Re: Demand paging for memory regions (was Re: MMU Notifiers V6)

From: Steve Wise
Date: Tue Feb 12 2008 - 17:02:44 EST


Roland Dreier wrote:
[Adding general@xxxxxxxxxxxxxxxxxxxxx to get the IB/RDMA people involved]

This thread has patches that add support for notifying drivers when a
process's memory map changes. The hope is that this is useful for
letting RDMA devices handle registered memory without pinning the
underlying pages, by updating the RDMA device's translation tables
whenever the host kernel's tables change.

Is anyone interested in working on using this for drivers/infiniband?
I am interested in participating, but I don't think I have enough time
to do this by myself.

I don't have time, although it would be interesting work!


Also, at least naively it seems that this is only useful for hardware
that has support for this type of demand paging, and can handle
not-present pages, generating interrupts for page faults, etc. I know
that Mellanox HCAs should have this support; are there any other
devices that can do this?


Chelsio's T3 HW doesn't support this.


Steve.
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