Posted Dec 15, 2005 9:44 UTC (Thu) by dw
Parent article: SMP alternatives
Please excuse my ignorance of kernel development, but I don't understand how this can be made to work safely. I am not sure under which conditions CPU hotplug events are processed, but I would imagine that at that time numerous locks in the kernel would be in the locked state.
If the CPU hotplug code causes the unlock functions to become a NOOP, then after the event has been processed, any scheduled tasks that perform an unlock of an existing lock will not cause any change in the state of the kernel.
If the kernel is then patched for SMP again, and numerous locks which were 'unlocked' by tasks running under the non-SMP kernel are actually still marked in memory as locked, would that not cause severe system instabilty or a deadlock condition?
Again, I only know the kernel by concept, and have never written a line of code for it. Excuse my ignorance. :)
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