Re: [PATCH 5/5] mm, memory_hotplug: be more verbose for memory offline failures

Michal Hocko
2018-11-16T11:22:22Z

On Fri 16-11-18 11:47:01, osalvador wrote:
> On Fri, 2018-11-16 at 09:30 +0100, Michal Hocko wrote:
> > From: Michal Hocko <mhocko@suse.com>
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index a919ba5cb3c8..ec2c7916dc2d 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -7845,6 +7845,7 @@ bool has_unmovable_pages(struct zone *zone,
> > struct page *page, int count,
> > return false;
> > unmovable:
> > WARN_ON_ONCE(zone_idx(zone) == ZONE_MOVABLE);
> > + dump_page(pfn_to_page(pfn+iter), "unmovable page");
>
> Would not be enough to just do:
>
> dump_page(page, "unmovable page".
>
> Unless I am missing something, page should already have the
> right pfn?

What if pfn_valid_within fails? You could have a pointer to the previous
page.

>
> <---
> unsigned long check = pfn + iter;
> page = pfn_to_page(check);
> --->
>
> The rest looks good to me
>
> Reviewed-by: Oscar Salvador <osalvador@suse.de>

Thanks!

--
Michal Hocko
SUSE Labs