On Thu, Feb 06, 2020 at 01:39:12PM +0800, Baoquan He wrote:
>In commit 950b68d9178b ("mm/memory_hotplug: don't check for "all holes"
>in shrink_zone_span()"), the zone->zone_start_pfn/->spanned_pages
>resetting is moved into the if()/else if() branches, if the zone becomes
>empty. However the 2nd resetting code block may cause misunderstanding.
>
>So take the resetting codes out of the conditional checking and handling
>branches just as the old code does, the find_smallest_section_pfn()and
>find_biggest_section_pfn() searching have done the the same thing as
>the old for loop did, the logic is kept the same as the old code. This
>can remove the possible confusion.
>
>Signed-off-by: Baoquan He <bhe@xxxxxxxxxx>
Reviewed-by: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
>---
> mm/memory_hotplug.c | 14 ++++++--------
> 1 file changed, 6 insertions(+), 8 deletions(-)
>
>diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
>index 089b6c826a9e..475d0d68a32c 100644
>--- a/mm/memory_hotplug.c
>+++ b/mm/memory_hotplug.c
>@@ -398,7 +398,7 @@ 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 pfn;
>+ unsigned long pfn = zone->zone_start_pfn;
> int nid = zone_to_nid(zone);
>
> zone_span_writelock(zone);
>@@ -414,9 +414,6 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
> if (pfn) {
> zone->spanned_pages = zone_end_pfn(zone) - pfn;
> zone->zone_start_pfn = pfn;
>- } else {
>- zone->zone_start_pfn = 0;
>- zone->spanned_pages = 0;
> }
> } else if (zone_end_pfn(zone) == end_pfn) {
> /*
>@@ -429,10 +426,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
> start_pfn);
> if (pfn)
> zone->spanned_pages = pfn - zone->zone_start_pfn + 1;
>- else {
>- zone->zone_start_pfn = 0;
>- zone->spanned_pages = 0;
>- }
>+ }
>+
>+ if (!pfn) {
>+ zone->zone_start_pfn = 0;
>+ zone->spanned_pages = 0;
> }
> zone_span_writeunlock(zone);
> }
>--
>2.17.2
--
Wei Yang
Help you, Help me
