[Crash-utility] handling missing kdump pages in diskdump format

[Dave Anderson]

Vivek Goyal wrote:

>
> > =====================================
> > Can ELF Dumpfiles Solve This Problem?
> > =====================================
> >
> > To achieve correctness with ELF dumpfiles, one could perhaps remap the
> > four types of pages to the three types of ELF representations so that
> > "A) Not In The Address Space" and "B) Excluded Type" were both mapped
> > to "1) Not In The Address Space".  Then "C) Zero Content" would map
> > to "2) Not In The File, Zero Fill".  You would lose the ability to
> > know if a page were missing because it was never in the address space
> > in the first place, or because it was excluded because of its type.
> > But if you read a zero, you'd know it really was a zero.
> >
>
> I think this is the way to go. Why would I like to know if a page was
> never present or mkdumpfile filtered it out? I think we can live with that
> and lets just not create any sort of mapping for excluded pages in finally
> generated ELF headers.
>

If "Excluded Type" pages were mapped as "Not in The Address Space",
aren't you going to end up with an absurd number of small PT_LOAD
segments?  I believe the original intent was to avoid that.

Dave