Re: [LSF/MM TOPIC] Discuss least bad options for resolving longterm-GUP usage by RDMA

[Doug Ledford]

On Wed, 2019-02-06 at 12:20 -0800, Matthew Wilcox wrote:
> On Wed, Feb 06, 2019 at 03:16:02PM -0500, Doug Ledford wrote:
> > On Wed, 2019-02-06 at 11:40 -0800, Matthew Wilcox wrote:
> > > On Wed, Feb 06, 2019 at 07:16:21PM +0000, Christopher Lameter wrote:
> > > > though? If we only allow this use case then we may not have to worry about
> > > > long term GUP because DAX mapped files will stay in the physical location
> > > > regardless.
> > > 
> > > ... except for truncate.  And now that I think about it, there was a
> > > desire to support hot-unplug which also needed revoke.
> > 
> > We already support hot unplug of RDMA devices.  But it is extreme.  How
> > does hot unplug deal with a program running from the device (something
> > that would have returned ETXTBSY)?
> 
> Not hot-unplugging the RDMA device but hot-unplugging an NV-DIMM.

Is an NV-DIMM the only thing we use DAX on?


-- 
Doug Ledford <dledford@xxxxxxxxxx>
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