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=-1.1 required=3.0 tests=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 8B5F1C33CB6 for ; Wed, 22 Jan 2020 10:42:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 629602468C for ; Wed, 22 Jan 2020 10:42:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579689755; bh=oC232aLcldtyrM3nflhhR6xMvRyBp754IDnOGVNfIYw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=AUIDm/0e1UBNh7qIm6AcRq27uLdM6sMEdNNZK2dY15D+hLc5nJk9ZaqQcTfhUy3Z9 5i3agcfC3lMQb5yWT9fpBDJvLJgr5efujQAaMg8r6S1OioEXcdRWOQ2wdxHz2srlrG KJfBNPBlXDPCMlVtPpi16rs8TxveoXyS1Vkes1Yw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729138AbgAVKme (ORCPT ); Wed, 22 Jan 2020 05:42:34 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:36706 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729037AbgAVKme (ORCPT ); Wed, 22 Jan 2020 05:42:34 -0500 Received: by mail-wm1-f65.google.com with SMTP id p17so6629107wma.1 for ; Wed, 22 Jan 2020 02:42:32 -0800 (PST) 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; bh=ZWrcztGPEdmdljU6rzvPLWUWlGRg7cvJpWEcVwcN7o8=; b=k/U0AaJwtoLhpUlr1Z8OEtZUc+8R4HZWPBFdHB69XLaajdysBt1yr2lsjL46K1EQNI DqvNLcr3MSp2aXjmGN8BFBjKuS4za22poJV8XHksTdeQyZUBAL195+qHqpJ0DG6IHO7V 3ytgFGurXlrG/NtEfHTqgE8E9Nurv9mh9Kq1XwAr7JPKBzFf65T7k28VJ3wdIP8SXX2n EZDVNLU+BqcQjaKd5FX+G1FTHeyJSqm4RR7dBvTw2wkdUcua5eWGf/C9q1xgLE3bkHbU 5lahq0mJDKHaIMS0wzvD9/1CnhPP2H7ikeABDr8J7gPyS3LfWZqU8hkYYiNlXxbI5cAH ni+A== X-Gm-Message-State: APjAAAVXnGZXGe4m1fEsfIcwwevVCLpzHiWt9ktyC/eD03EoRjRlt93W meD/hkKblgYrmNCW33/NdJU= X-Google-Smtp-Source: APXvYqwOXY4WlwXUfJ7If8qgml0d4AG62OZDyxS9ZDP0CGgPABYQ40tZm0CAz1TQujq4tDsEx0hzfw== X-Received: by 2002:a1c:4b01:: with SMTP id y1mr2205649wma.12.1579689752151; Wed, 22 Jan 2020 02:42:32 -0800 (PST) Received: from localhost (prg-ext-pat.suse.com. [213.151.95.130]) by smtp.gmail.com with ESMTPSA id b17sm56037447wrp.49.2020.01.22.02.42.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jan 2020 02:42:31 -0800 (PST) Date: Wed, 22 Jan 2020 11:42:30 +0100 From: Michal Hocko To: David Hildenbrand Cc: Dan Williams , Linux Kernel Mailing List , Linux MM , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Leonardo Bras , Nathan Lynch , Allison Randal , Nathan Fontenot , Thomas Gleixner , Stephen Rothwell , Anshuman Khandual , lantianyu1986@gmail.com, linuxppc-dev Subject: Re: [PATCH RFC v1] mm: is_mem_section_removable() overhaul Message-ID: <20200122104230.GU29276@dhcp22.suse.cz> References: <20200117145233.GB19428@dhcp22.suse.cz> <65606e2e-1cf7-de3b-10b1-33653cb41a52@redhat.com> <20200117152947.GK19428@dhcp22.suse.cz> <25a94f61-46a1-59a6-6b54-8cc6b35790d2@redhat.com> <20200120074816.GG18451@dhcp22.suse.cz> <20200121120714.GJ29276@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed 22-01-20 11:39:08, David Hildenbrand wrote: > >>> Really, the interface is flawed and should have never been merged in the > >>> first place. We cannot simply remove it altogether I am afraid so let's > >>> at least remove the bogus code and pretend that the world is a better > >>> place where everything is removable except the reality sucks... > >> > >> As I expressed already, the interface works as designed/documented and > >> has been used like that for years. > > > > It seems we do differ in the usefulness though. Using a crappy interface > > for years doesn't make it less crappy. I do realize we cannot remove the > > interface but we can remove issues with the implementation and I dare to > > say that most existing users wouldn't really notice. > > Well, at least powerpc-utils (why this interface was introduced) will > notice a) performance wise and b) because more logging output will be > generated (obviously non-offlineable blocks will be tried to offline). I would really appreciate some specific example for a real usecase. I am not familiar with powerpc-utils worklflows myself. -- Michal Hocko SUSE Labs