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SubjectRe: [RFC PATCH 0/4 V2] introduce: livedump
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On Fri, 2012-05-25 at 18:12 +0900, YOSHIDA Masanori wrote:
> Live Dump is based on Copy-on-write technique. Basically processing is
> performed in the following order.
> (1) Suspends processing of all CPUs.
> (2) Makes pages (which you want to dump) read-only.
> (3) Resumes all CPUs
> (4) On page fault, dumps a page including a fault address.

Suppose a PF is in progress when all this happens, you mark all RO, then
an NMI happens, from the NMI context we'll generate another PF to update
a vmap area, this will again PF because you mucked about and marked
things RO.

You're now at 3 PFs, which is instant reboot.

I don't think this is going to work.



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