mm/memory_hotplug: don't check for "all holes" in shrink_zone_span() (950b68d9) · Commits · 戴 / test

If we have holes, the holes will automatically get detected and removed once we remove the next bigger/smaller section. The extra checks can go. Link: http://lkml.kernel.org/r/20191006085646.5768-9-david@redhat.com Signed-off-by:

David Hildenbrand <david@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Pankaj Gupta <pagupta@redhat.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug.c

+7 −27

Original line number	Diff line number	Diff line
		@@ -411,6 +411,9 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
		if (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) {
		/*
		@@ -423,34 +426,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn,
		start_pfn);
		if (pfn)
		zone->spanned_pages = pfn - zone_start_pfn + 1;
		}

		/*
		* The section is not biggest or smallest mem_section in the zone, it
		* only creates a hole in the zone. So in this case, we need not
		* change the zone. But perhaps, the zone has only hole data. Thus
		* it check the zone has only hole or not.
		*/
		pfn = zone_start_pfn;
		for (; pfn < zone_end_pfn; pfn += PAGES_PER_SUBSECTION) {
		if (unlikely(!pfn_to_online_page(pfn)))
		continue;

		if (page_zone(pfn_to_page(pfn)) != zone)
		continue;

		/* Skip range to be removed */
		if (pfn >= start_pfn && pfn < end_pfn)
		continue;

		/* If we find valid section, we have nothing to do */
		zone_span_writeunlock(zone);
		return;
		}

		/* The zone has no valid section */
		else {
		zone->zone_start_pfn = 0;
		zone->spanned_pages = 0;
		}
		}
		zone_span_writeunlock(zone);
		}

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