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 330F5C4321E for ; Tue, 29 Nov 2022 14:05:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C91A96B0071; Tue, 29 Nov 2022 09:05:09 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id C42046B0074; Tue, 29 Nov 2022 09:05:09 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AE2B26B0075; Tue, 29 Nov 2022 09:05:09 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 9EC566B0071 for ; Tue, 29 Nov 2022 09:05:09 -0500 (EST) Received: from smtpin13.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 3F925140FF4 for ; Tue, 29 Nov 2022 14:05:09 +0000 (UTC) X-FDA: 80186651538.13.E72AB70 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by imf21.hostedemail.com (Postfix) with ESMTP id A44631C0033 for ; Tue, 29 Nov 2022 14:05:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1669730705; x=1701266705; h=date:from:to:cc:subject:message-id:reply-to:references: mime-version:in-reply-to; bh=CqOGW8Zm184KDMv0CHU80C03eQzUbVrHdpSNa5YjJCg=; b=bKgSegQWEm/FLuZ5PvxIhiU0vHMcUlFxjmmFzGpgetLP0u/Eb4ZieUls aj8VSmnZnUJOQF2WUYSPEAuyzxUpryHYqcLQEfiENcevBMS2sDfGCqwrl xu4dKVHQh6a7MyVhg/mfqmqgK0WgrShp+4tAF+fI6YrtovA3KaXV18JT3 MBeISIWVr5ruxJ2Lpj9Tsz64SrgH+nPVVXtpBHbWzEEkeHmRRpygic+59 E6JwHU4ERiWhVJInfqed2WdFAxlnh4sARtsPfQsIwTWsieA8O9Ai/GJez 1NV1QOQctoWa9YxEie9L07SOM+6bk9h3HaAMj0lgpWOsP0URPE0WJBLkZ w==; X-IronPort-AV: E=McAfee;i="6500,9779,10546"; a="316948592" X-IronPort-AV: E=Sophos;i="5.96,203,1665471600"; d="scan'208";a="316948592" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Nov 2022 06:04:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10546"; a="707221830" X-IronPort-AV: E=Sophos;i="5.96,203,1665471600"; d="scan'208";a="707221830" Received: from chaop.bj.intel.com (HELO localhost) ([10.240.193.75]) by fmsmga008.fm.intel.com with ESMTP; 29 Nov 2022 06:04:07 -0800 Date: Tue, 29 Nov 2022 21:59:46 +0800 From: Chao Peng To: David Hildenbrand Cc: "Kirill A. Shutemov" , Michael Roth , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, linux-doc@vger.kernel.org, qemu-devel@nongnu.org, Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H . Peter Anvin" , Hugh Dickins , Jeff Layton , "J . Bruce Fields" , Andrew Morton , Shuah Khan , Mike Rapoport , Steven Price , "Maciej S . Szmigiero" , Vlastimil Babka , Vishal Annapurve , Yu Zhang , "Kirill A . Shutemov" , luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com, ak@linux.intel.com, aarcange@redhat.com, ddutile@redhat.com, dhildenb@redhat.com, Quentin Perret , tabba@google.com, mhocko@suse.com, Muchun Song , wei.w.wang@intel.com Subject: Re: [PATCH v9 1/8] mm: Introduce memfd_restricted system call to create restricted user memory Message-ID: <20221129135946.GB902164@chaop.bj.intel.com> Reply-To: Chao Peng References: <20221025151344.3784230-1-chao.p.peng@linux.intel.com> <20221025151344.3784230-2-chao.p.peng@linux.intel.com> <20221129000632.sz6pobh6p7teouiu@amd.com> <20221129112139.usp6dqhbih47qpjl@box.shutemov.name> <6d7f7775-5703-c27a-e57b-03aafb4de712@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6d7f7775-5703-c27a-e57b-03aafb4de712@redhat.com> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669730707; a=rsa-sha256; cv=none; b=lox4rRWqJse8Qi6qGPick+3p7kzsRT+Bh43cvkDvBSFJ6Eg9TQrJU/k3df+3duS8S3bV32 eKsdGR1NKR6Nr4capPIlxJ/4tj3V5k8LlI3LtOtO8nAYMSxrzXw1oSmqZgylH07contzFt TuEwOmk9wZbDznfPUT02Do+/IF2o2Sw= ARC-Authentication-Results: i=1; imf21.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=bKgSegQW; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf21.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=chao.p.peng@linux.intel.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1669730707; h=from:from:sender:reply-to: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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=KaNU/krBgWxEr3k0gnptPtiop5weq7clESL9aE86rys=; b=fVvz2tBFBT9XhwR7ApkyyTj8ntuoIFPLvLDVjXK7zW/3F4Wy/wBFdlM9eFEhmg7pO+Nzxi KngV7UqLC3r/G96/7RvsnqBPbNJW5fDcp3pSCvpbj+wa2HA6dD8IDc/xkkeIyry1VYgOtt Ot46a631MVXWZadUB9+oLHpOm1jxj/E= X-Rspamd-Queue-Id: A44631C0033 Authentication-Results: imf21.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=bKgSegQW; dmarc=fail reason="No valid SPF" header.from=intel.com (policy=none); spf=none (imf21.hostedemail.com: domain of chao.p.peng@linux.intel.com has no SPF policy when checking 134.134.136.65) smtp.mailfrom=chao.p.peng@linux.intel.com X-Rspamd-Server: rspam12 X-Rspam-User: X-Stat-Signature: pezb46qy5gkn11weu5e7691paax3t8hg X-HE-Tag: 1669730705-441736 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: On Tue, Nov 29, 2022 at 12:39:06PM +0100, David Hildenbrand wrote: > On 29.11.22 12:21, Kirill A. Shutemov wrote: > > On Mon, Nov 28, 2022 at 06:06:32PM -0600, Michael Roth wrote: > > > On Tue, Oct 25, 2022 at 11:13:37PM +0800, Chao Peng wrote: > > > > From: "Kirill A. Shutemov" > > > > > > > > > > > > > > > > > +static struct file *restrictedmem_file_create(struct file *memfd) > > > > +{ > > > > + struct restrictedmem_data *data; > > > > + struct address_space *mapping; > > > > + struct inode *inode; > > > > + struct file *file; > > > > + > > > > + data = kzalloc(sizeof(*data), GFP_KERNEL); > > > > + if (!data) > > > > + return ERR_PTR(-ENOMEM); > > > > + > > > > + data->memfd = memfd; > > > > + mutex_init(&data->lock); > > > > + INIT_LIST_HEAD(&data->notifiers); > > > > + > > > > + inode = alloc_anon_inode(restrictedmem_mnt->mnt_sb); > > > > + if (IS_ERR(inode)) { > > > > + kfree(data); > > > > + return ERR_CAST(inode); > > > > + } > > > > + > > > > + inode->i_mode |= S_IFREG; > > > > + inode->i_op = &restrictedmem_iops; > > > > + inode->i_mapping->private_data = data; > > > > + > > > > + file = alloc_file_pseudo(inode, restrictedmem_mnt, > > > > + "restrictedmem", O_RDWR, > > > > + &restrictedmem_fops); > > > > + if (IS_ERR(file)) { > > > > + iput(inode); > > > > + kfree(data); > > > > + return ERR_CAST(file); > > > > + } > > > > + > > > > + file->f_flags |= O_LARGEFILE; > > > > + > > > > + mapping = memfd->f_mapping; > > > > + mapping_set_unevictable(mapping); > > > > + mapping_set_gfp_mask(mapping, > > > > + mapping_gfp_mask(mapping) & ~__GFP_MOVABLE); > > > > > > Is this supposed to prevent migration of pages being used for > > > restrictedmem/shmem backend? > > > > Yes, my bad. I expected it to prevent migration, but it is not true. > > Maybe add a comment that these pages are not movable and we don't want to > place them into movable pageblocks (including CMA and ZONE_MOVABLE). That's > the primary purpose of the GFP mask here. Yes I can do that. Chao > > -- > Thanks, > > David / dhildenb