[patch 0/4] CPU Hotplug support for X86_64

Ashok Raj
2005-05-24T08:29:34Z

[Oops: This is correct version: i send from the wrong directory earlier]
[Sorry about that spam... now i thin i know how to use quilt :-)]

This implements cpu hotplug support for X86_64.
Modified after initial feedback from Andi.

[PS: hopefully subject is now fixed with different subject lines]

Seems to hold up for make -j, with online/offline activity.

The series of patches are split as follows:

1. initcall cleanup
- Left __cpuinit cases as before per Andi
- Added a few new ones, and removed couple that could stay __init
even with cpu hotplug.
2. Core logical online/offline of cpus
- start with maxcpus=1, and then echo 1 to /sys/devices/system/online
- Can also bringup all cpus and then bring up/down all but cpu0.
- Also tested with numa=fake=2
3. Cleanup sibling map for cpu hotplug support.
4. Dont use IPI broadcast in smp_call_function() when using CPU hotplug.
Hopefully this is some reasonable middle ground starting point.
- Dont let a new cpu respond to IPI's.
- Automaticaly selected if CPU hotplus is choosen.
- Can also be turned on cmdline via safe_ipi=1

TBD:

1. Track down CONFIG_SCHED_SMT Oops with both cpu up/down.
2. Test on real NUMA hw.

Cheers,
Ashok Raj
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