[openib-general] [PATCH for-2.6.18] IB/cma: option to limitMTU to 1K

[Michael S. Tsirkin]

Quoting r. Hal Rosenstock <halr at voltaire.com>:
> > If I understood Michael's comment properly, this will have the side
> > effect that IPoIB won't work since IPoIB requires 2K MTUs.  As far as
> > I know, there is no way to specify whether a path is needed for UD vs.
> > RC in the path query.
> 
> I don't know how either. I don't think it can be done (at least
> currently per the standard).

We don't really need to know whether path is for RC or UD QP.
IPoIB needs MTU >= 2K so it should set mtu selector to >= 2K.
In this case SM will return path with MTU >= 2K.
CMA will not set mtu selector and then SM will choose MTU for best performance.

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MST