From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753672AbbIKTFn (ORCPT ); Fri, 11 Sep 2015 15:05:43 -0400 Received: from mail-yk0-f182.google.com ([209.85.160.182]:35939 "EHLO mail-yk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751351AbbIKTFl (ORCPT ); Fri, 11 Sep 2015 15:05:41 -0400 Date: Fri, 11 Sep 2015 15:05:34 -0400 From: Tejun Heo To: Parav Pandit Cc: Doug Ledford , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, lizefan@huawei.com, Johannes Weiner , Jonathan Corbet , james.l.morris@oracle.com, serge@hallyn.com, Haggai Eran , Or Gerlitz , Matan Barak , raindel@mellanox.com, akpm@linux-foundation.org, linux-security-module@vger.kernel.org Subject: Re: [PATCH 0/7] devcg: device cgroup extension for rdma resource Message-ID: <20150911190534.GT8114@mtj.duckdns.org> References: <20150908152340.GA13749@mtj.duckdns.org> <20150910164946.GH8114@mtj.duckdns.org> <20150910202210.GL8114@mtj.duckdns.org> <20150911040413.GA18850@htj.duckdns.org> <55F25781.20308@redhat.com> <20150911145213.GQ8114@mtj.duckdns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Parav. On Fri, Sep 11, 2015 at 10:17:42PM +0530, Parav Pandit wrote: > IO controller and applications are mature in nature. > When IO controller throttles the IO, applications are pretty mature > where if IO takes longer to complete, there is possibly almost no way > to cancel the system call or rather application might not want to > cancel the IO at least the non asynchronous one. I was more talking about the fact that they allow resources to be consumed when they aren't contended. > So application just notice lower performance than throttled way. > Its really not possible at RDMA level with RDMA resource to hold up > resource creation call for longer time, because reusing existing > resource with failed status can likely to give better performance. > As Doug explained in his example, many RDMA resources as its been used > by applications are relatively long lived. So holding ups resource > creation while its taken by other process will certainly will look bad > on application performance front compare to returning failure and > reusing existing one once its available or once new one is available. I'm not really sold on the idea that this can be used to implement performance based resource distribution. I'll write more about that on the other subthread. Thanks. -- tejun