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 B9391C433E6 for ; Thu, 4 Feb 2021 10:00:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64B9164F55 for ; Thu, 4 Feb 2021 10:00:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235285AbhBDJ7z (ORCPT ); Thu, 4 Feb 2021 04:59:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:45044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232838AbhBDJ7x (ORCPT ); Thu, 4 Feb 2021 04:59:53 -0500 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: Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org 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. 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=-3.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 71BDBC433E0 for ; Thu, 4 Feb 2021 09:59:16 +0000 (UTC) Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id F20BA64F59 for ; Thu, 4 Feb 2021 09:59:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F20BA64F59 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org Received: from ml01.vlan13.01.org (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 93035100EB33C; Thu, 4 Feb 2021 01:59:15 -0800 (PST) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=198.145.29.99; helo=mail.kernel.org; envelope-from=rppt@kernel.org; receiver= Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 39E88100EC1C8 for ; Thu, 4 Feb 2021 01:59:13 -0800 (PST) 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 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-Disposition: inline In-Reply-To: Message-ID-Hash: RMUJARZ7Y7IXAL2YO7LSL65522SK2MOL X-Message-ID-Hash: RMUJARZ7Y7IXAL2YO7LSL65522SK2MOL X-MailFrom: rppt@kernel.org X-Mailman-Rule-Hits: nonmember-moderation X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation CC: James Bottomley , David Hildenbrand , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , 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 X-Mailman-Version: 3.1.1 Precedence: list List-Id: "Linux-nvdimm developer list." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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. _______________________________________________ Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org To unsubscribe send an email to linux-nvdimm-leave@lists.01.org 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=-4.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 3EE93C433E0 for ; Thu, 4 Feb 2021 09:59:30 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BD1EC64DDB for ; Thu, 4 Feb 2021 09:59:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD1EC64DDB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=hZ5BKFWIwQ50inOhKWrwoZgspTPv0MS152ar2N4vmlQ=; b=dQKeHhfluE+CNNS1Gk4WvEYsw cNc6AHTjQlwPIAZ4oOU/CfT31hhQWo1rKibrIr2PZD0vCoc3l6LjCWbO/e5C+5SuHOIZTRn8fh7PD RPWbKWfI9ZR1odq0w64TFOUfMdhWg6sM2Li9aIGhjBO/HfNiPswpvx/txOYNEyglni8t2AQh7RLTC EHZMG9tiPCRIsBGAb6x5A+OUYl2ME+PvytOn1GNEHLt1qgWiEjIuH2MKbOghkx7LFpCrnYGzavAP6 JoTYul1PFkhuFqBiJn+owvi0pVdpBgHGXUNt4OozoL+NCJVJnpijWU4elKyWuYJnpRx6m3M5d1Hin wl3KdmlVw==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7bQ0-0003Iu-Lu; Thu, 04 Feb 2021 09:59:20 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7bPu-0003Gp-Qh; Thu, 04 Feb 2021 09:59:15 +0000 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 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-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210204_045915_027119_46414CE4 X-CRM114-Status: GOOD ( 17.94 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , David Hildenbrand , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Palmer Dabbelt , Arnd Bergmann , James Bottomley , Hagen Paul Pfeifer , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org 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. _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv 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=-4.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 E96A1C433E0 for ; Thu, 4 Feb 2021 10:00:37 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 8CE0664DDB for ; Thu, 4 Feb 2021 10:00:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8CE0664DDB Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Fo3y7getr3g5PkHVhxszLK+vDGVrMPM1anwjBOQ/5S0=; b=liIZ5pZLzxveJ9IbCDfevn3sb QKxUoh8OkEm4fhLjdrPDncCwRikAYqP8fjV77vaNeVPDVWZrYZ0fldHOMxaqW6N1kS4Q6eyPc9iRo qgUSAGUFVyGMGO9kIJVSUID4p4Tq6WWfecWMn5FGRqnZx92ILeQmPlhhajZqM2FSzCGmmZMF+A/dH KkBIVRsnHKbcZS28FlkTNlyrwPe76FRMpwiSBDA931kzTiiwrlXaa9y0osNQwY/mxeyldGNQSq/ec xzEc9J1akuR8RSMqryKCpfsmDvkc8cLc3htb1/ZPtflyrPlN7pZek8MMXzF+wbY8tUVaoSjVI0UUg LMXlV6Xxg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7bPy-0003IK-4W; Thu, 04 Feb 2021 09:59:18 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1l7bPu-0003Gp-Qh; Thu, 04 Feb 2021 09:59:15 +0000 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 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-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210204_045915_027119_46414CE4 X-CRM114-Status: GOOD ( 17.94 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , David Hildenbrand , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Palmer Dabbelt , Arnd Bergmann , James Bottomley , Hagen Paul Pfeifer , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel