Hi jan
> -----Original Message-----
> From: Jan Beulich <jbeul...@suse.com>
> Sent: Tuesday, April 19, 2022 5:11 PM
> To: Penny Zheng <penny.zh...@arm.com>
> Cc: Wei Chen <wei.c...@arm.com>; Stefano Stabellini
> <sstabell...@kernel.org>; Julien Grall <jul...@xen.org>; Bertrand Marquis
> <bertrand.marq...@arm.com>; Volodymyr Babchuk
> <volodymyr_babc...@epam.com>; Andrew Cooper
> <andrew.coop...@citrix.com>; George Dunlap <george.dun...@citrix.com>;
> Wei Liu <w...@xen.org>; xen-devel@lists.xenproject.org
> Subject: Re: [PATCH v2 5/6] xen/arm: unpopulate memory when domain is
> static
>
> On 18.04.2022 14:22, Penny Zheng wrote:
> > --- a/xen/arch/arm/include/asm/mm.h
> > +++ b/xen/arch/arm/include/asm/mm.h
> > @@ -358,6 +358,23 @@ void clear_and_clean_page(struct page_info
> > *page);
> >
> > unsigned int arch_get_dma_bitsize(void);
> >
> > +/*
> > + * Put free pages on the resv page list after having taken them
> > + * off the "normal" page list, when pages from static memory */
> > +#ifdef CONFIG_STATIC_MEMORY
> > +#define arch_free_heap_page(d, pg) { \
> > + if ( (pg)->count_info & PGC_reserved ) \
> > + { \
> > + page_list_del(pg, page_to_list(d, pg)); \
> > + page_list_add_tail(pg, &(d)->resv_page_list); \
> > + (d)->resv_pages++; \
>
> There's no consumer of this counter, so I'd like to ask that it be introduced
> once a consumer appears.
>
> > + } \
> > + else \
> > + page_list_del(pg, page_to_list(d, pg)); \
>
> Is there a particular reason to have this page_list_del() twice, instead of
> just
> once ahead of the if()?
>
> > +}
>
> Also this entire construct want to be an expression, not a
> (compound) statement. And it probably would better evaluate its parameters
> just once.
>
#define arch_free_heap_page(d, pg) { \
page_list_del(pg, page_to_list(d, pg)); \
if ( (pg)->count_info & PGC_reserved ) \
page_list_add_tail(pg, &(d)->resv_page_list); \
}
I'm trying to refine the arch_free_heap_page() here, but I'm a bit confused
about to let it be an expression, not a compound statement. Do you mean that
you prefer to let the if-clause out of the arch_free_heap_page()?
> Jan
