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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21B91C2BA1A for ; Fri, 21 Jun 2024 09:10:22 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 4D2786B018E; Fri, 21 Jun 2024 05:10:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 434888D00DB; Fri, 21 Jun 2024 05:10:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1C54A8D014C; Fri, 21 Jun 2024 05:10:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id EC6FF8D00DB for ; Fri, 21 Jun 2024 05:10:20 -0400 (EDT) Received: from smtpin22.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 881BB1A0C32 for ; Fri, 21 Jun 2024 09:10:20 +0000 (UTC) X-FDA: 82254324600.22.F4BD7D8 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf02.hostedemail.com (Postfix) with ESMTP id 22C7D80019 for ; Fri, 21 Jun 2024 09:10:17 +0000 (UTC) Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=b0qIaDK5; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf02.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1718961010; a=rsa-sha256; cv=none; b=FTHDde52SI0UgCdGg/0x3sO7vvW0lwWGXDsyx6l1bSY8FtlT+atBC2u/Q31JAe8WDF8LTs HTLJFBWf3Uv9iwYi5zXT/69AKXBFzfXx0werHLe6NiILco/7EBZoYzvuaTIJ0BV4WBagJ9 9JfymYT5F+Ooq0/I7p9qgW8JMRELFmc= ARC-Authentication-Results: i=1; imf02.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=b0qIaDK5; dmarc=pass (policy=none) header.from=redhat.com; spf=pass (imf02.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1718961010; 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=gYejcBX91Zhx9zBhD+bnNzE1FrYHOgpUiQ+y0qItqUU=; b=ULPFIdNSLkWhwnRlU9wnUvLDImVd4mgaUb60L6hqIj0p4p9KHz57knSC660ElDJoZRLWXV lgWZtuEshXOAulpOm9bFYt2emAOA+OPDfYoFlcOumBu5Y2CqlsPjlYj0oyWG/5tV+tS2O0 3CzHFy3clIxV8n0FtSl44aE4DP23dVc= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1718961017; h=from:from: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:autocrypt:autocrypt; bh=gYejcBX91Zhx9zBhD+bnNzE1FrYHOgpUiQ+y0qItqUU=; b=b0qIaDK5qkn14rmCiJIk+9GJRyGnxL9Eju95bhBmMZO7DvgnwlkApmx6j/HCO8l/wAW8ry uujWNl6XVlohN3cikh7MBrT/hZPO+a6M/30QP0NxLFYFAZa86sHE36cC3sFlGJRaFYueW5 9AgVeo/zBGeR5YQWCWnvqUx/vR2yaXY= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-489-MeMaD15fNRG9esPL2XDSZA-1; Fri, 21 Jun 2024 05:10:15 -0400 X-MC-Unique: MeMaD15fNRG9esPL2XDSZA-1 Received: by mail-wm1-f71.google.com with SMTP id 5b1f17b1804b1-4247d49a373so13162865e9.1 for ; Fri, 21 Jun 2024 02:10:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718961014; x=1719565814; h=content-transfer-encoding:in-reply-to:organization:autocrypt :content-language:from:references:cc:to:subject:user-agent :mime-version:date:message-id:x-gm-message-state:from:to:cc:subject :date:message-id:reply-to; bh=gYejcBX91Zhx9zBhD+bnNzE1FrYHOgpUiQ+y0qItqUU=; b=YMgKZR8fypS6I0upTp0oHvfm3vXUBgF4k+ivzQ1TflMC0htx10W8OyCvo4nvhDEWm7 tAOf77h7MThza9We4IeMu82RAsFwEOyEih5rLg2J4t6oljTjBws1B74UnD4oMmV/MEHs 9xdsrGTul9l6hJS1TayBimiEALuH9tT4BkHHxIyng/d1bNfisHulyIOp3mJf7yWsJ0cD 395TyB8QxkdybudLr6neQ+EfHUBMBAB/J4s7UBFzNULRpZaG7hA8uKblhDrxU8u9fEhe nu/u4ilD97ZDNllAdUEhZXrBWTfhMBEKrCVPoM+RoAvtZVnfTN2XQDgMnX5k3IvwIE5Y fqIQ== X-Forwarded-Encrypted: i=1; AJvYcCXhQh07QIZBJB7yZgJwEP3i30eGh3mb73ljlI8hrW94nf4jR5r2UiOAY7yxG979/TBhQ6NtrCVBG3qToda3vvbYfig= X-Gm-Message-State: AOJu0YxGF3q2RtwEHpEaGii8QiKJ1goFrrrc04/4q2W+7lnOTxFTOqMd 18Xr/5cTg2iFmfS73xCggJItme2qoMcW2ffmbjQ6PTcRsELcHAqIoXXvVujzh54AceH7xld+QbE 369xcwGlbK+UKCruLaqUVdSvO3mesWxKgzZiRA6KUvQ9xYZuv X-Received: by 2002:a05:600c:1d05:b0:424:7780:ffc3 with SMTP id 5b1f17b1804b1-424778101b9mr48375295e9.5.1718961014329; Fri, 21 Jun 2024 02:10:14 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGU90oPuoG7ZEQHn11qd8u510OI3LfnmEaaKKjLepvgJT1/MBU6PiG7DAfnb5yOTq9erHiYHw== X-Received: by 2002:a05:600c:1d05:b0:424:7780:ffc3 with SMTP id 5b1f17b1804b1-424778101b9mr48375035e9.5.1718961013836; Fri, 21 Jun 2024 02:10:13 -0700 (PDT) Received: from ?IPV6:2003:cb:c725:e600:4063:2059:fd18:9d65? (p200300cbc725e60040632059fd189d65.dip0.t-ipconnect.de. [2003:cb:c725:e600:4063:2059:fd18:9d65]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-366383f6d16sm1140229f8f.3.2024.06.21.02.10.12 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 21 Jun 2024 02:10:13 -0700 (PDT) Message-ID: <8e9436f2-6ebb-4ce1-a44f-2a941d354e2a@redhat.com> Date: Fri, 21 Jun 2024 11:10:12 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH RFC 0/5] mm/gup: Introduce exclusive GUP pinning To: Fuad Tabba , David Rientjes Cc: Sean Christopherson , Jason Gunthorpe , John Hubbard , Elliot Berman , Andrew Morton , Shuah Khan , Matthew Wilcox , maz@kernel.org, kvm@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, pbonzini@redhat.com References: <20240618-exclusive-gup-v1-0-30472a19c5d1@quicinc.com> <7fb8cc2c-916a-43e1-9edf-23ed35e42f51@nvidia.com> <14bd145a-039f-4fb9-8598-384d6a051737@redhat.com> <20240619115135.GE2494510@nvidia.com> <4c8b81a0-3a76-4802-875f-f26ff1844955@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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 B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwZgEEwEIAEICGwMGCwkIBwMCBhUIAgkKCwQW AgMBAh4BAheAAhkBFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl8Ox4kFCRKpKXgACgkQTd4Q 9wD/g1oHcA//a6Tj7SBNjFNM1iNhWUo1lxAja0lpSodSnB2g4FCZ4R61SBR4l/psBL73xktp rDHrx4aSpwkRP6Epu6mLvhlfjmkRG4OynJ5HG1gfv7RJJfnUdUM1z5kdS8JBrOhMJS2c/gPf wv1TGRq2XdMPnfY2o0CxRqpcLkx4vBODvJGl2mQyJF/gPepdDfcT8/PY9BJ7FL6Hrq1gnAo4 3Iv9qV0JiT2wmZciNyYQhmA1V6dyTRiQ4YAc31zOo2IM+xisPzeSHgw3ONY/XhYvfZ9r7W1l pNQdc2G+o4Di9NPFHQQhDw3YTRR1opJaTlRDzxYxzU6ZnUUBghxt9cwUWTpfCktkMZiPSDGd KgQBjnweV2jw9UOTxjb4LXqDjmSNkjDdQUOU69jGMUXgihvo4zhYcMX8F5gWdRtMR7DzW/YE BgVcyxNkMIXoY1aYj6npHYiNQesQlqjU6azjbH70/SXKM5tNRplgW8TNprMDuntdvV9wNkFs 9TyM02V5aWxFfI42+aivc4KEw69SE9KXwC7FSf5wXzuTot97N9Phj/Z3+jx443jo2NR34XgF 89cct7wJMjOF7bBefo0fPPZQuIma0Zym71cP61OP/i11ahNye6HGKfxGCOcs5wW9kRQEk8P9 M/k2wt3mt/fCQnuP/mWutNPt95w9wSsUyATLmtNrwccz63XOwU0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAHCwXwEGAEIACYCGwwWIQQb2cqtc1xMOkYN/MpN3hD3 AP+DWgUCXw7HsgUJEqkpoQAKCRBN3hD3AP+DWrrpD/4qS3dyVRxDcDHIlmguXjC1Q5tZTwNB boaBTPHSy/Nksu0eY7x6HfQJ3xajVH32Ms6t1trDQmPx2iP5+7iDsb7OKAb5eOS8h+BEBDeq 3ecsQDv0fFJOA9ag5O3LLNk+3x3q7e0uo06XMaY7UHS341ozXUUI7wC7iKfoUTv03iO9El5f XpNMx/YrIMduZ2+nd9Di7o5+KIwlb2mAB9sTNHdMrXesX8eBL6T9b+MZJk+mZuPxKNVfEQMQ a5SxUEADIPQTPNvBewdeI80yeOCrN+Zzwy/Mrx9EPeu59Y5vSJOx/z6OUImD/GhX7Xvkt3kq Er5KTrJz3++B6SH9pum9PuoE/k+nntJkNMmQpR4MCBaV/J9gIOPGodDKnjdng+mXliF3Ptu6 3oxc2RCyGzTlxyMwuc2U5Q7KtUNTdDe8T0uE+9b8BLMVQDDfJjqY0VVqSUwImzTDLX9S4g/8 kC4HRcclk8hpyhY2jKGluZO0awwTIMgVEzmTyBphDg/Gx7dZU1Xf8HFuE+UZ5UDHDTnwgv7E th6RC9+WrhDNspZ9fJjKWRbveQgUFCpe1sa77LAw+XFrKmBHXp9ZVIe90RMe2tRL06BGiRZr jPrnvUsUUsjRoRNJjKKA/REq+sAnhkNPPZ/NNMjaZ5b8Tovi8C0tmxiCHaQYqj7G2rgnT0kt WNyWQQ== Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 22C7D80019 X-Stat-Signature: xqemkpb9of3urpgztwi8cwxq19w7sd7k X-Rspam-User: X-HE-Tag: 1718961017-602658 X-HE-Meta: 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 Vb+DWUOY CItjzl0GpoWkOW3rN/7jX0hY93/A8TuHfWbZQqdWc0Y1D7wCc/PkkgVWN2xtmcmJgAtzU7Kq/5TcU3ClvnFp53PgozJt5hH+Lqj+GunsG+yDKvcUfew1UZ69m3qLbu43MKLxQFPnJdoMEw8iLuGKRljzQn23mEgC5Ue6F4bCQjKvEJu2uD9M5kHfGKlSxOPtXbq5vnWpkwSDtGyBYyvQu0w/xZJoZfERD6p/k6sUCyqFuy+suyB7tBTKYJMzRz2xDhW/xSJQu2PoUgfJR+uiZHhSo/jgpMasW2arT7m5V0N33e/UEkdShDcw6pLOom+rIpoF1dIaOCyfRlBorhU+7QQLJBZG7MQDlIM7Te62nd1vV1rNXcoHJzDz9Xk6DEuC9SxZfXEFTH6TwSfjUUkqNNG9FfifOxgVCjquwa1EWK81Jyj0Mbi26SsKf6b3CsWy6cyuEncH6ZZiNEwM= 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 21.06.24 10:54, Fuad Tabba wrote: > Hi David, > > On Fri, Jun 21, 2024 at 9:44 AM David Hildenbrand wrote: >> >>>> Again from that thread, one of most important aspects guest_memfd is that VMAs >>>> are not required. Stating the obvious, lack of VMAs makes it really hard to drive >>>> swap, reclaim, migration, etc. from code that fundamentally operates on VMAs. >>>> >>>> : More broadly, no VMAs are required. The lack of stage-1 page tables are nice to >>>> : have; the lack of VMAs means that guest_memfd isn't playing second fiddle, e.g. >>>> : it's not subject to VMA protections, isn't restricted to host mapping size, etc. >>>> >>>> [1] https://lore.kernel.org/all/Zfmpby6i3PfBEcCV@google.com >>>> [2] https://lore.kernel.org/all/Zg3xF7dTtx6hbmZj@google.com >>> >>> I wonder if it might be more productive to also discuss this in one of >>> the PUCKs, ahead of LPC, in addition to trying to go over this in LPC. >> >> I don't know in which context you usually discuss that, but I could >> propose that as a topic in the bi-weekly MM meeting. >> >> This would, of course, be focused on the bigger MM picture: how to mmap, >> how how to support huge pages, interaction with page pinning, ... So >> obviously more MM focused once we are in agreement that we want to >> support shared memory in guest_memfd and how to make that work with core-mm. >> >> Discussing if we want shared memory in guest_memfd might be betetr >> suited for a different, more CC/KVM specific meeting (likely the "PUCKs" >> mentioned here?). > > Sorry, I should have given more context on what a PUCK* is :) It's a > periodic (almost weekly) upstream call for KVM. > > [*] https://lore.kernel.org/all/20230512231026.799267-1-seanjc@google.com/ > > But yes, having a discussion in one of the mm meetings ahead of LPC > would also be great. When do these meetings usually take place, to try > to coordinate across timezones. It's Wednesday, 9:00 - 10:00am PDT (GMT-7) every second week. If we're in agreement, we could (assuming there are no other planned topics) either use the slot next week (June 26) or the following one (July 10). Selfish as I am, I would prefer July 10, because I'll be on vacation next week and there would be little time to prepare. @David R., heads up that this might become a topic ("shared and private memory in guest_memfd: mmap, pinning and huge pages"), if people here agree that this is a direction worth heading. -- Cheers, David / dhildenb