Messages in this thread | | | From | (Eric W. Biederman) | Subject | Re: [PATCH 2.6.21 review I] [11/25] x86: default to physical mode on hotplug CPU kernels | Date | Sun, 11 Feb 2007 04:13:02 -0700 |
| |
Andi Kleen <ak@suse.de> writes:
> From: Ingo Molnar <mingo@elte.hu> > > Default to physical mode on hotplug CPU kernels. Furher simplify and clean up > the APIC initialization code.
Where is the code that the subject describes?
I have two problems here.
- I don't see anything handling the hotplug case, and forcing us to physical mode. - Ingo's other patch asserts that hotplug should be made to handle logical deliver mode.
With logical deliver mode the experimental evidence is that the destination cpu is a hint, and you can arrive at a cpu that is not in your cpu mask. Now I only saw that problem on hyperthreaded cpus but we didn't have the code enabled long enough to see it in other cases.
Maybe if I can finish getting irq migration back into process context, and someone verifies that the cpu disable in the hotplug path actually disables the cpu/hyperthread instead of sitting in a hlt loop. We won't have a problem. But broadcast ipis and irqs that don't go where you tell them to are things we need to be very careful with.
Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |