Re: [LSF/MM TOPIC] Discuss least bad options for resolving longterm-GUP usage by RDMA
From: Doug Ledford
Date: Wed Feb 06 2019 - 15:50:48 EST
On Wed, 2019-02-06 at 12:49 -0800, Matthew Wilcox wrote:
> On Wed, Feb 06, 2019 at 03:47:53PM -0500, Doug Ledford wrote:
> > On Wed, 2019-02-06 at 12:41 -0800, Matthew Wilcox wrote:
> > > On Wed, Feb 06, 2019 at 03:28:35PM -0500, Doug Ledford wrote:
> > > > On Wed, 2019-02-06 at 12:20 -0800, Matthew Wilcox wrote:
> > > > > Not hot-unplugging the RDMA device but hot-unplugging an NV-DIMM.
> ^^^ I think you missed this line ^^^
Indeed, I did ;-)
> > You said "now that I think about it, there was a desire to support hot-
> > unplug which also needed revoke". For us, hot unplug is done at the
> > device level and means all connections must be torn down. So in the
> > context of this argument, if people want revoke so DAX can migrate from
> > one NV-DIMM to another, ok. But revoke does not help RDMA migrate.
> > If, instead, you mean that you want to support hot unplug of an NV-DIMM
> > that is currently the target of RDMA transfers, then I believe
> > Christoph's answer on this is correct. It all boils down to which
> > device you are talking about doing the hot unplug on.
Doug Ledford <dledford@xxxxxxxxxx>
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