On 4/22/2014 9:23 AM, Christoph Hellwig wrote:
On Mon, Apr 21, 2014 at 06:02:14PM -0400, Chuck Lever wrote:
ALLPHYSICAL is not a safe memory registration mode because it
permits NFS servers to write anywhere in a client's memory. NFS
server bugs could result in client memory being overwritten.
This can be useful for embedded systems which do not support more
surgical RDMA memory registration and protection methods, or for
bring-up of new HCA hardware.
However, enterprise Linux distributions have expressed a desire to
disable it in production environments.
It's just as unsafe in embedded devices. I think it should go
For small IOs pattern, ALLPHYSICAL should outperform any registration method
in terms of IOP rate (simply because it doesn't do it).
Generally speaking, deployments that may prefer higher IOP rate in the cost
of a security do exist out there...
Sagi.
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