no-snoop flag in memory registration?

no-snoop flag in memory registration?

[Klaus Wacker]

Hi all,
we are implementing a Linux/RDMA solution based on Mellanox/RoCE. Our
memory registration is done via "ib_get_dma_mr()".
During a problem follow-up someone asked us about the "no-snoop" flag and
how it is set during memory registration in Linux. I digged into
drivers/net/ethernet/mellanox/mlx4/mr.c, to find some MLX4_MPT_FLAGS_
visible there. Nothing seems to be related to a "no-snoop" flag.
Can anybody shed some light on this, whether we can set the so called
"no-snoop" flag, or is that beyond the scope of Linux support.

Kind regards
Klaus Wacker
IBM Systems &Technology Group, Systems Software Development
SW Linux on System z Dev & Service
Phone:  +49-7031-16-3779   IBM Deutschland  E-Mail:  kdwacker-tA70FqPdS9Zhl2p70BpVqQ@public.gmane.orgm
Schoenaicher Str. 220   71032 Boeblingen   Germany
IBM Deutschland Research & Development GmbH / Vorsitzende des
Aufsichtsrats: Martina Koederitz
Geschäftsführung: Dirk Wittkopp
Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart,
HRB 243294

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Re: no-snoop flag in memory registration?

[Or Gerlitz]

On 23/10/2012 16:32, Klaus Wacker wrote:
> we are implementing a Linux/RDMA solution based on Mellanox/RoCE. Our memory registration is done via "ib_get_dma_mr()". During a problem follow-up someone asked us about the "no-snoop" flag and how it is set during memory registration in Linux.

Can you describe the problem you are trying to solve and what is the 
semantics you are looking for with "no snoop" -- which snooping and by 
what entity.

Or.



> I digged into
> drivers/net/ethernet/mellanox/mlx4/mr.c, to find some MLX4_MPT_FLAGS_
> visible there. Nothing seems to be related to a "no-snoop" flag.
> Can anybody shed some light on this, whether we can set the so called
> "no-snoop" flag, or is that beyond the scope of Linux support.
>
> Kind regards
> Klaus Wacker
> IBM Systems &Technology Group, Systems Software Development
> SW Linux on System z Dev & Service
> Phone:  +49-7031-16-3779   IBM Deutschland  E-Mail:  kdwacker-JZgbryFSZvw@public.gmane.orgcom
> Schoenaicher Str. 220   71032 Boeblingen   Germany
> IBM Deutschland Research & Development GmbH / Vorsitzende des
> Aufsichtsrats: Martina Koederitz
> Geschäftsführung: Dirk Wittkopp
> Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart,
> HRB 243294
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

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