Re: [Lse-tech] Minutes from LSE Con Call

[William Lee Irwin III]

On Fri, Jul 12, 2002 at 11:38:06AM -0700, Hanna Linder wrote:
> 8. Daniel asked about seeing results of rmap on a numaq.
> Martin got distracted but will get back to getting some
> results.

On elm3b17 I found more 2.5.25 vs. NUMA-Q issues and got workarounds
for booting while doing work on stuffing pte_chains into highmem:

(1) cpu_init() heisenbug that goes away when adding printk's
	I just added the extra printk's and moved on
(2) in_interrupt() is racy and needs to disable preemption
	while checking per-cpu counters. The trivial fix.
(3) CONFIG_PREEMPT calls preempt_schedule() on secondaries
	before they're ready, and the exception is flagged as
	no vm86_info: BAD
	Didn't want to go to deep into it at 3AM and disabled preempt.

The usual ioremap()/smp_call_function() deadlock, irqbalance
plugging unreachable cpu's into ioapics, bio splitting to make
qlogicisp happy, and MAX_IO_APICS things are still needed.

So I guess the "real fixes" need to get found at some point and
propagated out to maintainers. hpa and mochel are on cpu_init(),
and rml should be on preempt vs. printk and in_interrupt(). axboe
has already got bio splitting ready and no idea about the MAX_IO_APICS
and getting irqbalance fixes past mingo doesn't look easy.

Cheers,
Bill