Re: [openib-general] ipoib lockdep warning

From: Ingo Molnar
Date: Wed Jul 12 2006 - 05:45:46 EST



* Roland Dreier <rdreier@xxxxxxxxx> wrote:

> Hmm, good point.
>
> It sort of seems to me like the idr interfaces are broken by design.
[...]

> So, ugh... maybe the best thing to do is change lib/idr.c to use
> spin_lock_irqsave() internally?

i agree that the IDR subsystem should be irq-safe if GFP_ATOMIC is
passed in. So the _irqsave()/_irqrestore() fix should be done.

But i also think that you should avoid using GFP_ATOMIC for any sort of
reliable IO path and push as much work into process context as possible.
Is it acceptable for your infiniband IO model to fail with -ENOMEM if
GFP_ATOMIC happens to fail, and is the IO retried transparently?

Ingo
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