Because advertising of a MR (ie telling the peer about your rkey/stag,
offset and length) is application-specific and can be done out of band,
or in band as simple SEND/RECV payload. Either way, the driver has no
way of tracking this because the protocol used is application-specific.
Yes, _if_ the driver could track this.
And _if_ the rdma API and paradigm was such that the kernel/driver could
keep track, then remote revokations of MR tags could be supported.
Stevo
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