From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tejun Heo <tj@kernel.org>
Subject: Re: [PATCHv1 3/6] rdmacg: implements rdma cgroup
Date: Thu, 7 Jan 2016 15:28:18 -0500
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To: Parav Pandit <pandit.parav@gmail.com>
Cc: cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, lizefan@huawei.com, Johannes Weiner <hannes@cmpxchg.org>, Doug Ledford <dledford@redhat.com>, Liran Liss <liranl@mellanox.com>, "Hefty, Sean" <sean.hefty@intel.com>, Jason Gunthorpe <jgunthorpe@obsidianresearch.com>, Haggai Eran <haggaie@mellanox.com>, Jonathan Corbet <corbet@lwn.net>, james.l.morris@oracle.com, serge@hallyn.com, Or Gerlitz <ogerlitz@mellanox.com>, Matan Barak <matanb@mellanox.com>, raindel@mellanox.com, akpm@linux-foundation.org, linux-security-module@vger.kernel.org

Hello, Parav.

On Fri, Jan 08, 2016 at 01:55:09AM +0530, Parav Pandit wrote:
...
> Above functionality is achieved, by maintaining the map this tgid and
> associated original cgroup at try_charge(), uncharge() time.

Hmmm, what happens after the following?

1. A process allocates some rdma resources and get registered on the
   hash table.

2. The process gets migrated to a different cgroup.

3. The process allocates more rdma resources.

Which cgroup would the resources from #3 be attributed to?

> In alternate method,
> Its simple to store the pointer of rdma_cgroup structure in the IB
> resource structure and hold on reference count to rdma_cgroup.
> so that when its freed, uncharge_resource can accept rdma_cgroup
> structure pointer.

That'd be a lot more in line with how other controllers behave.

Thanks.

-- 
tejun