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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,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 0B045C4727D for ; Wed, 23 Sep 2020 07:53:34 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A73D721924 for ; Wed, 23 Sep 2020 07:53:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="er+muJI7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A73D721924 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id F23936B006E; Wed, 23 Sep 2020 03:53:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ED3BA6B0070; Wed, 23 Sep 2020 03:53:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC2026B0071; Wed, 23 Sep 2020 03:53:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0251.hostedemail.com [216.40.44.251]) by kanga.kvack.org (Postfix) with ESMTP id C368C6B006E for ; Wed, 23 Sep 2020 03:53:32 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 81F9A1EE6 for ; Wed, 23 Sep 2020 07:53:32 +0000 (UTC) X-FDA: 77293561464.30.face75_530b22327154 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin30.hostedemail.com (Postfix) with ESMTP id 529C1180B3C83 for ; Wed, 23 Sep 2020 07:53:32 +0000 (UTC) X-HE-Tag: face75_530b22327154 X-Filterd-Recvd-Size: 3274 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Wed, 23 Sep 2020 07:53:31 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1600847610; h=from:from:reply-to:subject:subject: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=CuHUMp2i3TRP7V8scoazcWiRgaPQjjBjBbbJZmwakt8=; b=er+muJI71Xard5EO7GqXt1gwtHwqYgVtxN6WAIy2EocdMMAYI7jTm8vyYdPCK8zXvHzxUm 84lqDh/YaVIQPW29KGk24fGId98opcrqh6ac1oxf+24m6mHUwGSOiA79xdf7/7OjRdnTHD c/47TeDNosuJJW0DFDqYNU5ajsqHL8c= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BE171AE0D; Wed, 23 Sep 2020 07:54:07 +0000 (UTC) Date: Wed, 23 Sep 2020 09:53:29 +0200 From: Michal Hocko To: Christian Brauner Cc: Tejun Heo , Peter Xu , Linus Torvalds , Jason Gunthorpe , John Hubbard , Leon Romanovsky , Linux-MM , Linux Kernel Mailing List , "Maya B . Gokhale" , Yang Shi , Marty Mcfadden , Kirill Shutemov , Oleg Nesterov , Jann Horn , Jan Kara , Kirill Tkhai , Andrea Arcangeli , Christoph Hellwig , Andrew Morton Subject: Re: [PATCH 1/4] mm: Trial do_wp_page() simplification Message-ID: <20200923075329.GC4887@dhcp22.suse.cz> References: <20200918164032.GA5962@xz-x1> <20200921134200.GK12990@dhcp22.suse.cz> <20200921141830.GE5962@xz-x1> <20200921142834.GL12990@dhcp22.suse.cz> <20200921143847.GB4268@mtj.duckdns.org> <20200921144355.mrzc66lina3dkfjq@wittgenstein> <20200921145537.GM12990@dhcp22.suse.cz> <20200921150450.3mjjb3p3jwgatn4v@wittgenstein> <20200921160643.GP12990@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200921160643.GP12990@dhcp22.suse.cz> 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 21-09-20 18:06:44, Michal Hocko wrote: [...] > Thanks a lot for this clarification! So I believe the only existing bug > is in documentation which should be explicit that the cgroup fd read > access is not sufficient because it also requires to have a write access > for cgroup.procs in the same directory at the time of fork. I will send > a patch if I find some time for that. I have reread the man page and concluded that the current wording is not bugy. It is referring to cgroups(7) which has all the information but it takes quite some to drill down to the important point. On the other hand there are many details (like delegation, namespaces) which makes it quite complex to be concise in clone(2) so it is very likely better to leave as it is. -- Michal Hocko SUSE Labs