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=-6.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,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 F361BC433E9 for ; Mon, 25 Jan 2021 21:55:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CD89F216FD for ; Mon, 25 Jan 2021 21:55:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733007AbhAYVsz (ORCPT ); Mon, 25 Jan 2021 16:48:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:36284 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732834AbhAYVib (ORCPT ); Mon, 25 Jan 2021 16:38:31 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5F8A2229C6; Mon, 25 Jan 2021 21:35:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1611610543; bh=2Di0IbIXl1xn2Q918lq0pHS35BBSv9IAQLWTpnF3034=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Cy17SSKvvNvxfTqzme3GulWvb12hmNhkF7DBhyy2a+M5IaoGf8exm+dMOhwdI3cnD O9Y6le+GeozBAOlFWKkpEB+vZ71maF7XrODlor4nn34mqAaY2SmcJJTy1/7R4Vzp0U bPshjl150D1+6AqGJJwRZluiwgpDdWOErZGjlhYbAQhuHLMYpqQxkt2okbl3QmaaEV +AvTUTAKQGnim5uoCQhk9nL/vcRX66pRqMexDaS2sIjDuNGgW078c+2BX0w5Eu0hmE oc6a5eiysTeaoVlQWOTzqTt5FOVdCY/F5kyVzE2NWYn7vW0p6El384BwmC/nQzLCGf IjSwSAhpZJ+aA== Date: Mon, 25 Jan 2021 23:35:26 +0200 From: Mike Rapoport To: Shakeel Butt Cc: Matthew Wilcox , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , David Hildenbrand , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , 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 , Linux MM , LKML , 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 08/11] secretmem: add memcg accounting Message-ID: <20210125213526.GK6332@kernel.org> References: <20210121122723.3446-1-rppt@kernel.org> <20210121122723.3446-9-rppt@kernel.org> <20210125161706.GE308988@casper.infradead.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 Mon, Jan 25, 2021 at 09:18:04AM -0800, Shakeel Butt wrote: > On Mon, Jan 25, 2021 at 8:20 AM Matthew Wilcox wrote: > > > > On Thu, Jan 21, 2021 at 02:27:20PM +0200, Mike Rapoport wrote: > > > From: Mike Rapoport > > > > > > Account memory consumed by secretmem to memcg. The accounting is updated > > > when the memory is actually allocated and freed. I though about doing per-page accounting, but then one would be able to create a lot of secretmem file descriptors, use only a page from each while actual memory consumption will be way higher. > > I think this is wrong. It fails to account subsequent allocators from > > the same PMD. If you want to track like this, you need separate pools > > per memcg. > > > > Are these secretmem pools shared between different jobs/memcgs? A secretmem pool is per anonymous file descriptor and this file descriptor can be shared only explicitly between several processes. So, the secretmem pool should not be shared between different jobs/memcg. Of course, it's possible to spread threads of a process across different memcgs, but in that case the accounting will be similar to what's happening today with sl*b. The first thread to cause kmalloc() will be charged for the allocation of the entire slab and subsequent allocations from that slab will not be accounted. That said, having a pool per memcg will add ton of complexity with very dubious value. -- Sincerely yours, Mike.