[PATCH] powerpc: add Book E support to 64-bit hibernation

[Scott Wood]

On 04/06/2013 10:01:45 PM, Wang Dongsheng-B40534 wrote:
> 
> 
> > -----Original Message-----
> > From: Wood Scott-B07421
> > Sent: Thursday, April 04, 2013 4:16 AM
> > To: Wang Dongsheng-B40534
> > Cc: Wood Scott-B07421; Johannes Berg; linuxppc-dev at lists.ozlabs.org
> > Subject: Re: [PATCH] powerpc: add Book E support to 64-bit  
> hibernation
> >
> > On 04/03/2013 12:36:41 AM, Wang Dongsheng-B40534 wrote:
> > >
> > >
> > > > -----Original Message-----
> > > > From: Wood Scott-B07421
> > > > Sent: Wednesday, April 03, 2013 8:35 AM
> > > > To: Wang Dongsheng-B40534
> > > > Cc: Wood Scott-B07421; Johannes Berg;  
> linuxppc-dev at lists.ozlabs.org
> > > > Subject: Re: [PATCH] powerpc: add Book E support to 64-bit
> > > hibernation
> > > >
> > > > On 04/02/2013 12:28:40 AM, Wang Dongsheng-B40534 wrote:
> > > > > Hi scott & Johannes,
> > > > >
> > > > > Thanks for reviewing.
> > > > >
> > > > > @scott, About this patch, could you please help ack this  
> patch?
> > > >
> > > > Please investigate the issue of whether we are loading kernel  
> module
> > > > code in this step, and whether cache flushing is needed as a  
> result.
> > > >
> > > Sorry, I am not very clear what you mean.
> > > When the kernel boot end, modprobe some xx.ko?
> >
> > Suppose, before the kernel was suspended, modules had been loaded.   
> At
> > what point do those modules get restored, and when does the cache  
> get
> > flushed?
> >
> Before the kernel was suspended, modules had been loaded, the modules  
> is
> already in memory.

They *were* in memory, until the hardware was powered down.

> And /lib/modules/* is belong to vfs.

Huh?  I'm talking about modules that have been loaded, not where in the  
filesystem they were loaded from.  Loading a module is not like  
mmap()ing a file.

> When suspend to disk, all used pages will be saved.(Include VFS,  
> Loaded modules)
> When restore, the kernel will not modprobe again.

Of course it won't modprobe again.  Still, at some point during the  
resume process, the code has to be loaded from disk into RAM.  What I  
don't know is if this is where that happens.

> The non-bootcpu will restore all pages.(Include VFS, Loaded modules)

I don't know what "non-bootcpu" has to do with anything.  What matters  
is what piece of code does the restoring, and if the cache flush  
properly happens then.

-Scott