From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from relay.parallels.com ([195.214.232.42]:57269 "EHLO relay.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758215Ab2K0IEi convert rfc822-to-8bit (ORCPT ); Tue, 27 Nov 2012 03:04:38 -0500 Message-ID: <50B4740A.6000302@parallels.com> Date: Tue, 27 Nov 2012 12:04:26 +0400 From: Stanislav Kinsbursky MIME-Version: 1.0 To: "bfields@fieldses.org" CC: "linux-nfs@vger.kernel.org" , "devel@openvz.org" Subject: Re: NFSd threads amount policy in containers context References: <50B3941D.9030202@parallels.com> <20121126220849.GA18186@fieldses.org> In-Reply-To: <20121126220849.GA18186@fieldses.org> Content-Type: text/plain; charset="UTF-8"; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: 27.11.2012 02:08, bfields@fieldses.org пишет: > On Mon, Nov 26, 2012 at 08:09:01PM +0400, Stanislav Kinsbursky wrote: >> Hello. >> I would like to discuss how to control NFSd threads amount from >> container environment (is this particular case it means start of NFS >> server in network namespace different to init_net). >> >> So, I see three possible policies (let's assume, that there are two containers - one requested 3 NFSd threads and another one - 4 NFSd threads): >> 1) start as many threads, as requested. I.e 7 threads for specified >> case (simplest case, but probably this is to much - 100 containers >> will start ~800 threads by default). >> 2) start maximum number of requested threads. I.e. 4 threads for >> specified case (if NFSd server in container, requested 4 threads, >> will be stopped, then 3 thread will left working; will require some >> way to manage - rb tree of sorted list). >> 3) There could be some other (more flexible) policy: combine second >> one with running of one more thread for each second and further >> network namespace, started NFS server. I.e.: >> 1 net ns: 3 threads request = 3 threads started >> 2 net ns: 4 threads request = 4 + 1 (per-net thread: 1 net ns) = 5 threads started >> 3 net ns: 8 threads request = 8 + 2 (per-net threads: 2 net ns) = 10 threads started >> >> Bruce and community, what do you think about all this? > > I agree that options 2 or 3 seem more likely to be optimal. > > However, looking at the problems with, for example, getting race-free > shutdown correct: I'd *strongly* prefer that we start with 1, because I > think it will be simplest to get right. > > I'd rather put off figuring out how to scale to hundreds of containers > until after we demonstrate something simple and obviously correct. > Ok. Then I think we could implement even a better and simpler solution: make the whole nfsd_serv per network namespace. This solution is easy to implement, non-racy on shutdown and will give us a rather easy way to apply scheduler policy to NFSd threads (this will be most probably required in future). Does it sounds good to you? -- Best regards, Stanislav Kinsbursky