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=-4.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 8E387C433FE for ; Mon, 7 Dec 2020 07:13:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5EBEE229C6 for ; Mon, 7 Dec 2020 07:13:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725933AbgLGHNm (ORCPT ); Mon, 7 Dec 2020 02:13:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57092 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725832AbgLGHNl (ORCPT ); Mon, 7 Dec 2020 02:13:41 -0500 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 98AB9C0613D0 for ; Sun, 6 Dec 2020 23:13:01 -0800 (PST) Received: by mail-pj1-x1042.google.com with SMTP id hk16so6904128pjb.4 for ; Sun, 06 Dec 2020 23:13:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=L9PwYZvqLiGNYdXkGMEuQ3s8+SUAaqoFC/6B9W0U+88=; b=Wylzwk2CKFjIDz3zGdDX4duOBzExSiV3Dxg2t/mMS8Jxm4Xv0e/zHY2kloviF+JjO0 TvHXgM//BGUwESKpUg8JLdziESmEA/9ne/aV8lLzA4ZiL2ya29sofiKJw7F5L5W1mcf4 GMr1U/SEvq3anM4hgHAWLyUihagFxZKQ1ZN8EB1Pi2pJl4yIILQotbe8parJgQYQuW+z 7EXk6oTqOEb98E0UdZHbxVGRYwUkXjmKqhgHMPSxsyh0TqHHA+AjbZUAin73Mo/lJP92 ik77AIHfDKRBo6PDnHDIy0ncI16UoHZrlVowJyEb8BTYFtkVJYtZm7UTPo7C27HaGmmk AOkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=L9PwYZvqLiGNYdXkGMEuQ3s8+SUAaqoFC/6B9W0U+88=; b=HSorPimvpUWJFfnWMdOB4MJz2g9rc1y26dC3ESGBrNzegLAP014LJPvnRoOV6p6YL9 jirnlIb22bBKqU5wo/fE3obNm/Mm+GHXifaWba+wmzhEJRzwz7V/GF7sYsNeNSZCwi10 8DUz5yfcTJrymywMj1/s7ZZq2GMeOQX9iIvfuqMjopcI3WJvVVEQyn5PGVg7i5v+HuQj GX2NHg/h6KdMDeyRJAsBRORi6fFidnJLatSgS1KH7DHjQ/aAsjB8VvOtEDXbEyltQDMB e4XQ2Te91nNHFyIqEHarcl6Vp9VmQA1MVlBkKzXMCCxJyoJzIbn4/cUpjXhdCSlDn5i5 ZWIg== X-Gm-Message-State: AOAM532tvIz45rq60sgU6UrnKHRtXWZP6S7zREUWzr4lYNKdJ6ZZiJBp CbnNK5mY6SF+HIjRSK/hNJs= X-Google-Smtp-Source: ABdhPJwMWJy01xons9QiIwTLpste/e0PgfoUlz9uKMNLci6bkn3kH44bcdizYodqC8v0hiVWHRvlbw== X-Received: by 2002:a17:90b:e0d:: with SMTP id ge13mr15153215pjb.111.1607325181061; Sun, 06 Dec 2020 23:13:01 -0800 (PST) Received: from js1304-desktop ([114.206.198.176]) by smtp.gmail.com with ESMTPSA id g16sm11002537pfh.187.2020.12.06.23.12.55 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sun, 06 Dec 2020 23:13:00 -0800 (PST) Date: Mon, 7 Dec 2020 16:12:50 +0900 From: Joonsoo Kim To: Pavel Tatashin Cc: Jason Gunthorpe , LKML , linux-mm , Andrew Morton , Vlastimil Babka , Michal Hocko , David Hildenbrand , Oscar Salvador , Dan Williams , Sasha Levin , Tyler Hicks , mike.kravetz@oracle.com, Steven Rostedt , Ingo Molnar , Peter Zijlstra , Mel Gorman , Matthew Wilcox , David Rientjes , John Hubbard Subject: Re: [PATCH 0/6] prohibit pinning pages in ZONE_MOVABLE Message-ID: <20201207071238.GA10731@js1304-desktop> References: <20201202052330.474592-1-pasha.tatashin@soleen.com> <20201204035953.GA17056@js1304-desktop> <20201204161005.GD5487@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 04, 2020 at 12:50:56PM -0500, Pavel Tatashin wrote: > > > Yes, this indeed could be a problem for some configurations. I will > > > add your comment to the commit log of one of the patches. > > > > It sounds like there is some inherent tension here, breaking THP's > > when doing pin_user_pages() is a really nasty thing to do. DMA > > benefits greatly from THP. > > > > I know nothing about ZONE_MOVABLE, is this auto-setup or an admin > > option? If the result of this patch is standard systems can no longer > > pin > 80% of their memory I have some regression concerns.. > > ZONE_MOVABLE can be configured via kernel parameter, or when memory > nodes are onlined after hot-add; so this is something that admins > configure. ZONE_MOVABLE is designed to gurantee memory hot-plug Just note, the origin of ZONE_MOVABLE is to provide availability of huge page, especially, hugetlb page. AFAIK, not guarantee memory hot-plug. See following commit that introduces the ZONE_MOVABLE. 2a1e274 Create the ZONE_MOVABLE zone > functionality, and not availability of THP, however, I did not know > about the use case where some admins might configure ZONE_MOVABLE to The usecase is lightly mentioned in previous discussion. http://lkml.kernel.org/r/alpine.DEB.2.23.453.2011221300100.2830030@chino.kir.corp.google.com Anyway, I agree with your other arguments and this patchset. Thanks.