[openib-general] Re: [PATCH 1/2] mthca support for max_map_per_fmr device attribute

[Michael S. Tsirkin]

Quoting r. Or Gerlitz <ogerlitz at voltaire.com>:
> Subject: Re: [PATCH 1/2] mthca support for max_map_per_fmr device attribute
> 
> Roland Dreier wrote:
> >    Or> When "requests" come fast enough, there's a window in time
> >    Or> when there's an unmapping of N FMRs running at batch, but out
> >    Or> of the remaining N FMRs some are already dirty and can't be
> >    Or> used to serve a credit. So the app fails temporally... So,
> >    Or> setting the watermark to 0.5N might solve this, but since
> >    Or> enlarging the number of remaps is trivial, i'd like to do it
> >    Or> first.

You will still be limited wrt the number of remaps in memfree architecture.
And the memory registration code is hard enough to stress test.
So I have to say setting the watermark at 0.5N makes much more sense to me.

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MST