Re: [tip:x86/urgent] x86-32: Restore irq stacks NUMA-awareallocations

From: Cyrill Gorcunov
Date: Fri Oct 29 2010 - 16:59:23 EST


On Fri, Oct 29, 2010 at 10:53:07PM +0200, Eric Dumazet wrote:
> Le samedi 30 octobre 2010 à 00:28 +0400, Cyrill Gorcunov a écrit :
> > On Fri, Oct 29, 2010 at 08:32:26PM +0200, Peter Zijlstra wrote:
> > > On Fri, 2010-10-29 at 06:43 +0000, tip-bot for Eric Dumazet wrote:
> > > > + irqctx = page_address(alloc_pages_node(cpu_to_node(cpu),
> > > > + THREAD_FLAGS,
> > > > + THREAD_ORDER));
> > >
> > > Shouldn't we be checking for a NULL return from alloc_pages_node()
> > > before calling page_address() on it?
> > > --
> >
>
> I didnt check for NULL because original code was not either.
>
> If you cannot allocate memory for the IRQ stack, only choice is to crash
> anyway.
>
> Adding BUG_ON() is not that helpful in this respect.
>

I believe it was a nit in first place, so the BUG_ON simply tells to code
readers that we knew the NULL can happen here but there is simply no way
to continue then.

Cyrill
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/