Re: [linux-pm] Proposal for a new algorithm for reading & writinga hibernation image.

From: Nigel Cunningham
Date: Thu Jun 03 2010 - 04:14:40 EST


Hi.

On 30/05/10 15:25, Pavel Machek wrote:
Hi!

2. Prior to writing any of the image, also set up new 4k page tables
such that an attempt to make a change to any of the pages we're about to
write to disk will result in a page fault, giving us an opportunity to
flag the page as needing an atomic copy later. Once this is done, write
protection for the page can be disabled and the write that caused the
fault allowed to proceed.

Tricky.

page faulting code touches memory, too...

Yeah. I realise we'd need to make the pages that are used to record the faults be unprotected themselves. I'm imagining a bitmap for that.

Do you see any reason that it could be inherently impossible? That's what I really want to know before (potentially) wasting time trying it.

Regards,

Nigel
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