Re: [discuss] Re: [PATCH][Fix][Resend] Fix Bug #4959: Page tables corrupted during resume on x86-64 (take 3)

[Pavel Machek <pavel@suse.cz>]

Hi!

> > > > > The following patch fixes Bug #4959.  For this purpose it creates
> > > > > temporary page translation tables including the kernel mapping (reused)
> > > > > and the direct mapping (created from scratch) and makes swsusp switch
> > > > > to these tables right before the image is restored.
> > > > >
> > > > > The code that generates the direct mapping is based on the code in
> > > > > arch/x86_64/mm/init.c.
> > > >
> > > > Looks much better than before, but is there any reason you cannot
> > > > share the code with the mm/init.c code?
> > >
> > > I think so.  I have to make the temporary page tables nosavedata or set
> > > PG_nosave on them, so that swsusp doesn't overwrite them.  I'm not
> > > sure if I could do this cleanly if I used the code from mm/init.c directly.
> > 
> > Just pass a flag for that.
> 
> Well, the code in mm/init.c is only executed really early, before zones
> are initialized, and it uses alloc_low_page() to map memory.  Thus it seems
> I only could make my code be executed next to init_memory_mapping(),
> in which case I wouldn't be able to use page flags.  Apparently I'm missing
> something but now I'm too tired to think efficiently.

I guess Andi meant "add a parameter to those mm/init.c functions".

(Otoh, you have reserved area, anyway, just set all of it PG_nosave,
and you'll not need to modify mm/init.c stuff).
								Pavel
-- 
if you have sharp zaurus hardware you don't need... you know my address