On 07/05/2012 05:09 PM, Johannes Weiner wrote:

In the very first review iteration of AutoNUMA, Peter argued that the
scheduler people want to use this flag in other places where they rely
on this thing meaning a single cpu, not a group of them (check out the
cpumask test in debug_smp_processor_id() in lib/smp_processor_id.c).

He also argued that preventing root from rebinding the numa daemons is
not critical to this feature at all.  And I have to agree.

Despite not being a scheduler expert, I'll have to side with that as
well. The thing I have in mind is: We have people whose usecase depend
on completely isolating cpus, with nothing but a specialized task
running on it. For those people, even the hard binding between cpu0 and
the timer interrupt is a big problem.

If you force a per-node binding of a kthread, you are basically saying
that those people are unable to isolate a node. Or else, that they have
to choose between that, and AutoNUMA. Both are suboptimal choices, to
say the least.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>