Re: Hibernation Redesign

From: Jeremy Fitzhardinge
Date: Mon Jul 09 2007 - 02:23:09 EST


Jeremy Maitin-Shepard wrote:
It would indeed be a pain for the new kernel to be loaded and have to
use discontiguous memory. The trick is, though, that this is not
necessary. Immediately before jumping to the new kernel, the first X
bytes (where X is the amount of memory the new kernel will get,
typically 16MB or 64MB) of physical memory are backed up into the
arbitrary discontiguous pages that are made available. This will not
take very long, because copying even 64MB of memory is extremely fast.
Then the new kernel is free to use the first X bytes of contiguous
physical memory. Problem solved.

You could also use the paravirt_ops pte hooks to create a mapping from linear "physical" addresses to actual machine pages. This is what a Xen kernel needs to do, and all the infrastructure will be in place shortly.

J
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