From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:40619 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751535Ab2K0Obc (ORCPT ); Tue, 27 Nov 2012 09:31:32 -0500 Date: Tue, 27 Nov 2012 09:31:31 -0500 From: "bfields@fieldses.org" To: Stanislav Kinsbursky Cc: "linux-nfs@vger.kernel.org" , "devel@openvz.org" Subject: Re: NFSd threads amount policy in containers context Message-ID: <20121127143131.GC27142@fieldses.org> References: <50B3941D.9030202@parallels.com> <20121126220849.GA18186@fieldses.org> <50B4740A.6000302@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 In-Reply-To: <50B4740A.6000302@parallels.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, Nov 27, 2012 at 12:04:26PM +0400, Stanislav Kinsbursky wrote: > 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? Yes, that sounds good, thanks! --b.