Re: Re: standby to disk transition

[Dave Jones <davej@redhat.com>]

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On Mon, Mar 13, 2006 at 10:24:20PM +0100, Pavel Machek wrote:

 > > if suspend-to-disk is fast enough, you could just *always* write
 > > to disk, even if we're doing S3.  If power runs out, you then have a
 > > valid resume image on-disk.  iirc, this is what Windows does.
 > 
 > Yep, I call that suspend-to-both. It is planned, but not really
 > trivial, and I'm a little busy. If someone wants to help....

I was thinking a few days ago. With your move of all this stuff to
userspace, if it was done in multiple stages, we could implement
a form of checkpointing this way.

So instead of doing the 'suspend to disk/ram' after 'write out all pages',
we just continue.

Why is this useful ?  We've seen bugs reported that only ever bite customers
after they've run their workload for a month.  Now, if they had a means
of checkpointing, then when it crashes, they could capture the last image
that landed somewhere, and set that up for more tests/monitoring with kprobes etc
and reproduce those hard-to-reproduce bugs a lot faster.

		Dave

-- 
http://www.codemonkey.org.uk

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