Re: Kernel fast memory registration API proposal [RFC]

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

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On 07/14/2015 01:08 PM, Jason Gunthorpe wrote:
> On Tue, Jul 14, 2015 at 07:46:50PM +0300, Sagi Grimberg wrote:
>> Which drivers doesn't support FRWR that we need to do other things?
>> ipath - depracated
> 
> We have permission to move this to staging and then RM it, so yay!

Correct.

>> mthca - soon to be deprecated
> 
> This one I have a problem with. There is alot of mthca hardware out
> there, it feels wrong to nuke it.. If we can continue to support the
> FMR scheme it uses transparently, that would be excellent.
> 
> I'm not hearing a strong reason why that shouldn't be the case...

I'm not so sure about deprecating mthca either.  There are still a
number of people I know that like to buy cheap SDR/DDR switches on EBay
and pair them with cheap mthca cards and have cheap 10/20GBit/s home
networks.  We have a couple people inside Red Hat that occasionally tell
people what to look for on EBay to do just this.

>> ehca - Not sure what is going on there. they only have phys_mr
>>        anyway, which just lost its only caller in the kernel
> 
> I thought it supported fmr:
> 
> drivers/infiniband/hw/ehca/ehca_main.c: shca->ib_device.alloc_fmr           = ehca_alloc_fmr;
> drivers/infiniband/hw/ehca/ehca_main.c: shca->ib_device.map_phys_fmr        = ehca_map_phys_fmr;
> drivers/infiniband/hw/ehca/ehca_main.c: shca->ib_device.unmap_fmr           = ehca_unmap_fmr;
> drivers/infiniband/hw/ehca/ehca_main.c: shca->ib_device.dealloc_fmr         = ehca_dealloc_fmr;
> 
> ?
> 
> I'm not sure what the status of ehca is, but I somehow suspect any
> remaining users are going to be on an old vendor kernel forever..

Nothing of note has been done on ehca for a long time, and I wouldn't be
surprised if there is some bit rot in this driver.  We need to speak
with IBM, but I think it's a candidate for future removal.

-- 
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
              GPG KeyID: 0E572FDD



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