Re: Excessive memory usage when infiniband config is enabled

Konstantin Taranov
2024-05-07T13:32:59Z

> Hello Leon,
>
> I feel that it's a bug because I don't understand why is this module/option
> allocating 6GB of RAM without any explicit configuration or usage from us.
> It's also worth mentioning that we are using the default linux-image from
> Debian bookworm, and it took us a long time to understand the reason
> behind this memory increase by bisecting the kernel's config file.
> Moreover the documentation of the module doesn't mention anything
> regarding additional memory usage, we're talking about an increase of 6Gb
> which is huge since we're not using the option.
> So is that an expected behavior, to have this much increase in the memory
> consumption, when activating the RDMA option even if we're not using it ? If
> that's the case, perhaps it would be good to mention this in the
> documentation.
>
> Thank you
>

Hi Brian,

I do not think it is a bug. The high memory usage seems to come from these lines:
rsrc_size = irdma_calc_mem_rsrc_size(rf);
rf->mem_rsrc = vzalloc(rsrc_size);

inside of irdma_initialize_hw_rsrc function. You can read the code of
irdma_calc_mem_rsrc_size to understand the 6GB memory usage.

You can ask developers of irdma to optimize memory usage.
Btw., module is loaded == module is used. There is no "loaded and unused".

Konstantin