Hi julien
> -----Original Message-----
> From: Julien Grall <jul...@xen.org>
> Sent: Wednesday, April 27, 2022 6:23 PM
> To: Penny Zheng <penny.zh...@arm.com>; xen-devel@lists.xenproject.org
> Cc: Wei Chen <wei.c...@arm.com>; Henry Wang <henry.w...@arm.com>;
> Stefano Stabellini <sstabell...@kernel.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>;
> Jan Beulich <jbeul...@suse.com>; Wei Liu <w...@xen.org>
> Subject: Re: [PATCH v3 5/6] xen/arm: unpopulate memory when domain is
> static
>
> Hi Penny,
>
> On 27/04/2022 11:19, Penny Zheng wrote:
> >>> +/*
> >>> + * 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) ({ \
> >>> + page_list_del(pg, page_to_list(d, pg)); \
> >>> + if ( (pg)->count_info & PGC_reserved ) \
> >>> + page_list_add_tail(pg, &(d)->resv_page_list); \
> >>> +})
> >>> +#endif
> >>
> >> I am a bit puzzled how this is meant to work.
> >>
> >> Looking at the code, arch_free_heap_page() will be called from
> >> free_domheap_pages(). If I am not mistaken, reserved pages are not
> >> considered as xen heap pages, so we would go in the else which will
> >> end up to call free_heap_pages().
> >>
> >> free_heap_pages() will end up to add the page in the heap allocator
> >> and corrupt the d->resv_page_list because there are only one link list.
> >>
> >> What did I miss?
> >>
> >
> > In my first commit "do not free reserved memory into heap", I've
> > changed the behavior for reserved pages in free_heap_pages()
> > + if ( pg->count_info & PGC_reserved )that
> > + /* Reserved page shall not go back to the heap. */
> > + return free_staticmem_pages(pg, 1UL << order, need_scrub);
> > +
>
> Hmmm... somehow this e-mail is neither in my inbox nor in the archives on
> lore.kernel.org.
>
Oh.... I just got email from tessian that they held my first commit, and needed
my
confirmation to send. So sorry about that!!!
I'll re-send my first commit ASAP.
> Cheers,
> --
> Julien Grall
