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authorDavid Hildenbrand <david@redhat.com>2020-10-15 20:09:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-10-16 11:11:18 -0700
commitb86c5fc4e71a23e284b7cdfb757fb76534ab4119 (patch)
tree2ee36b5185cffe1d0b4a8b044be9c6ea1546e1e6
parent7fef431be9c9ac255838a9578331567b9dba4477 (diff)
mm/memory_hotplug: update comment regarding zone shuffling
As we no longer shuffle via generic_online_page() and when undoing isolation, we can simplify the comment. We now effectively shuffle only once (properly) when onlining new memory. Signed-off-by: David Hildenbrand <david@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Wei Yang <richard.weiyang@linux.alibaba.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Wei Yang <richard.weiyang@linux.alibaba.com> Cc: Oscar Salvador <osalvador@suse.de> Cc: Mike Rapoport <rppt@kernel.org> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Cc: Haiyang Zhang <haiyangz@microsoft.com> Cc: "K. Y. Srinivasan" <kys@microsoft.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Scott Cheloha <cheloha@linux.ibm.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: Wei Liu <wei.liu@kernel.org> Link: https://lkml.kernel.org/r/20201005121534.15649-6-david@redhat.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/memory_hotplug.c11
1 files changed, 4 insertions, 7 deletions
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index d397af38f9ce..6f203574ca1d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -858,13 +858,10 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages,
undo_isolate_page_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE);
/*
- * When exposing larger, physically contiguous memory areas to the
- * buddy, shuffling in the buddy (when freeing onlined pages, putting
- * them either to the head or the tail of the freelist) is only helpful
- * for maintaining the shuffle, but not for creating the initial
- * shuffle. Shuffle the whole zone to make sure the just onlined pages
- * are properly distributed across the whole freelist. Make sure to
- * shuffle once pageblocks are no longer isolated.
+ * Freshly onlined pages aren't shuffled (e.g., all pages are placed to
+ * the tail of the freelist when undoing isolation). Shuffle the whole
+ * zone to make sure the just onlined pages are properly distributed
+ * across the whole freelist - to create an initial shuffle.
*/
shuffle_zone(zone);