From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCHv12 0/3] rdmacg: IB/core: rdma controller support Date: Mon, 10 Oct 2016 09:20:14 -0400 Message-ID: <20161010132014.GD29742@mtj.duckdns.org> References: <1472632647-1525-1-git-send-email-pandit.parav@gmail.com> <20161005112206.GC9282@leon.nu> <20161010044623.GI9282@leon.nu> <20161010122545.GA27360@mtj.duckdns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Parav Pandit Cc: Leon Romanovsky , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma , Li Zefan , Johannes Weiner , Doug Ledford , Christoph Hellwig , Liran Liss , "Hefty, Sean" , Jason Gunthorpe , Haggai Eran , james.l.morris-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, Or Gerlitz , Matan Barak List-Id: linux-rdma@vger.kernel.org Hello, Parav. On Mon, Oct 10, 2016 at 06:43:59PM +0530, Parav Pandit wrote: > > Also, I don't get what you mean by using percentage and when people > > brought up this idea, it always has been stemming from > > misunderstanding. Can you please elaborate how percentage based > > proportional control would work? What would 100% mean when cgroups > > can come and go? > > When 100% is given to one cgroup, all resources of all type can be > charged by processes of that cgroup. > Resources are stateful resource. So when cgroup goes away, they go > back to global pool (or hw). > Giving 100% to two cgroups is configuration error anyway (or without config). That isn't proportional control. That's using percentage as the unit to implement absolute limits. Proportional control implies work conservation. > As you know weight configuration allows automatic increase/decrease of > resource to other cgroups when one of them go away, as opposed to > absolute value. How this is going to work in exact terms for stateful Hmm.... so are you saying that ti'd be work-conserving? But what does it mean to say "30%" and then have it all resources when there are no other users. Also, is it even possible to take back what have already been allocated and are in use? > Nop. Thats not true. > (a) Every new resource has to be defined in cgroup_rdma.h > (b) charge()/uncharge() has to happen by the cgroup for each. > (c) Letting drivers do will make things fall apart. There are no APIs > exposed either to let drivers know process cgroup either. There is no > intention either. > > (d) ratio means -if adapter has > 100 resources of type - A, > 80 resource of type - B, > > 10% for cgroup-1 means, > 10 resource of type - A > 8 resource of type - B So, this is not work-conserving. There's too much confusion here. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html