swsusp and PSE

swsusp and PSE

[Nicolas Troncoso Carrere]

Hi,
I was trying out swsusp, but up bumped up with the issue that it needs PSE. 
I've been reading the source, but havent been able to get a grasp on why does 
it need PSE.
Could you enlighten me?

cheers
-- 
Nicolás Troncoso Carrère                        User #272312 counter.li.org
Estudiante Magíster en Ciencias de la Informática
Universidad Técnica Federico Santa María
http://www.alumnos.inf.utfsm.cl/~ntroncos

Re: swsusp and PSE

[Pavel Machek]

On Čt 01-06-06 10:17:22, Nicolas Troncoso Carrere wrote:
> Hi,
> I was trying out swsusp, but up bumped up with the issue that it needs PSE. 
> I've been reading the source, but havent been able to get a grasp on why does 
> it need PSE.
> Could you enlighten me?

W/o PSE, we are using pagetables during data copy, and we may
overwrite pagetable that is still used.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
_______________________________________________
linux-pm mailing list
linux-pm@lists.osdl.org
https://lists.osdl.org/mailman/listinfo/linux-pm

Re: swsusp and PSE

[Shaohua Li]

On Thu, 2006-06-01 at 22:24 +0800, Pavel Machek wrote:
> On Čt 01-06-06 10:17:22, Nicolas Troncoso Carrere wrote: 
> > Hi, 
> > I was trying out swsusp, but up bumped up with the issue that it
> needs PSE.  
> > I've been reading the source, but havent been able to get a grasp on
> why does  
> > it need PSE. 
> > Could you enlighten me?
> 
> W/o PSE, we are using pagetables during data copy, and we may 
> overwrite pagetable that is still used.
w/PSE pagetable might be overwritten too and data copy uses identity
mapping, overwrite pagetable doesn't harm to me. From my understanding,
PSE is incompatible with DEBUG_PAGEALLOC. swsusp can't work with
DEBUG_PAGEALLOC now, so it's likely we thought swsusp can't work w/o
PSE. currently DEBUG_PAGEALLOC is disabled with swsusp, the PSE check
could be deleted.
PS. we could make DEBUG_PAGEALLOC works with swsusp too.

Thanks,
Shaohua
_______________________________________________
linux-pm mailing list
linux-pm@lists.osdl.org
https://lists.osdl.org/mailman/listinfo/linux-pm

Re: swsusp and PSE

[Pavel Machek]

On Po 05-06-06 09:47:45, Shaohua Li wrote:
> On Thu, 2006-06-01 at 22:24 +0800, Pavel Machek wrote:
> > On Čt 01-06-06 10:17:22, Nicolas Troncoso Carrere wrote: 
> > > Hi, 
> > > I was trying out swsusp, but up bumped up with the issue that it
> > needs PSE.  
> > > I've been reading the source, but havent been able to get a grasp on
> > why does  
> > > it need PSE. 
> > > Could you enlighten me?
> > 
> > W/o PSE, we are using pagetables during data copy, and we may 
> > overwrite pagetable that is still used.
> w/PSE pagetable might be overwritten too and data copy uses identity
> mapping, overwrite pagetable doesn't harm to me. 

w/PSE, identity mapping is fully contained in top-level pagedir, and
that is properly marked nosave.

wo/PSE, you'd need to properly mark nosave not only top-level pagedir,
but also all the needed descendants. Not impossible, just a bit
tricky, see x86-64 version for inspiration.
								Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
_______________________________________________
linux-pm mailing list
linux-pm@lists.osdl.org
https://lists.osdl.org/mailman/listinfo/linux-pm