Re: [PATCH v6 08/10] mm/memory_hotplug: Don't check for "all holes" in shrink_zone_span()
From: Baoquan He <hidden>
Date: 2020-02-04 14:25:30
Also in:
linux-arm-kernel, linux-mm, linux-s390, linux-sh, lkml
On 10/06/19 at 10:56am, David Hildenbrand wrote:
quoted hunk ↗ jump to hunk
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. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Oscar Salvador <osalvador@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: David Hildenbrand <redacted> Cc: Pavel Tatashin <pasha.tatashin@soleen.com> Cc: Dan Williams <redacted> Cc: Wei Yang <redacted> Signed-off-by: David Hildenbrand <redacted> --- mm/memory_hotplug.c | 34 +++++++--------------------------- 1 file changed, 7 insertions(+), 27 deletions(-)diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index f294918f7211..8dafa1ba8d9f 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c@@ -393,6 +393,9 @@ 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) { /*@@ -405,34 +408,11 @@ static void shrink_zone_span(struct zone *zone, unsigned long start_pfn, start_pfn); if (pfn) zone->spanned_pages = pfn - zone_start_pfn + 1; + else { + zone->zone_start_pfn = 0; + zone->spanned_pages = 0;
Thinking in which case (zone_start_pfn != start_pfn) and it comes here.
+ }
}
-
- /*
- * 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 */
- zone->zone_start_pfn = 0;
- zone->spanned_pages = 0;
zone_span_writeunlock(zone);
}
--
2.21.0