RE: [PATCH 4/9] xen/arm: static memory initialization

[Penny Zheng <Penny.Zheng@xxxxxxx>]

Hi Julien

> -----Original Message-----
> From: Julien Grall <julien@xxxxxxx>
> Sent: Tuesday, July 6, 2021 5:10 PM
> To: Penny Zheng <Penny.Zheng@xxxxxxx>; xen-devel@xxxxxxxxxxxxxxxxxxxx;
> sstabellini@xxxxxxxxxx; jbeulich@xxxxxxxx
> Cc: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>; Wei Chen
> <Wei.Chen@xxxxxxx>
> Subject: Re: [PATCH 4/9] xen/arm: static memory initialization
> 
> 
> 
> On 05/07/2021 08:28, Penny Zheng wrote:
> > Hi Julien
> 
> Hi Penny,
> 
> >> -----Original Message-----
> >> From: Julien Grall <julien@xxxxxxx>
> >> Sent: Thursday, July 1, 2021 2:10 AM
> >> To: Penny Zheng <Penny.Zheng@xxxxxxx>;
> >> xen-devel@xxxxxxxxxxxxxxxxxxxx; sstabellini@xxxxxxxxxx;
> >> jbeulich@xxxxxxxx
> >> Cc: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>; Wei Chen
> >> <Wei.Chen@xxxxxxx>
> >> Subject: Re: [PATCH 4/9] xen/arm: static memory initialization
> >>
> >> Hi Penny,
> >>
> >> On 07/06/2021 03:43, Penny Zheng wrote:
> >>> This patch introduces static memory initialization, during system
> >>> RAM boot
> >> up.
> >>
> >> The word "RAM" looks spurious.
> >>
> >
> > Thx. I check the "spurious" in dictionary, it means fake? So I will leave
> "during system boot up"
> > here.
> 
> Yes, this reads better.
> 
> >>> 2. scrub the page in need synchronously.
> >>
> >> Can you explain why this is necessary?
> >>
> >
> > Since I'm borrowing the logic in free_heap_pages, I'm also trying to cover 
> > all
> the scenarios here like it does.
> > So I assume that free_staticmem_page will not only be used on 
> > initialization,
> but also when destroying/rebooting the domain.
> > On these cases, it is necessary to scrub the page, ig.
> 
> I wasn't asking about scrubbing specifically but instead why it is 
> synchronous.
> Sorry for the confusion.
> 

I've read asynchronous scrubbing in buddy allocator, pages that need a scrub 
are added to tail, 
and specific working thread is working on it, hmm, imo, I don't think it could 
be simply applied into static
memory. :/

So I put asynchronous scrubbing in #TODO.

> Cheers,
> 
> --
> Julien Grall

Cheers

--
Penny Zheng