From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: cgroups(7): documenting cgroups v2 thread mode Date: Tue, 9 Jan 2018 23:52:57 +0100 Message-ID: <79c80f45-1290-c096-c384-6379b56d9239@gmail.com> References: <20180109211000.GT3668920@devbig577.frc2.facebook.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=cc:subject:to:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=yR94/5tKkpZd5fzNSZFAyfMubiCOFFWnc1rtDkL9Mo8=; b=tT+FsjfG84Qqcgpci1Rd2fc1xU7ceGVtWyeP8ZpPGaAoD/9E8LLYqon4CVKNDjvbWx mcAODxLNg7ZM1BVVw1QBLs3SAoIWva8da1MbkEgsUYnoCzVZL1KfbA7VkZARMoi/S+1r NT1lcsFkfrJ94QTphOIUgLV1Lt53vPwU+V9PQyb3FvAxTNLT2IJJBvOPZnVkZGjacq9s 9E8oBt2BAVsqhlueQ5yhoM0hONCh8pXLvufqcPnS5fIE6px5ifyJptLJJYB9G2UTvy0+ UvWqAUYId2PAkg2Mm63B6JDUK1Q0kwovtdXLUDFUXQqswAvF7XefvFa6jEagqJibrkn7 Rpkw== In-Reply-To: <20180109211000.GT3668920-4dN5La/x3IkLX0oZNxdnEQ2O0Ztt9esIQQ4Iyu8u01E@public.gmane.org> Content-Language: en-US Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="utf-8" To: Tejun Heo Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Peter Zijlstra , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, lkml , linux-man , "Serge E. Hallyn" , Mike Galbraith , Li Zefan , Ingo Molnar , Paul Turner , kernel-team-b10kYP2dOMg@public.gmane.org, Andy Lutomirski , Johannes Weiner , Lauro Venancio , Waiman Long On 01/09/2018 10:10 PM, Tejun Heo wrote: > Hello, > > On Tue, Jan 02, 2018 at 07:24:01PM +0100, Michael Kerrisk (man-pages) wrote: >> 2. We write the string "threaded" to each of the domain invalid >> cgroups under y, in order to convert them to the type >> threaded. As a consequence of this step, all threads under >> the threaded root now have the type threaded and the >> threaded subtree is now fully usable. The requirement to >> write "threaded" to each of these cgroups is somewhat cum‐ >> bersome, but allows for possible future extensions to the >> thread-mode model. >> >> ┌─────────────────────────────────────────────────────┐ >> │FIXME │ >> ├─────────────────────────────────────────────────────┤ >> │Re the preceding paragraphs... Are there other rea‐ │ >> │sosn for the (cumbersome) requirement to write │ >> │'threaded' to each of the cgroup.type files in the │ >> │threaded subtrees? Tejun Heo mentioned the follow‐ │ >> │ing: │ >> │ │ >> │ Consistency w/ the cgroups right under the root │ >> │ cgroup. Because they can be both domains and │ >> │ threadroots, we can't switch the children over │ >> │ to thread mode automatically. Doing that for │ >> │ cgroups further down in the hierarchy would be │ >> │ really inconsistent. │ >> │ │ >> │But, it's not clear to me how "Doing that for │ >> │cgroups further down in the hierarchy would be │ >> │really inconsistent", since in the current implemen‐ │ >> │tation, those same thread groups are converted to │ >> │"domain invalid" type. What am I missing? │ >> └─────────────────────────────────────────────────────┘ > > Yeah, I was confused with an earlier varient where we were marking > threaded domains instead of threaded roots. It's mostly about future > extensibility (especially as Waiman was proposing related changes > there) and not doing things automatically / recursively if possible. Okay. > Looks good to me. Thanks for the review. Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html