On 10/30/2017 10:11 AM, Sagi Grimberg wrote:
Idan,
NVMe over Fabrics in its secure "register_always" mode
registers and invalidates the user buffer upon each IO.
The protocol enables the host to request the susbsystem
to use SEND WITH INVALIDATE operation while returning the
response capsule and invalidate the local key
(remote_invalidation).
In some HW implementations, the local network adapter may
perform better while using local invalidation operations.
This is a device quirk and if you want to optimize for this
you need to expose it via verbs interface. We won't add a module
parameter for implementation specific stuff.
After our discussion yesterday I was thinking it may be better to hide
it within the nvme host driver while having a messages size threshold for
using send_with_invalidate. To make it device agnostic we will need
to come out with an idea of how to expose such limitation.
Note that we currently need to rework the case where we use local
invalidates and properly wait for them to complete.
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