Re: Enabling peer to peer device transactions for PCIe devices
From: Serguei Sagalovitch
Date: Fri Nov 25 2016 - 12:59:47 EST
Well, I guess there's some consensus building to do. The existingAbout one application restriction: so it is per memory mapping? I assume
* Device DAX: which could work but the problem I see with it is that it
only allows one application to do these transfers. Or there would have
to be some user-space coordination to figure which application gets what
it should not be problem for one application to do transfer to the
simultaneously? Am I right?
May be we should follow RDMA MR design and register memory for p2p
transfer from user
What about the following:
a) Device DAX is created
b) "Normal" (movable, etc.) allocation will be done for PCIe memory and
CPU pointer/access will
c) p2p_mr_register() will be called and CPU pointer (mmap( on DAX
Device)) will be returned.
Accordingly such memory will be marked as "unmovable" by e.g. graphics
d) When p2p is not needed then p2p_mr_unregister() will be called.
What do you think? Will it work?