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=-2.5 required=3.0 tests=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 0A6D4C33CA1 for ; Mon, 20 Jan 2020 07:48:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C5BCC207FD for ; Mon, 20 Jan 2020 07:48:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C5BCC207FD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 5A2626B05C6; Mon, 20 Jan 2020 02:48:20 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 5531E6B05C7; Mon, 20 Jan 2020 02:48:20 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 443676B05C8; Mon, 20 Jan 2020 02:48:20 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0165.hostedemail.com [216.40.44.165]) by kanga.kvack.org (Postfix) with ESMTP id 2D4016B05C6 for ; Mon, 20 Jan 2020 02:48:20 -0500 (EST) Received: from smtpin19.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with SMTP id D828A8248047 for ; Mon, 20 Jan 2020 07:48:19 +0000 (UTC) X-FDA: 76397234718.19.knot41_48aecdeedea5a X-HE-Tag: knot41_48aecdeedea5a X-Filterd-Recvd-Size: 4051 Received: from mail-wr1-f66.google.com (mail-wr1-f66.google.com [209.85.221.66]) by imf04.hostedemail.com (Postfix) with ESMTP for ; Mon, 20 Jan 2020 07:48:19 +0000 (UTC) Received: by mail-wr1-f66.google.com with SMTP id q6so28286523wro.9 for ; Sun, 19 Jan 2020 23:48:19 -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:user-agent; bh=zqYxlN8e9d1Xz81Z1GDVgte6q0CcV1j9cxyhLBRYIzc=; b=QpCWO5sEzNnUEJvgrBB/YTT/3yTq8A91DBQ78hy0yyyQCBRlNcHMD8ezWnTZ+5yw6k mqN8dSNOAnSe9esog91aVXRh+DtKq8lhDTbWSMv6gGcAwQbbLrVLIogHFVEILnfv4ir3 AUhNIxvPdkEtaSo69zmxgJPOjbDhnnLe665Z2qksUuvtB5Ib2nP7GDsNqpKSxJBaJUgf Wx1HFIQhSbNjlRKW5XZb/eu39n2/zYcNZ7EPBoChx8Y9OD0QMcqKwzj24FPfwS6WNVi1 0xEbtBLhO3Y3yTaaalgLeRnniwpcOC3F7QXeyzJB8wmWXqRV8L0ktWvrT70leqsK0f3g MwXA== X-Gm-Message-State: APjAAAVJ/VqGYNX5RFC9JrX+1TcbNdQtOx5YoaCK6gxLAbXczv5cC4qO RyxMG4oHbITe74B0OZCLBvU= X-Google-Smtp-Source: APXvYqz1nmDNYIQNXhicabxXmw6QCSsn8nPgAPz6zQN+UoT7JCsFPNK6ech+vI4kj8faRntichl/eA== X-Received: by 2002:adf:fe8c:: with SMTP id l12mr16459256wrr.215.1579506498444; Sun, 19 Jan 2020 23:48:18 -0800 (PST) Received: from localhost (ip-37-188-138-155.eurotel.cz. [37.188.138.155]) by smtp.gmail.com with ESMTPSA id u16sm3099104wmj.41.2020.01.19.23.48.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Jan 2020 23:48:17 -0800 (PST) Date: Mon, 20 Jan 2020 08:48:16 +0100 From: Michal Hocko To: Dan Williams Cc: David Hildenbrand , 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: <20200120074816.GG18451@dhcp22.suse.cz> References: <20200117105759.27905-1-david@redhat.com> <20200117113353.GT19428@dhcp22.suse.cz> <20200117145233.GB19428@dhcp22.suse.cz> <65606e2e-1cf7-de3b-10b1-33653cb41a52@redhat.com> <20200117152947.GK19428@dhcp22.suse.cz> <25a94f61-46a1-59a6-6b54-8cc6b35790d2@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.2 (2019-09-21) 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 Fri 17-01-20 08:57:51, Dan Williams wrote: [...] > Unless the user is willing to hold the device_hotplug_lock over the > evaluation then the result is unreliable. Do we want to hold the device_hotplug_lock from this user readable file in the first place? My book says that this just waits to become a problem. 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... -- Michal Hocko SUSE Labs