The patch titled
Subject: mm/memory_hotplug: update comment regarding zone shuffling
has been added to the -mm tree. Its filename is
mm-memory_hotplug-update-comment-regarding-zone-shuffling.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplug-update-comment-regarding-zone-shuffling.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplug-update-comment-regarding-zone-shuffling.patch
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: 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.
Link: https://lkml.kernel.org/r/20201005121534.15649-6-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Cc: Alexander Duyck <alexander.h.duyck@xxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
Cc: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Scott Cheloha <cheloha@xxxxxxxxxxxxx>
Cc: Stephen Hemminger <sthemmin@xxxxxxxxxxxxx>
Cc: Wei Liu <wei.liu@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
--- a/mm/memory_hotplug.c~mm-memory_hotplug-update-comment-regarding-zone-shuffling
+++ a/mm/memory_hotplug.c
@@ -858,13 +858,10 @@ int __ref online_pages(unsigned long pfn
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);
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
mm-page_alloc-tweak-comments-in-has_unmovable_pages.patch
mm-page_isolation-exit-early-when-pageblock-is-isolated-in-set_migratetype_isolate.patch
mm-page_isolation-drop-warn_on_once-in-set_migratetype_isolate.patch
mm-page_isolation-cleanup-set_migratetype_isolate.patch
virtio-mem-dont-special-case-zone_movable.patch
mm-document-semantics-of-zone_movable.patch
mm-memory_hotplug-inline-__offline_pages-into-offline_pages.patch
mm-memory_hotplug-enforce-section-granularity-when-onlining-offlining.patch
mm-memory_hotplug-simplify-page-offlining.patch
mm-page_alloc-simplify-__offline_isolated_pages.patch
mm-memory_hotplug-drop-nr_isolate_pageblock-in-offline_pages.patch
mm-page_isolation-simplify-return-value-of-start_isolate_page_range.patch
mm-memory_hotplug-simplify-page-onlining.patch
mm-page_alloc-drop-stale-pageblock-comment-in-memmap_init_zone.patch
mm-pass-migratetype-into-memmap_init_zone-and-move_pfn_range_to_zone.patch
mm-memory_hotplug-mark-pageblocks-migrate_isolate-while-onlining-memory.patch
kernel-resource-make-release_mem_region_adjustable-never-fail.patch
kernel-resource-move-and-rename-ioresource_mem_driver_managed.patch
mm-memory_hotplug-guard-more-declarations-by-config_memory_hotplug.patch
mm-memory_hotplug-prepare-passing-flags-to-add_memory-and-friends.patch
mm-memory_hotplug-memhp_merge_resource-to-specify-merging-of-system-ram-resources.patch
virtio-mem-try-to-merge-system-ram-resources.patch
xen-balloon-try-to-merge-system-ram-resources.patch
hv_balloon-try-to-merge-system-ram-resources.patch
kernel-resource-make-iomem_resource-implicit-in-release_mem_region_adjustable.patch
mm-page_alloc-convert-report-flag-of-__free_one_page-to-a-proper-flag.patch
mm-page_alloc-place-pages-to-tail-in-__putback_isolated_page.patch
mm-page_alloc-move-pages-to-tail-in-move_to_free_list.patch
mm-page_alloc-place-pages-to-tail-in-__free_pages_core.patch
mm-memory_hotplug-update-comment-regarding-zone-shuffling.patch
