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]:57613 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755818Ab2KZWIz (ORCPT ); Mon, 26 Nov 2012 17:08:55 -0500 Date: Mon, 26 Nov 2012 17:08:49 -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: <20121126220849.GA18186@fieldses.org> References: <50B3941D.9030202@parallels.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <50B3941D.9030202@parallels.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: 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. --b.