u0bAdR1IYL2lSje2Hro7d5AOekw2HXFGZ5LaJSQpGRh2R/vbkvzdqgL+J47uDWMz/+ KFn7D0EB1cQxfFTDPfXur1Gjb858d3o0L8cWM3fNwCDKgzKWrqC0rplNwEmksAbSPu ZS/lz7HhEE979x/coOh2lXPJitq0izgvM2ECa5Pxhd4/XspzBs6aGxUsjVWxPxxi5n PNI8xSolmqCXpQMOQFSD2aRJO2mcLziuJFRjSC8Ugh6XmqXhU8DPyrveb+XFeCxWhL VUfOOfL58/8fg== Message-ID: <76f14d3e-c8fb-4380-9d12-2375f199b53f@kernel.org> Date: Mon, 23 Mar 2026 19:31:36 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v11 04/16] mm/gup: drop secretmem optimization from gup_fast_folio_allowed To: "Kalyazin, Nikita" , "kvm@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.linux.dev" , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "bpf@vger.kernel.org" , "linux-kselftest@vger.kernel.org" , "kernel@xen0n.name" , "linux-riscv@lists.infradead.org" , "linux-s390@vger.kernel.org" , "loongarch@lists.linux.dev" , "linux-pm@vger.kernel.org" Cc: "pbonzini@redhat.com" , "corbet@lwn.net" , "maz@kernel.org" , "oupton@kernel.org" , "joey.gouly@arm.com" , "suzuki.poulose@arm.com" , "yuzenghui@huawei.com" , "catalin.marinas@arm.com" , "will@kernel.org" , "seanjc@google.com" , "tglx@kernel.org" , "mingo@redhat.com" , "bp@alien8.de" , "dave.hansen@linux.intel.com" , "x86@kernel.org" , "hpa@zytor.com" , "luto@kernel.org" , "peterz@infradead.org" , "willy@infradead.org" , "akpm@linux-foundation.org" , "lorenzo.stoakes@oracle.com" , "vbabka@kernel.org" , "rppt@kernel.org" , "surenb@google.com" , "mhocko@suse.com" , "ast@kernel.org" , "daniel@iogearbox.net" , "andrii@kernel.org" , "martin.lau@linux.dev" , "eddyz87@gmail.com" , "song@kernel.org" , "yonghong.song@linux.dev" , "john.fastabend@gmail.com" , "kpsingh@kernel.org" , "sdf@fomichev.me" , "haoluo@google.com" , "jolsa@kernel.org" , "jgg@ziepe.ca" , "jhubbard@nvidia.com" , "peterx@redhat.com" , "jannh@google.com" , "pfalcato@suse.de" , "skhan@linuxfoundation.org" , "riel@surriel.com" , "ryan.roberts@arm.com" , "jgross@suse.com" , "yu-cheng.yu@intel.com" , "kas@kernel.org" , "coxu@redhat.com" , "kevin.brodsky@arm.com" , "ackerleytng@google.com" , "yosry@kernel.org" , "ajones@ventanamicro.com" , "maobibo@loongson.cn" , "tabba@google.com" , "prsampat@amd.com" , "wu.fei9@sanechips.com.cn" , "mlevitsk@redhat.com" , "jmattson@google.com" , "jthoughton@google.com" , "agordeev@linux.ibm.com" , "alex@ghiti.fr" , "aou@eecs.berkeley.edu" , "borntraeger@linux.ibm.com" , "chenhuacai@kernel.org" , "dev.jain@arm.com" , "gor@linux.ibm.com" , "hca@linux.ibm.com" , "palmer@dabbelt.com" , "pjw@kernel.org" , "shijie@os.amperecomputing.com" , "svens@linux.ibm.com" , "thuth@redhat.com" , "wyihan@google.com" , "yang@os.amperecomputing.com" , "Jonathan.Cameron@huawei.com" , "Liam.Howlett@oracle.com" , "urezki@gmail.com" , "zhengqi.arch@bytedance.com" , "gerald.schaefer@linux.ibm.com" , "jiayuan.chen@shopee.com" , "lenb@kernel.org" , "osalvador@suse.de" , "pavel@kernel.org" , "rafael@kernel.org" , "vannapurve@google.com" , "jackmanb@google.com" , "aneesh.kumar@kernel.org" , "patrick.roy@linux.dev" , "Thomson, Jack" , "Itazuri, Takahiro" , "Manwaring, Derek" , Vlastimil Babka , Dan Williams , Alistair Popple References: <20260317141031.514-1-kalyazin@amazon.com> <20260317141031.514-5-kalyazin@amazon.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: <20260317141031.514-5-kalyazin@amazon.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Stat-Signature: 159fxdu4syfas8m3h3dktyw6cjxsdk16 X-Rspamd-Queue-Id: 67BE914001A X-Rspam-User: X-Rspamd-Server: rspam03 X-HE-Tag: 1774290732-948985 X-HE-Meta: U2FsdGVkX1+gOxA9Q/LPjT/WU+tOY8YMglWvbNqaYqHKo5UyxPnkpBPc/23n5NDb3+bgAx1ICLf1yIQN4MtBaWONaIBC+U0fsFTudJPhDxIpzvIn5jiD7KPi1Ga8SdeEuampNxvzkLtTwdU9Fy/8tmphzVxxMK31WVt6s2aePwuODGjTeXPAyXlhJTjbNJWn/Ds0e3MqHbz90R9UHt0GjMoZbScikbaJz1JNfvn00OBguBSdaIYEmKB9wCdBuvMMfKjlmxUq6ZLhGdWXyI32Oljlxn4lWnjLYXUGBMLPykq+sx7Lpqb1l2FFhbEZPpF6w9e6u7066ICAyWP/+ZzCVH/Yl8SgUc1PEiDv/4bE0EHThdrT994gTroHMYA0o0yapb0z72Pa4P+OyzqNXOQp0FaQOL9p68zjMA4Sq/bPUOAnVyKnqkquxQLurkFMaHPWzcpzyqPHt/yMYnVVgm4Ujmycmf4MhXwl1w0+wyKofnnqj/ac3RHhp7fsTwBNXiddrg4CYlEFk4N6/wDGJGYDWSlrQbhrp4zubZwLlYO3rJssd+XJTiZa8Vb4CioxufP+xmRdKbMp8pxvFPtA5icQXvaBLr4hQHAnesICRHBnMMhxajY1duZ4AZuz5zdgrlwPO3nSIh4VPY8vE5N3wurxucDlH1bNJ4gMf5DppkinJ+DvYoU5i1toTuZfTmLqMPwGWnn4NguvHzsc8nXdGCXN0TwKKdGaLFApoENZL28o4X70hTK6ZthAZMPgWSBl7ApoFcpZSoywWa9r9D0KXY/XfPpX44TB5H69IFbLbmtz5Xpu53SVLtR6/ayM0qdGmejX70mfjx+lX4GVJIdrVuoOzObLglY41fi3hOfNRUuzsztVsN1whEYN8qt1u+0ZJRlZ+wJVunhFz6Zzjw2aIH6j4n16NxT8RHWO5w8Cv1yN1TGk1zjcOXYMXs+6mTsAiXJpHfHnD9cv8Mvi5Ub7S/w XUvWobRX dRls32Tv2nX5OO6mUE6QysUdXbnXRRJXp0JQN6mqrccndHquUDj3iDS8UDDxYI5kjJEnJ+Vi5PSdtP+a4IVWMBi3OpjWbKCvTIJN8nMuXLEtMsWEtc+Jsv0Hmpx271uwIeNu9fKvb5UPH0ryIS/l5xA3es8eMWKn6pCPxuVvAHb6AXSDfENqOcfdg+1mTHsBZDxP9fWpAoWKsc7cT441IpeQIzH1cTWwwUIjojPv+1gUTlYZUv6qEwhEszomtAcg+DkCcjxg5mqjcB9MXsD9qzbAqaiWRdYO3DLg7S0F0l8IEI8DeQBBd3wYYs0k0cR3iNrssh7+aEqS1uecq0pl6g5XnRatvnUz8kHzvk3tD8tRL35yzpXt4kBRp5xDH0uXDKQogou6IR3XW8I0KpOzreeMcVtk8AA0NEnbo0Io4b4to4JueSv/jqenuhLkaIdJXOelKD7UNGIyBbszZv9HIrhMgew== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 3/17/26 15:11, Kalyazin, Nikita wrote: > From: Patrick Roy > > This drops an optimization in gup_fast_folio_allowed() where > secretmem_mapping() was only called if CONFIG_SECRETMEM=y. secretmem is > enabled by default since commit b758fe6df50d ("mm/secretmem: make it on > by default"), so the secretmem check did not actually end up elided in > most cases anymore anyway. > > This is in preparation of the generalization of handling mappings where > direct map entries of folios are set to not present. Currently, > mappings that match this description are secretmem mappings > (memfd_secret()). Later, some guest_memfd configurations will also fall > into this category. > > Signed-off-by: Patrick Roy > Acked-by: Vlastimil Babka > Acked-by: David Hildenbrand (Red Hat) > Signed-off-by: Nikita Kalyazin > --- > mm/gup.c | 11 +---------- > 1 file changed, 1 insertion(+), 10 deletions(-) > > diff --git a/mm/gup.c b/mm/gup.c > index 8e7dc2c6ee73..5856d35be385 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -2739,7 +2739,6 @@ static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags) > { > bool reject_file_backed = false; > struct address_space *mapping; > - bool check_secretmem = false; > unsigned long mapping_flags; > > /* > @@ -2751,14 +2750,6 @@ static bool gup_fast_folio_allowed(struct folio *folio, unsigned int flags) > reject_file_backed = true; > > /* We hold a folio reference, so we can safely access folio fields. */ > - > - /* secretmem folios are always order-0 folios. */ > - if (IS_ENABLED(CONFIG_SECRETMEM) && !folio_test_large(folio)) > - check_secretmem = true; > - > - if (!reject_file_backed && !check_secretmem) > - return true; > - The AI review says that this will force all small folios through the mapping check (which we obviously need later :) ). It brings up two cases where page->mapping is not set up: 1) ZONE_DEVICE pages (like Device DAX and PCI P2PDMA) 2) large shmem folios in the swap cache 2) doesn't make sense, because the folio cannot be mapped in user space when that happens. I am also skeptical about 1), especially as large folios are also supported for device dax and would be problematic here. __dev_dax_pte_fault() clearly sets folio->mapping through dax_set_mapping(). If 1) is ever a case we could allow them by checking for folio_is_zone_device(). But I am not sure if that is really required. Sounds weird. -- Cheers, David