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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 F20BAC433E6 for ; Fri, 29 Jan 2021 07:54:06 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 5DF6E64E00 for ; Fri, 29 Jan 2021 07:54:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5DF6E64E00 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 646BB6B0005; Fri, 29 Jan 2021 02:54:03 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5CEA16B0006; Fri, 29 Jan 2021 02:54:03 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 4975B6B0071; Fri, 29 Jan 2021 02:54:03 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0058.hostedemail.com [216.40.44.58]) by kanga.kvack.org (Postfix) with ESMTP id 2FCF76B0005 for ; Fri, 29 Jan 2021 02:54:03 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id E8B3E181AEF21 for ; Fri, 29 Jan 2021 07:54:02 +0000 (UTC) X-FDA: 77758049124.19.fuel22_5e01fa6275a6 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin19.hostedemail.com (Postfix) with ESMTP id C632F1AD31E for ; Fri, 29 Jan 2021 07:54:02 +0000 (UTC) X-HE-Tag: fuel22_5e01fa6275a6 X-Filterd-Recvd-Size: 4100 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf32.hostedemail.com (Postfix) with ESMTP for ; Fri, 29 Jan 2021 07:54:02 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1611906841; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=Qq/LTzApf3bN0KeQhA5voHbd39mSTuwpVJHWgFqS7tI=; b=VeS+erlQ/D0mICcn4h1apyKupa7vysv7jPuADT7gGBStXgvb2Mh94pxpNtxq3ZHFM6eVx2 AzZTdG6HodXjhRfYzr8XnVmsRMMpIlEG/g/WmygtSF5VOOokvXwPyg8PvtC3BvdtYDoTuK +Ynl/lAwL00OK4XFtLs9b+94Viv/g4c= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AFFA7AC55; Fri, 29 Jan 2021 07:54:00 +0000 (UTC) Date: Fri, 29 Jan 2021 08:53:59 +0100 From: Michal Hocko To: James Bottomley Cc: Mike Rapoport , 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: References: <20210121122723.3446-1-rppt@kernel.org> <20210121122723.3446-8-rppt@kernel.org> <20210126114657.GL827@dhcp22.suse.cz> <303f348d-e494-e386-d1f5-14505b5da254@redhat.com> <20210126120823.GM827@dhcp22.suse.cz> <20210128092259.GB242749@kernel.org> <73738cda43236b5ac2714e228af362b67a712f5d.camel@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <73738cda43236b5ac2714e228af362b67a712f5d.camel@linux.ibm.com> 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 Thu 28-01-21 13:05:02, James Bottomley wrote: > On Thu, 2021-01-28 at 14:01 +0100, Michal Hocko wrote: [...] > > I am also still not sure why this whole thing is not just a > > ramdisk/ramfs which happens to unmap its pages from the direct > > map. Wouldn't that be a much more easier model to work with? You > > would get an access control for free as well. > > The original API was a memfd which does have this access control as > well. However, the decision was made after much discussion to go with > a new system call instead. It would be really great to summarize reasoning behind that decision. Not only for those who were not part of those discussion but also for anybody who will be reading git log and want to try to understand that reasoning. Go and read 15 versions of patchset to find that out is certainly not great use of time. Thanks! -- Michal Hocko SUSE Labs