Re: [PATCH 02/23] Record & display i/o speed post resume.

[Rafael J. Wysocki]

On Monday, September 27, 2010, Nigel Cunningham wrote:
> Hi.
> 
> On 28/09/10 06:49, Rafael J. Wysocki wrote:
> > On Monday, September 27, 2010, Nigel Cunningham wrote:
...
> >> Well then, for now, let's drop that patch then. At least it's got us the
> >> numbers we needed to see these patches are useful. Longer term, I'll do
> >> what I do in TuxOnIce and allocate a page while writing the image, store
> >> it's location in the image header and use it the transfer information
> >> from the boot kernel to the resumed kernel. (Essentially the same thing,
> >> except without the special section).
> >
> > The problem is that on x86_64 the boot kernel may be completely different
> > from the image kernel (different version, different configuration), so there is
> > no guarantee that your page frame allocated while writing the image would be
> > available to the boot kernel (it may contain the kernel code, for example).
> >
> > You'd really need to replace one of the image pages with  something prepared
> > while the image was being read.  For that, you'd need to allocate a page before
> > creating the image and pass its PFN in the image header.
> 
> Yes - that's what I'm doing. Maybe that's why the __nosavedata changes 
> you mentioned above haven't bitten me.

Well, other than that, the majority of people don't know about that change and
they still use the same kernel for boot/image. :-)

Thanks,
Rafael
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