Hi Julien

> -----Original Message-----
> From: Julien Grall <[email protected]>
> Sent: Tuesday, June 7, 2022 5:20 PM
> To: Penny Zheng <[email protected]>; [email protected]
> Cc: Wei Chen <[email protected]>; Stefano Stabellini
> <[email protected]>; Bertrand Marquis <[email protected]>;
> Volodymyr Babchuk <[email protected]>; Andrew Cooper
> <[email protected]>; George Dunlap <[email protected]>;
> Jan Beulich <[email protected]>; Wei Liu <[email protected]>
> Subject: Re: [PATCH v6 7/9] xen/arm: unpopulate memory when domain is
> static
> 
> Hi Penny,
> 
> On 07/06/2022 08:30, Penny Zheng wrote:
> > Today when a domain unpopulates the memory on runtime, they will
> > always hand the memory back to the heap allocator. And it will be a
> > problem if domain is static.
> >
> > Pages as guest RAM for static domain shall be reserved to only this
> > domain and not be used for any other purposes, so they shall never go
> > back to heap allocator.
> >
> > This commit puts reserved pages on the new list resv_page_list only
> > after having taken them off the "normal" list, when the last ref dropped.
> >
> > Signed-off-by: Penny Zheng <[email protected]>
> > Acked-by: Jan Beulich <[email protected]>
> > ---
> > v6 changes:
> > - refine in-code comment
> > - move PGC_static !CONFIG_STATIC_MEMORY definition to common header
> 
> I don't understand why this change is necessary for this patch. AFAICT, all 
> the
> users of PGC_static will be protected by #ifdef CONFIG_STATIC_MEMORY and
> therefore PGC_static should always be defined.
> 

True, I notice that arch_free_heap_page has already been guarded with
#ifdef CONFIG_STATIC_MEMORY. I'll revert the change.

> Cheers,
> 
> --
> Julien Grall

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