[PATCH v6 08/10] mm/memory_hotplug: Don't check for "all holes" in shrink_zone_span()
From: David Hildenbrand <hidden>
Date: 2019-10-06 08:57:41
Also in:
linux-arm-kernel, linux-mm, linux-s390, linux-sh, lkml
Subsystem:
memory hot(un)plug, memory management, the rest · Maintainers:
David Hildenbrand, Oscar Salvador, Andrew Morton, Linus Torvalds
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; + } } - - /* - * 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