On Fri 16-04-21 13:24:06, Oscar Salvador wrote:
> From: David Hildenbrand <da...@redhat.com>
> 
> Let's have a single place (inspired by adjust_managed_page_count()) where
> we adjust present pages.
> In contrast to adjust_managed_page_count(), only memory onlining/offlining
> is allowed to modify the number of present pages.
> 
> Signed-off-by: David Hildenbrand <da...@redhat.com>
> Signed-off-by: Oscar Salvador <osalva...@suse.de>
> Reviewed-by: Oscar Salvador <osalva...@suse.de>

Not sure self review counts ;)

Acked-by: Michal Hocko <mho...@suse.com>

Btw. I strongly suspect the resize lock is quite pointless here.
Something for a follow up patch.

> ---
>  mm/memory_hotplug.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 25e59d5dc13c..d05056b3c173 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -829,6 +829,16 @@ struct zone * zone_for_pfn_range(int online_type, int 
> nid, unsigned start_pfn,
>       return default_zone_for_pfn(nid, start_pfn, nr_pages);
>  }
>  
> +static void adjust_present_page_count(struct zone *zone, long nr_pages)
> +{
> +     unsigned long flags;
> +
> +     zone->present_pages += nr_pages;
> +     pgdat_resize_lock(zone->zone_pgdat, &flags);
> +     zone->zone_pgdat->node_present_pages += nr_pages;
> +     pgdat_resize_unlock(zone->zone_pgdat, &flags);
> +}
> +
>  int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
>                      int online_type, int nid)
>  {
> @@ -882,11 +892,7 @@ int __ref online_pages(unsigned long pfn, unsigned long 
> nr_pages,
>       }
>  
>       online_pages_range(pfn, nr_pages);
> -     zone->present_pages += nr_pages;
> -
> -     pgdat_resize_lock(zone->zone_pgdat, &flags);
> -     zone->zone_pgdat->node_present_pages += nr_pages;
> -     pgdat_resize_unlock(zone->zone_pgdat, &flags);
> +     adjust_present_page_count(zone, nr_pages);
>  
>       node_states_set_node(nid, &arg);
>       if (need_zonelists_rebuild)
> @@ -1701,11 +1707,7 @@ int __ref offline_pages(unsigned long start_pfn, 
> unsigned long nr_pages)
>  
>       /* removal success */
>       adjust_managed_page_count(pfn_to_page(start_pfn), -nr_pages);
> -     zone->present_pages -= nr_pages;
> -
> -     pgdat_resize_lock(zone->zone_pgdat, &flags);
> -     zone->zone_pgdat->node_present_pages -= nr_pages;
> -     pgdat_resize_unlock(zone->zone_pgdat, &flags);
> +     adjust_present_page_count(zone, -nr_pages);
>  
>       init_per_zone_wmark_min();
>  
> -- 
> 2.16.3

-- 
Michal Hocko
SUSE Labs

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