Date: Mon, 28 Nov 2016 15:24:52 -0700
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Serguei Sagalovitch <serguei.sagalovitch@amd.com>
Cc: Logan Gunthorpe <logang@deltatee.com>,
        Haggai Eran <haggaie@mellanox.com>,
        Christian K??nig <christian.koenig@amd.com>,
        Dan Williams <dan.j.williams@intel.com>,
        "Deucher, Alexander" <Alexander.Deucher@amd.com>,
        "linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
        "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "Kuehling, Felix" <Felix.Kuehling@amd.com>,
        "Bridgman, John" <John.Bridgman@amd.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "dri-devel@lists.freedesktop.org" <dri-devel@lists.freedesktop.org>,
        "Sander, Ben" <ben.sander@amd.com>,
        "Suthikulpanit, Suravee" <Suravee.Suthikulpanit@amd.com>,
        "Blinzer, Paul" <Paul.Blinzer@amd.com>,
        "Linux-media@vger.kernel.org" <Linux-media@vger.kernel.org>,
        Max Gurtovoy <maxg@mellanox.com>
Subject: Re: Enabling peer to peer device transactions for PCIe devices
Message-ID: <20161128222452.GA744@obsidianresearch.com>
References: <91d28749-bc64-622f-56a1-26c00e6b462a@deltatee.com>
 <20161124164249.GD20818@obsidianresearch.com>
 <3f2d2db3-fb75-2422-2a18-a8497fd5d70e@amd.com>
 <20161125193252.GC16504@obsidianresearch.com>
 <d9e064a0-9c47-3e41-3154-cece8c70a119@mellanox.com>
 <20161128165751.GB28381@obsidianresearch.com>
 <f3bb8372-ae2e-2f5e-5505-4ecaddbfb16e@deltatee.com>
 <0d3d56e2-4d2b-85b7-9487-b7ae2aaea610@amd.com>
 <c8c25265-9f59-f3d6-6249-07500e73930e@deltatee.com>
 <1ac2f9e7-f1ee-a2c9-0134-ffaa28c706af@amd.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1ac2f9e7-f1ee-a2c9-0134-ffaa28c706af@amd.com>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 614
Lines: 14

On Mon, Nov 28, 2016 at 04:55:23PM -0500, Serguei Sagalovitch wrote:

> >We haven't touch this in a long time and perhaps it changed, but there
> >definitely was a call back in the PeerDirect API to allow the GPU to
> >invalidate the mapping. That's what we don't want.

> I assume that you are talking about "invalidate_peer_memory()' callback?
> I was told that it is the "last resort" because HCA (and driver) is not
> able to handle  it in the safe manner so it is basically "abort" everything.

If it is a last resort to save system stability then kill the impacted
process, that will release the MRs.

Jason