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 X-Spam-Level: X-Spam-Status: No, score=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 86121C433E6 for ; Thu, 4 Feb 2021 09:59:16 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C908464F4A for ; Thu, 4 Feb 2021 09:59:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C908464F4A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0C8836B006E; Thu, 4 Feb 2021 04:59:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 078546B0070; Thu, 4 Feb 2021 04:59:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id EA8676B0071; Thu, 4 Feb 2021 04:59:14 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0027.hostedemail.com [216.40.44.27]) by kanga.kvack.org (Postfix) with ESMTP id D1F326B006E for ; Thu, 4 Feb 2021 04:59:14 -0500 (EST) Received: from smtpin21.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 8DB5BBBFF for ; Thu, 4 Feb 2021 09:59:14 +0000 (UTC) X-FDA: 77780137428.21.work09_0400306275db Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin21.hostedemail.com (Postfix) with ESMTP id 68E5118045E9E for ; Thu, 4 Feb 2021 09:59:14 +0000 (UTC) X-HE-Tag: work09_0400306275db X-Filterd-Recvd-Size: 4507 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf42.hostedemail.com (Postfix) with ESMTP for ; Thu, 4 Feb 2021 09:59:13 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id A884364F46; Thu, 4 Feb 2021 09:59:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1612432752; bh=Zelq6D4XZGDuPo70kYTJJgaDbDwK093nuyMe02isfTI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=fZFn4SNNNsHZIThixqTd5WKR7HGKRGMdU+ddKY4VdNoOwSQ9sODqK3VgxpKL2A56s 4I3o8KBCJHtLjeKmCDkWXpGpYpGakfGQfRhSVgtlpOrfdQ5QAi0R3o4gjlXj7MIvFC Ql/7xPdKgGPYgPgsAFnGZRVBP1GrMxNjIdlhLDg3vtnKQVC0uVe1NaVVXvOSxEagFl 5y6xdti/3JckXFJOMvgjQwfxD24nH4jVxSXiirTWWQrL2Wdx2stjQ2AChARA3yWjIv HiCcrNO6+HU6R5Uv0EPl7S1u0uczvREvOdVTv98bo0LM7TPjMzx3LQFogyEOGejvpC DeRySER1corJA== Date: Thu, 4 Feb 2021 11:58:55 +0200 From: Mike Rapoport To: Michal Hocko Cc: James Bottomley , David Hildenbrand , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org, Hagen Paul Pfeifer , Palmer Dabbelt Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize direct map fragmentation Message-ID: <20210204095855.GQ242749@kernel.org> References: <20210128092259.GB242749@kernel.org> <73738cda43236b5ac2714e228af362b67a712f5d.camel@linux.ibm.com> <6de6b9f9c2d28eecc494e7db6ffbedc262317e11.camel@linux.ibm.com> <20210202124857.GN242749@kernel.org> <20210202191040.GP242749@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Wed, Feb 03, 2021 at 10:12:22AM +0100, Michal Hocko wrote: > On Tue 02-02-21 21:10:40, Mike Rapoport wrote: > > > > Let me reiterate to make sure I don't misread your suggestion. > > > > If we make secretmem an opt-in feature with, e.g. kernel parameter, the > > pooling of large pages is unnecessary. In this case there is no limited > > resource we need to protect because secretmem will allocate page by page. > > Yes. > > > Since there is no limited resource, we don't need special permissions > > to access secretmem so we can move forward with a system call that creates > > a mmapable file descriptor and save the hassle of a chardev. > > Yes, I assume you implicitly assume mlock rlimit here. Yes. > Also memcg accounting should be in place. Right, without pools memcg accounting is no different from other unevictable files. > Wrt to the specific syscall, please document why existing interfaces are > not a good fit as well. It would be also great to describe interaction > with mlock itself (I assume the two to be incompatible - mlock will fail > on and mlockall will ignore it). The interaction with mlock() belongs more to the man page, but I don't mind adding this to changelog as well. -- Sincerely yours, Mike.