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 370F4C05027 for ; Mon, 6 Feb 2023 22:32:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6D6756B0071; Mon, 6 Feb 2023 17:32:51 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 686FD6B0073; Mon, 6 Feb 2023 17:32:51 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 54F2A6B0074; Mon, 6 Feb 2023 17:32:51 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 411866B0071 for ; Mon, 6 Feb 2023 17:32:51 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay03.hostedemail.com (Postfix) with ESMTP id 0EDB6A05DA for ; Mon, 6 Feb 2023 22:32:51 +0000 (UTC) X-FDA: 80438318142.19.1B87CD7 Received: from mail-ed1-f43.google.com (mail-ed1-f43.google.com [209.85.208.43]) by imf07.hostedemail.com (Postfix) with ESMTP id 4CB2A40017 for ; Mon, 6 Feb 2023 22:32:48 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="bjqC5GS/"; spf=pass (imf07.hostedemail.com: domain of yosryahmed@google.com designates 209.85.208.43 as permitted sender) smtp.mailfrom=yosryahmed@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1675722769; h=from:from:sender: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=l7GqiDnnbtUw28nuIsiTOre+ZKz+TpI1lg7hwVstG3g=; b=4yO+TkrWlPyIKNreEqEgFO6aFlBojOYGH2pv1t6q7ngcFc0V0Exq69vxT/YHdygE5Nldwq ivqP0Ni266VanOFuAH688gSycjdfPmrCianfN1Kfz3Qif3u+xApAressN0Tj6DCCJ2f9wh 3m0xWjHCoI3afSjezTVVZM62hpXYyVU= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b="bjqC5GS/"; spf=pass (imf07.hostedemail.com: domain of yosryahmed@google.com designates 209.85.208.43 as permitted sender) smtp.mailfrom=yosryahmed@google.com; dmarc=pass (policy=reject) header.from=google.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1675722769; a=rsa-sha256; cv=none; b=l7n1jd3Zz6PO9uwHxlV80gjLV+R2fUlt2thn3X09FHFbdzHVtZvQY2TLgo8wHRTab93A25 /v+qn3jhvI92wVDt5gD7sajcm0SHnLpKUj2AwhXQ1fWybyEufkgJsg+9Ee0FQk7NM1rYjk RRtR00U71hZT3PqFZkpedOqL5Pjl4/0= Received: by mail-ed1-f43.google.com with SMTP id q19so13210253edd.2 for ; Mon, 06 Feb 2023 14:32:48 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=l7GqiDnnbtUw28nuIsiTOre+ZKz+TpI1lg7hwVstG3g=; b=bjqC5GS/eZCj8Q0tz1L7nhIPi+KBAKimBOQARz+19LvOTMg3hMzlZzkrgdDEO6xqTb B7RSKAxUSBQ5hXb3vPRlno1jQ2dpZDRN9VUVLwy02Qh424sdV3GZybk3TDAEj4DZiAFE r065BaTFJy8y+uMmf9W4ObmnllL8uoPjTyH7+iMmk8bf2TKfR6eMn2wGIaxPpVi5NtVU gZCa1vJ87AX5mxbHOJNqbU44FQI7mCgPPROEJrSQq4YL4mTjbMThGyFHIA6R3bcYqfnA 1qUiLR04aRJKbuOqI21o9cr8g3s4afL6lwp8mHwwoD5Ap2cMEjB3r52ZQmSA0Q5hczb4 e77w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=l7GqiDnnbtUw28nuIsiTOre+ZKz+TpI1lg7hwVstG3g=; b=p7ifXBZ4LA6ugBXUwYDjks7X8U1mdyBrJI6GeYMB4hefWVlV0ANPEX661u2w9RQTHa F9S06MOE/1Z/KoG6NH9TQ//YGTu/ZS2b7yFUp2oKBtdeUgJwtOn/KpE7M2KjxOqf++jB t3JSL9YMJTU0uqWeWW9bVqsgU1R/t68DivJbF7mLQcuWj07iLr9G2C9j4wAunWB6npUg elBdYqYqBRZrIcZQEK1Ab+ASpeBiLJQQmofooqKsm7EtvPVD7NK2hJcF/kT9bBSJtjb8 l9avJGuMGP4ClYpa9UPkdmMzR4jcjsZ/MtXtCCESA41DoZpwz7ipGBU9RXDAvQHn8QJ0 Aqzg== X-Gm-Message-State: AO0yUKVh5R+R92O0ayrvvaQjN4VZXL1IGcskZeHL7VkbysajTt4wsgjr g8ioyjPfnArihdhimw1W0Dk4MTZjwghXYxR3aRh7QQ== X-Google-Smtp-Source: AK7set+fpQlkQiXWMD+8ZcR3RJN1nHtZejJ0HA+mjicGMdIFu+JAoEP4S27FYorBirbtxbR7/J9pRmKttPt7Z+Se9PE= X-Received: by 2002:a50:c053:0:b0:4aa:b1a9:c77c with SMTP id u19-20020a50c053000000b004aab1a9c77cmr28409edd.5.1675722767487; Mon, 06 Feb 2023 14:32:47 -0800 (PST) MIME-Version: 1.0 References: In-Reply-To: From: Yosry Ahmed Date: Mon, 6 Feb 2023 14:32:10 -0800 Message-ID: Subject: Re: [PATCH 14/19] mm: Introduce a cgroup for pinned memory To: Tejun Heo Cc: Alistair Popple , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, jgg@nvidia.com, jhubbard@nvidia.com, tjmercier@google.com, hannes@cmpxchg.org, surenb@google.com, mkoutny@suse.com, daniel@ffwll.ch, "Daniel P . Berrange" , Alex Williamson , Zefan Li , Andrew Morton Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 4CB2A40017 X-Stat-Signature: pu9wa79f49ddyrrhe7sknqjr7orrgufe X-HE-Tag: 1675722768-339674 X-HE-Meta: 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 Aui4QEOq WWxUeCxjmTi3RNadItRI9YrSgiU7wAHDj5a3qtUgM/Qgyb8Ly1qlIFXBII8dEnvkvfXHUBf/8w9q9jayCyiSKfpZnPoMSZpVaTTQqvK+f7xVlRme+notlFygt6V68Nc4w54+tCdZIDIFF+zOxQVDxiMGgAORjjfbckseXVJRXzcheQiHI3md+SSVyn/by6jeHeNzOlu+UseZMC1MPWjgIW9Ohu6lIoD++QuLPfhQ+fMWhLsCsAIqc7xc+2DCvdjYhDwKp9cWxWsyv2cAyUSLuDMDm0yEgW13LP+fQMMRCiVaodM0= 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 Mon, Feb 6, 2023 at 1:14 PM Tejun Heo wrote: > > On Mon, Feb 06, 2023 at 06:47:51PM +1100, Alistair Popple wrote: > > If too much memory in a system is pinned or locked it can lead to > > problems such as performance degradation or in the worst case > > out-of-memory errors as such memory cannot be moved or paged out. > > > > In order to prevent users without CAP_IPC_LOCK from causing these > > issues the amount of memory that can be pinned is typically limited by > > RLIMIT_MEMLOCK. However this is inflexible as limits can't be shared > > between tasks and the enforcement of these limits is inconsistent > > between in-kernel users of pinned memory such as mlock() and device > > drivers which may also pin pages with pin_user_pages(). > > > > To allow for a single limit to be set introduce a cgroup controller > > which can be used to limit the number of pages being pinned by all > > tasks in the cgroup. > > As I wrote before, I think this might fit better as a part of memcg than as > its own controller. I guess it boils down to which we want: (a) Limit the amount of memory processes in a cgroup can be pinned/locked. (b) Limit the amount of memory charged to a cgroup that can be pinned/locked. The proposal is doing (a), I suppose if this was part of memcg it would be (b), right? I am not saying it should be one or the other, I am just making sure my understanding is clear. > > Thanks. > > -- > tejun