[ofa-general] limit on memory registration

[Dotan Barak]

Rui Machado wrote:
> Withouth wanting to abuse on your generosity :) :
>
>   
>>>> :) yep sorry.
>>>> The value for max_mr_size is 18446744073709551615 (can this one be ? )
>>>> Again, how do I decode this?
>>>>         
> What about the huge number above?  It is much bigger than 16GB (my
> current limit).
> Does this mean my only take should be on the num_mtt parameter and try
> to do as you suggested? (reducing on  the rest)
>   
This number is the size of the maximum continigues block which can be 
registered,
it is a number of bytes (you can decode it in hex, and it will look like 
0xffffffffffffffff)
>   
>>>> Ok. And is there a limit?
>>>> And out of curiosity, how does this calculation gets done? I mean, can
>>>> I take the values and say: Ok, with this num_mtt we can go up to X?
>>>>
>>>>         
>> I guess there is an upper limit (device specific) but since i don't have an
>> available data sheet for this device
>> i can't tell you what it is.
>>     
>
> I guess you can't find that online or?
>   
not that i know of (sorry)
>   
>>> Tried with the module parameter but not sucessfully. I get errors like
>>>
>>> ib_mthca 0000:23:00.0: Failed to initialize memory region table, aborting.
>>> or
>>> ib_mthca: Invalid value 1048580 for num_mtt in module parameter.
>>> ib_mthca: Corrected num_mtt to 2097152.
>>>
>>> I guess I'm just shooting in the dark :)
>>>
>>>       
>> I remember that i saw that in the past (i think that the problem was kmalloc
>> of more than 128K..)
>> Can you try to decrease the number of the resources that you don't need
>> (MRs/CQs/QPs/SRQs) using the
>> module parameters, i think that this MAY help you.
>>     
>
> I will try!
>
> Thanks for the generosity :D
>   

Don't mention it...
Dotan