Re: NUMA-Q breakage 2/7 xquad_portio ioremap deadlock

From: William Lee Irwin III (wli@holomorphy.com)
Date: Fri Jul 12 2002 - 18:04:02 EST


>> The cpu_online_map stuff for hotplug cpu created a brand new bootstrap
>> ordering problem for NUMA-Q. The mmapped portio region needs to be
>> ioremapped early but ioremap attempts to do TLB shootdown, and
>> smp_call_function() (called by flush_tlb_all()) deadlocks when
>> cpu_online_map is uninitialized.

On Fri, Jul 12, 2002 at 03:58:50PM -0700, Martin J. Bligh wrote:
> Would it be slightly less of a hack if we just move the ioremap down below
> set_bit(0, &cpu_online_map); later on in smp_boot_cpus ? Untested patch
> below. As long as we set up the xquad_portio remap before any other cpus
> are online, I can't see it matters exactly when we do it ....
> Either that, or we just define cpu_online_map to be =1 to start with.
> M.

This looks better than fiddling with smp_call_function().

Cheers,
Bill
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