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SubjectRe: [PATCH] CPU hot swap for 2.4.3 + s390 support
Date

cw@f00f.org said:
> How do you relocate
> -- pages which are mlocked without violating RT contraints?
> -- pages which contain kernel pointers and might be accessed from
> interrupt context?

Those two are the same problem, essentially. You have to copy the page,
then map it into the same virtual address (be that userspace or
kernelspace) as the old one. Mark the page readonly when you start to copy
it, and have a fault handler which immediately marks it writable and
returns. If the source is writable by the time you've finished the copy,
repeat.

If you have to repeat yourself more than $n times, you're probably
experiencing livelock. At that point, do what Rik said - to hell with the
RT constraints, disable interrupts and do the copy. At least your cache is
warm :)

--
dwmw2


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