Re: [PATCH v6 09/10] mm/memory_hotplug: Drop local variables in shrink_zone_span()

Oscar Salvador
2020-02-04T09:26:23Z

On Sun, Oct 06, 2019 at 10:56:45AM +0200, David Hildenbrand wrote:
> Get rid of the unnecessary local variables.
>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> mm/memory_hotplug.c | 15 ++++++---------
> 1 file changed, 6 insertions(+), 9 deletions(-)
>
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 8dafa1ba8d9f..843481bd507d 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -374,14 +374,11 @@ static unsigned long find_biggest_section_pfn(int nid, struct zone *zone,
> static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
> unsigned long end_pfn)
> {
> - unsigned long zone_start_pfn = zone->zone_start_pfn;
> - unsigned long z = zone_end_pfn(zone); /* zone_end_pfn namespace clash */
> - unsigned long zone_end_pfn = z;
> unsigned long pfn;
> int nid = zone_to_nid(zone);

We could also remove the nid, right?
AFAICS, the nid is only used in find_{smallest/biggest}_section_pfn so we could
place there as well.

Anyway, nothing to nit-pick about:

Reviewed-by: Oscar Salvador <osalvador@suse.de>

>
> zone_span_writelock(zone);
> - if (zone_start_pfn = start_pfn) {
> + if (zone->zone_start_pfn = start_pfn) {
> /*
> * If the section is smallest section in the zone, it need
> * shrink zone->zone_start_pfn and zone->zone_spanned_pages.
> @@ -389,25 +386,25 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
> * for shrinking zone.
> */
> pfn = find_smallest_section_pfn(nid, zone, end_pfn,
> - zone_end_pfn);
> + zone_end_pfn(zone));
> if (pfn) {
> + zone->spanned_pages = zone_end_pfn(zone) - pfn;
> zone->zone_start_pfn = pfn;
> - zone->spanned_pages = zone_end_pfn - pfn;
> } else {
> zone->zone_start_pfn = 0;
> zone->spanned_pages = 0;
> }
> - } else if (zone_end_pfn = end_pfn) {
> + } else if (zone_end_pfn(zone) = end_pfn) {
> /*
> * If the section is biggest section in the zone, it need
> * shrink zone->spanned_pages.
> * In this case, we find second biggest valid mem_section for
> * shrinking zone.
> */
> - pfn = find_biggest_section_pfn(nid, zone, zone_start_pfn,
> + pfn = find_biggest_section_pfn(nid, zone, zone->zone_start_pfn,
> start_pfn);
> if (pfn)
> - zone->spanned_pages = pfn - zone_start_pfn + 1;
> + zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
> else {
> zone->zone_start_pfn = 0;
> zone->spanned_pages = 0;
> --
> 2.21.0
>

--
Oscar Salvador
SUSE L3