Re: [for-next 1/5] RDMA/bnxt_re: Enable RoCE on virtual functions

[Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

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On Fri, 2018-01-05 at 06:40 -0500, Devesh Sharma wrote:
> From: Selvin Xavier <selvin.xavier-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> 
> Currently, fifty percent of the total available resources
> are reserved for PF and remaining are equally divided among
> active VFs.
> 
> +/*
> + * Percentage of resources of each type reserved for PF.
> + * Remaining resources are divided equally among VFs.
> + * [0, 100]
> + */
> +#define BNXT_RE_PCT_RSVD_FOR_PF         50

This is a separate comment from the patch review itself.  But, are you
sure this is a good idea?  And especially are you sure that it should be
a compile time constant and not a runtime parameter?

I ask because it seems to me that usage of this stuff falls into one of
two categories:

1) All bare metal usage
2) SRIOV usage (in which case the bare metal OS does relatively little,
the SRIOV using clients do most of the work)

I guess I'm finding it hard to imagine a scenario where, when you do
have SRIOV VFs, that you don't want the majority of all resources being
used there.

I might suggest that you simply don't split resources at all.  Maybe do
something like filesystems do.  Let anyone at all take a resource until
you hit 95% utilization then only root can write to the filesystem.  In
this case it would be let both PFs and VFs use resources at will up
until you hit the 95% utilization threshold and then restrict resource
use to the PF.  That would make much more sense to me.

-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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