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mm/page_isolation: do not isolate the max order page

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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
Fixes: 3c605096d3 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Muchun Song 2020-12-14 19:12:27 -08:00 committed by Linus Torvalds
parent 8d87d07c92
commit 2484be0f88
1 changed files with 1 additions and 1 deletions
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2
mm/page_isolation.c
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@ -88,7 +88,7 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype)
*/
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);