[ofa-general] OOM problem with ib_ipoib?

[Roland Dreier]

> The curious thing is that the OOM occurs even when the ib interfaces
> are _not even UP_, although the ib_ipoib module is loaded. So, I cannot
> see how it can be an allocation issue in such a case related to usage. Am I
> missing something here?

The IPoIB CM code allocates receive buffers even before the interface is brought
up.  Maybe the wrong thing to do, but that's how the code is now at least.

> As well, shouldn't the OS handle this transparently via the pdflush which
> will write out the data and free up memory? Or does the pdflush not
> distinguish between total memory and low memory so that a problem
> occurs (yet the OOM happens even when the interfaces are not UP!)?

You may really have no free lowmem... keep in mind that the linux mm really
does not behave well with 32G of RAM and a 32-bit kernel.  It's fundamentally
and insane config and so no one tunes for it.

 - R.