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 3672ED6AAFE for ; Thu, 2 Apr 2026 19:33:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 5E4B06B0005; Thu, 2 Apr 2026 15:33:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 595C86B0089; Thu, 2 Apr 2026 15:33:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 45DA76B008A; Thu, 2 Apr 2026 15:33:06 -0400 (EDT) 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 2FF836B0005 for ; Thu, 2 Apr 2026 15:33:06 -0400 (EDT) Received: from smtpin23.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id B67D11B8B6F for ; Thu, 2 Apr 2026 19:33:05 +0000 (UTC) X-FDA: 84614613930.23.059886B Received: from mx0b-00364e01.pphosted.com (mx0b-00364e01.pphosted.com [148.163.139.74]) by imf23.hostedemail.com (Postfix) with ESMTP id 33326140012 for ; Thu, 2 Apr 2026 19:33:03 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=columbia.edu header.s=pps01 header.b=pBQ67VJ4; spf=pass (imf23.hostedemail.com: domain of tz2294@columbia.edu designates 148.163.139.74 as permitted sender) smtp.mailfrom=tz2294@columbia.edu; dmarc=pass (policy=none) header.from=columbia.edu ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1775158383; 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=1WmaGc9Te9yz0Zibs0J92PxP2axqg3Ucqwb44WM0s3g=; b=tnXA1WxKUqxmaeT88PA5xijuPPu6dHkZaQkkX0BXl6CrTTjxd17GkOpYbxNCNiU7zNhlcR k8z9rmZisZ+Su10KxDk31iKC5EXZEzjlRJspOUJUe5jvXLOJCvNYIIo7BAE3TB+L+sRmuh 4Aop1DPECqfRfM1upnV7zxKhCU+8LtI= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=columbia.edu header.s=pps01 header.b=pBQ67VJ4; spf=pass (imf23.hostedemail.com: domain of tz2294@columbia.edu designates 148.163.139.74 as permitted sender) smtp.mailfrom=tz2294@columbia.edu; dmarc=pass (policy=none) header.from=columbia.edu ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1775158383; a=rsa-sha256; cv=none; b=r9xkmEwWvPDpzkk1ADaAxGW8QcqhiR+7EPrLNARTiXUmZbWu3h8C3uzxQm6V9aLapAr8Zd B1uMkUrZIah8uOZU4KMU5iJzo3BDGHyV5SaOilSMXgJuj8t6xj2jdLYuA5l3+GXD3qNUDW eOA5TfGIUKQ9O5GIkkhfZJKNhDEXKcI= Received: from pps.filterd (m0167075.ppops.net [127.0.0.1]) by mx0b-00364e01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 632JSl3M408330 for ; Thu, 2 Apr 2026 15:33:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=columbia.edu; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=pps01; bh=1Wma Gc9Te9yz0Zibs0J92PxP2axqg3Ucqwb44WM0s3g=; b=pBQ67VJ46+SO5CMoxNw4 10vf2BWyi8pCFVjd3/INcGVNa2Rx4KtH2rep92OIs2n1Z89uB2lTfNviu+kbwbPd DjAPZzTjPlQJxf6aaLj8+55swS1/gYcctqfhFYgYzhKlR/0crQjLSGCN03sDQss9 4tZHP4P+wILE7QdbAjcgpe5P/Ff4my0GTEA5qtpp8D85WKZQFROup1Kp2l2MpjiS 9Yj3nNMZauc2U5s34Um9d9jiL/3yeihYWBvWrqrsZRhGbHQbSjGDG8Q5TIp8ZYZM cU3Bx2XRUUejxzakioCYxP6G9EC5W5f3QZfaBWft5Fh55KmbHTKoFuO3cCmIUNz2 vA== Received: from mail-qk1-f198.google.com (mail-qk1-f198.google.com [209.85.222.198]) by mx0b-00364e01.pphosted.com (PPS) with ESMTPS id 4d96kcsx4g-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Thu, 02 Apr 2026 15:33:01 -0400 (EDT) Received: by mail-qk1-f198.google.com with SMTP id af79cd13be357-8d3bea3aa34so117575585a.0 for ; Thu, 02 Apr 2026 12:33:01 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1775158381; x=1775763181; h=content-transfer-encoding:in-reply-to:from:content-language :references:cc:to:subject:user-agent:mime-version:date:message-id :x-gm-gg:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=1WmaGc9Te9yz0Zibs0J92PxP2axqg3Ucqwb44WM0s3g=; b=g5uCYG87Cs+Q42ZbTy4+ZrvslC1MFrslI73FEZGdduUpPexvAOa9bS9f8uQWxX+TJy AD7gic6xi900IkZTrWnL6et50O5fpd46mIjMfQj8AHlAAjgzf1dIEUYFVf6b+BJjN2wp df7yrXHA9WAZRVkOp36oDpM4Eik9TN6Zdlxjyzpwwjk+anRsd3gmfx6QZkj/tyfDTNX7 Tvj847me/23apGZ3s02FlyetGC2pzx2UBdzLZnsxlG9oeaB/l5WTQbRg2SfJ3ZHkrbrE Rytlpuq1p0ab5sC+ctgchCDraZRIhvwJYFoKw51Rs3YNm7ESmdGgPD8N2MwKS6C3G0r6 8vJg== X-Forwarded-Encrypted: i=1; AJvYcCWEyTyKF/rD/G8tHX/DlNlloD5xYvtbHUbBT/JnIK+DQm63F+SZGC3TRlHCwHwvkqDrYxZhPakhtw==@kvack.org X-Gm-Message-State: AOJu0YwBCKg9RsP9HIr/OlDA8nmZsX7SWDbcBBNKv7DbdH5emHhefVB5 pkfhmi+P6E3gJNkrkJktmpCIf0NzyUUxuw5wDeC7edheO6lFXTUH2klMhEmpyhXth8ocPffjxhM 7Aog9428G5AlejK4Tr0/PpMgTwe7W+wYoWzjBjKNrrHeSOdNN X-Gm-Gg: ATEYQzxPp5vOBMv2XkrUxY60TAy1HRHFKCjaBCyvAz7GfqqHPkExDnUsqGfbL+3Yt45 p2hjqrXsNoHsxwzUCXAnEiUgMhI1TPkt2F14Sy4EGabZg/lOrojDJoHBoDxejJW8kEYD6lSOMVY HGA+BXSOE7qG/D2drQYgnojgijLsYWWjqv2y6sl24Lf630mAfuSQuJ1u16xn+Z5TTokE/5qQBff lMvxoLAfT6o7FBVfkOJumfwuPVUeOEh7XCEj/Ndj2r1wzPx55HO2tQmx2IwGjBTOC4ZM5H6Fiuu RvOEOs6MG3qzyywX7Pc7YkiNcrA265HYwJ+huGIFtmSAbjVz3Y91Poo+BaWTPwBddsCTQaXhxK8 H35DZ4UADkLlnAxEH+zEO3ClU9o41KTAhy1WQ0mg= X-Received: by 2002:a05:620a:298b:b0:8cd:9599:b7cb with SMTP id af79cd13be357-8d41c6ac558mr84740285a.25.1775158380997; Thu, 02 Apr 2026 12:33:00 -0700 (PDT) X-Received: by 2002:a05:620a:298b:b0:8cd:9599:b7cb with SMTP id af79cd13be357-8d41c6ac558mr84732685a.25.1775158380358; Thu, 02 Apr 2026 12:33:00 -0700 (PDT) Received: from [10.206.121.101] ([129.236.224.148]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8d2a80680dcsm283333085a.26.2026.04.02.12.32.58 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 02 Apr 2026 12:32:59 -0700 (PDT) Message-ID: <6a171abc-ebd2-4ddf-8c36-34c66ca42043@columbia.edu> Date: Thu, 2 Apr 2026 15:32:58 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 07/15] userfaultfd: introduce vm_uffd_ops To: Mike Rapoport , Andrew Morton , David Hildenbrand Cc: Andrea Arcangeli , Andrei Vagin , Axel Rasmussen , Baolin Wang , Harry Yoo , Hugh Dickins , James Houghton , "Liam R. Howlett" , "Lorenzo Stoakes (Oracle)" , "Matthew Wilcox (Oracle)" , Michal Hocko , Muchun Song , Nikita Kalyazin , Oscar Salvador , Paolo Bonzini , Peter Xu , Sean Christopherson , Shuah Khan , Suren Baghdasaryan , Vlastimil Babka , kvm@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-mm@kvack.org References: <20260402041156.1377214-1-rppt@kernel.org> <20260402041156.1377214-8-rppt@kernel.org> Content-Language: en-US From: Tal Zussman In-Reply-To: <20260402041156.1377214-8-rppt@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Proofpoint-GUID: cml9qAjYYpqxPTxVJIh2eFRuBUJOHPpr X-Authority-Analysis: v=2.4 cv=bMMb4f+Z c=1 sm=1 tr=0 ts=69cec46d cx=c_pps a=qKBjSQ1v91RyAK45QCPf5w==:117 a=k+Kg2sH3hDje3YXt6xVjPQ==:17 a=IkcTkHD0fZMA:10 a=A5OVakUREuEA:10 a=x7bEGLp0ZPQA:10 a=VkNPw1HP01LnGYTKEx00:22 a=Da8U98TiO7q1upZEImrf:22 a=HpS3TJQ9O3Ob1ozEcmik:22 a=VwQbUJbxAAAA:8 a=20KFwNOVAAAA:8 a=-OANyN2A5GHSoQQpHzcA:9 a=QEXdDO2ut3YA:10 a=NFOGd7dJGGMPyQGDc5-O:22 X-Proofpoint-ORIG-GUID: cml9qAjYYpqxPTxVJIh2eFRuBUJOHPpr X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNDAyMDE3NSBTYWx0ZWRfX+XuqwWOOLwZ9 13ZmON8+K388uVHD/k1t9SQ+eVPAQ4b2FS5vQosMBVCzAJ8dOP7V3H1PXpDNOPLFU7KzcNf99P+ iipttJyCZGsK+luYOepiAnxW74raPQGNJ+hOytwaz+zT/oCQERhxGJTBOPL5Qc9QAjQYOxcTHNt qUcg74YBPku6ZCXbU2Hnt2DhGOFBxqYjZwECPylHZg3YHmbKMfoGWRsMJBJBr5gaYjNf8JnX49Q YMazuxVHczxGhZVMA5tSuNLpSw0B06iIyvfV47gjUpn18GRnui81iGKRWEoDUj+HlO2+DawfqHY dXWkkIL96O7JpyPIdpqiCtP5Rxcgx2aj/B8r7s/KSvxX1mFWBe1rhMxVRxkNxgpPV5+j0XyF1F+ Zzfn69QMgcNK6YJ/j/gz11WwSOvsJCnZmGMzMbpL5zwxIqIKfduJnaFBVkMCQBFK/h9GylvP7ld woletlGAyb7xIDQR0LQ== X-Proofpoint-Virus-Version: vendor=nai engine=6800 definitions=11747 signatures=596818 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 malwarescore=0 lowpriorityscore=10 suspectscore=0 clxscore=1015 spamscore=0 impostorscore=10 adultscore=0 bulkscore=10 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2603050001 definitions=main-2604020175 X-Rspamd-Queue-Id: 33326140012 X-Stat-Signature: g41ajiihcpcchydod1qaygn1npmuej36 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1775158383-790181 X-HE-Meta: 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 H9fdhSW1 H5i8QLbBBlACWl+1Obleovl0Ha615s7BLm4qDlmKlZes5AHlTRKhvkV+wUnZ9wi6ncGLYH+lZVVLqng9WOGAZcacoLilBwE7AKr8MjFkvyuZaC+B0rxXVasyIdiV8PUKgO/irNdp+SkZ1LTSfkjkeigke1ItiuKQZTNAIL4jf8xeR/L3BrnR7yE7/YCbT1kn5gLwSQ8Wxw35OxgPZO05vhwmAD3lxpSOR/YUREn5r4Q2Z054BIRfHSLl8M3ianXzMaAaQf9Gw/HtqYzjWJazfwK/tVvXH03sLGVly1OJBTC9FGQtUM49I6At1kqAqvwNxCw5g+KOfmYv5ZtLerfEIDCOIuznOoH/cg2V7gD2jxJdjreWxkr+ZZ1ypWfvZ9r5FNqZmiEE8MNGZkYtla6It92TuI5HWU2pYTB9HN5APzO+vlY0/9rnsLgq1kaLYKfSjly+Ec5U34/ZJETc3c8DD9GaNbLgey0fPNqZFT1iKqgoMWP1Nk3PFaSMox2qsXKYd2C2qUbjuVHVsbUgW8LNDmI9Ui+/OExydTbiuTlD1o8BbtFGyHw9/o6mv4lVmFfsa1W+/ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Mike, On 4/2/26 12:11 AM, Mike Rapoport wrote: > @@ -2021,34 +2040,33 @@ ssize_t move_pages(struct userfaultfd_ctx *ctx, unsigned long dst_start, > bool vma_can_userfault(struct vm_area_struct *vma, vm_flags_t vm_flags, > bool wp_async) > { > - vm_flags &= __VM_UFFD_FLAGS; > + const struct vm_uffd_ops *ops = vma_uffd_ops(vma); > > - if (vma->vm_flags & VM_DROPPABLE) > - return false; > - > - if ((vm_flags & VM_UFFD_MINOR) && > - (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma))) > - return false; > + vm_flags &= __VM_UFFD_FLAGS; > > /* > - * If wp async enabled, and WP is the only mode enabled, allow any > + * If WP is the only mode enabled and context is wp async, allow any > * memory type. > */ > if (wp_async && (vm_flags == VM_UFFD_WP)) > return true; > > + /* For any other mode reject VMAs that don't implement vm_uffd_ops */ > + if (!ops) > + return false; > + > + if (vma->vm_flags & VM_DROPPABLE) > + return false; > + Doesn't moving the VM_DROPPABLE check after the wp_async early return make the issue David raised in [1] possible again (i.e. moving swapbacked pages into a droppable region using UFFDIO_MOVE)? With this change, VM_DROPPABLE pages can now be registered with uffd under wp_async, which allows UFFDIO_MOVE. I think the VM_DROPPABLE check should go right before the wp_async check. And it would probably benefit from a comment... [1] https://lore.kernel.org/linux-mm/5a875a3a-2243-4eab-856f-bc53ccfec3ea@redhat.com/ Thanks, Tal