+ mm-page_isolation-do-not-isolate-the-max-order-page.patch added to -mm tree

+ mm-page_isolation-do-not-isolate-the-max-order-page.patch added to -mm tree

[akpm]

The patch titled
     Subject: mm/page_isolation: do not isolate the max order page
has been added to the -mm tree.  Its filename is
     mm-page_isolation-do-not-isolate-the-max-order-page.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/mm-page_isolation-do-not-isolate-the-max-order-page.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_isolation-do-not-isolate-the-max-order-page.patch

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------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm/page_isolation: do not isolate the max order page

A max order page has no buddy page and never merges to another order.  So
isolating and then freeing it is pointless.

Link: https://lkml.kernel.org/r/20201202122114.75316-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_isolation.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/page_isolation.c~mm-page_isolation-do-not-isolate-the-max-order-page
+++ a/mm/page_isolation.c
@@ -88,7 +88,7 @@ static void unset_migratetype_isolate(st
 	 */
 	if (PageBuddy(page)) {
 		order = buddy_order(page);
-		if (order >= pageblock_order) {
+		if (order >= pageblock_order && order < MAX_ORDER - 1) {
 			pfn = page_to_pfn(page);
 			buddy_pfn = __find_buddy_pfn(pfn, order);
 			buddy = page + (buddy_pfn - pfn);
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-memcontrol-remove-unused-mod_memcg_obj_state.patch
mm-memcg-slab-fix-return-child-memcg-objcg-for-root-memcg.patch
mm-memcg-slab-fix-use-after-free-in-obj_cgroup_charge.patch
mm-memcg-slab-rename-_lruvec_slab_state-to-_lruvec_kmem_state.patch
mm-page_isolation-do-not-isolate-the-max-order-page.patch