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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AE6F8C4332F for ; Fri, 8 Oct 2021 14:57:41 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3C90460FC1 for ; Fri, 8 Oct 2021 14:57:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3C90460FC1 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id A091B6B0071; Fri, 8 Oct 2021 10:57:40 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 99255900002; Fri, 8 Oct 2021 10:57:40 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 80B1D6B0073; Fri, 8 Oct 2021 10:57:40 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0210.hostedemail.com [216.40.44.210]) by kanga.kvack.org (Postfix) with ESMTP id 6EB976B0071 for ; Fri, 8 Oct 2021 10:57:40 -0400 (EDT) Received: from smtpin39.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 211613A2B2 for ; Fri, 8 Oct 2021 14:57:40 +0000 (UTC) X-FDA: 78673574280.39.64EB114 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by imf12.hostedemail.com (Postfix) with ESMTP id C31DB1000A9F for ; Fri, 8 Oct 2021 14:57:39 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out2.suse.de (Postfix) with ESMTP id A6D9A1FF47; Fri, 8 Oct 2021 14:57:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1633705058; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=hLBV1SjSGEf+OI0gMp4JXsVXBC5E4MDos4xMm1nlyIE=; b=V9a1bNcXmSTGtAC+pLehQf0TNb+WqUBKqvPBGNoYRau2lx3dBFc9cpVz2iuJwOf3CZ68lo m1Kp83OfKs1MNfHLP+SzZYlja2GZA+yytMpzsczDHl48CJP2Lx4PSLmDqHIYE70JMUhp+8 6IOMzE1R+T9mYzGuYqqPfhwj18k06Lg= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 084BFA3B89; Fri, 8 Oct 2021 14:57:36 +0000 (UTC) Date: Fri, 8 Oct 2021 16:57:32 +0200 From: Michal Hocko To: Dave Hansen Cc: Kees Cook , Suren Baghdasaryan , Pavel Machek , Rasmus Villemoes , David Hildenbrand , John Hubbard , Andrew Morton , Colin Cross , Sumit Semwal , Matthew Wilcox , "Kirill A . Shutemov" , Vlastimil Babka , Johannes Weiner , Jonathan Corbet , Al Viro , Randy Dunlap , Kalesh Singh , Peter Xu , rppt@kernel.org, Peter Zijlstra , Catalin Marinas , vincenzo.frascino@arm.com, Chinwen Chang =?utf-8?B?KOW8temMpuaWhyk=?= , Axel Rasmussen , Andrea Arcangeli , Jann Horn , apopple@nvidia.com, Yu Zhao , Will Deacon , fenghua.yu@intel.com, thunder.leizhen@huawei.com, Hugh Dickins , feng.tang@intel.com, Jason Gunthorpe , Roman Gushchin , Thomas Gleixner , krisman@collabora.com, Chris Hyser , Peter Collingbourne , "Eric W. Biederman" , Jens Axboe , legion@kernel.org, Rolf Eike Beer , Cyrill Gorcunov , Muchun Song , Viresh Kumar , Thomas Cedeno , sashal@kernel.org, cxfcosmos@gmail.com, LKML , linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm , kernel-team Subject: Re: [PATCH v10 3/3] mm: add anonymous vma name refcounting Message-ID: References: <92cbfe3b-f3d1-a8e1-7eb9-bab735e782f6@rasmusvillemoes.dk> <20211007101527.GA26288@duo.ucw.cz> <202110071111.DF87B4EE3@keescook> <4a1dd04f-eda3-5c71-4772-726fd6fa2a38@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4a1dd04f-eda3-5c71-4772-726fd6fa2a38@intel.com> Authentication-Results: imf12.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=V9a1bNcX; spf=pass (imf12.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.29 as permitted sender) smtp.mailfrom=mhocko@suse.com; dmarc=pass (policy=quarantine) header.from=suse.com X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: C31DB1000A9F X-Stat-Signature: 595a3rdhshg69fx6z73xhrmrybtzycr5 X-HE-Tag: 1633705059-855223 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 08-10-21 07:14:58, Dave Hansen wrote: > On 10/7/21 11:34 PM, Michal Hocko wrote: > >> Yes, please. It really seems like the folks that are interested in this > >> feature want strings. (I certainly do.) > > I am sorry but there were no strong arguments mentioned for strings so > > far. > > The folks who want this have maintained an out-of-tree patch using > strings. They've maintained it for the better part of a decade. I > don't know how widely this shipped in the Android ecosystem, but I > suspect we're talking about billions of devices. Right? > > This is a feature that, if accepted into mainline, will get enabled and > used on billions of devices. If we dumb this down to integers, it's not > 100% clear that it _will_ get used. > > That's a pretty strong argument in my book, even if the contributors > have difficulty articulating exactly why they want strings. I would agree that if integers would make this unusable then this would be a strong argument. But I haven't really heard any arguments like that so far. I have heard about IPC overhead and other speculations that do not seem really convincing. We shouldn't hand wave concerns regarding the implementation complexity and resource handling just by "somebody has been using this for decates", right? Do not get me wrong. This is going to become a user interface and we will have to maintain it for ever. As such an extra scrutiny has to be applied. -- Michal Hocko SUSE Labs