From mboxrd@z Thu Jan 1 00:00:00 1970 From: Haggai Eran Subject: Re: [PATCH 0/7] devcg: device cgroup extension for rdma resource Date: Tue, 8 Sep 2015 15:45:50 +0300 Message-ID: <55EED87E.3000408@mellanox.com> References: <1441658303-18081-1-git-send-email-pandit.parav@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1441658303-18081-1-git-send-email-pandit.parav-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Parav Pandit , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org, hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org, dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org Cc: corbet-T1hC0tSOHrs@public.gmane.org, james.l.morris-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org, ogerlitz-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, matanb-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, raindel-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, linux-security-module-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org On 07/09/2015 23:38, Parav Pandit wrote: > Currently user space applications can easily take away all the rdma > device specific resources such as AH, CQ, QP, MR etc. Due to which other > applications in other cgroup or kernel space ULPs may not even get chance > to allocate any rdma resources. > > This patch-set allows limiting rdma resources to set of processes. > It extend device cgroup controller for limiting rdma device limits. I don't think extending the device cgroup is the right place for these limits. It is currently a very generic controller and adding various RDMA resources to it looks out of place. Why not create a new controller for rdma? Another thing I noticed is that all limits in this cgroup are global, while the resources they control are hardware device specific. I think it would be better if the cgroup controlled the limits of each device separately. > With this patch, user verbs module queries rdma device cgroup controller > to query process's limit to consume such resource. It uncharge resource > counter after resource is being freed. This is another reason why per-device limits would be better. Since limits are reflected to user-space when querying a specific device, it will show the same maximum limit on every device opened. If the user opens 3 devices they might expect to be able to open 3 times the number of the resources they actually can. Regards, Haggai -- 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