From: Vlastimil Babka <vbabka@suse.cz>
Date: Sun, 25 Aug 2019 00:54:59 +0000 (-0700)
Subject: mm, page_owner: handle THP splits correctly
X-Git-Tag: v4.19.69~16
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=db67ac0316550a4f1b79a931750609be1f206b6c;p=thirdparty%2Fkernel%2Fstable.git

mm, page_owner: handle THP splits correctly

commit f7da677bc6e72033f0981b9d58b5c5d409fa641e upstream.

THP splitting path is missing the split_page_owner() call that
split_page() has.

As a result, split THP pages are wrongly reported in the page_owner file
as order-9 pages.  Furthermore when the former head page is freed, the
remaining former tail pages are not listed in the page_owner file at
all.  This patch fixes that by adding the split_page_owner() call into
__split_huge_page().

Link: http://lkml.kernel.org/r/20190820131828.22684-2-vbabka@suse.cz
Fixes: a9627bc5e34e ("mm/page_owner: introduce split_page_owner and replace manual handling")
Reported-by: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6fad1864ba03b..09ce8528bbdd9 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -33,6 +33,7 @@
 #include <linux/page_idle.h>
 #include <linux/shmem_fs.h>
 #include <linux/oom.h>
+#include <linux/page_owner.h>
 
 #include <asm/tlb.h>
 #include <asm/pgalloc.h>
@@ -2477,6 +2478,9 @@ static void __split_huge_page(struct page *page, struct list_head *list,
 	}
 
 	ClearPageCompound(head);
+
+	split_page_owner(head, HPAGE_PMD_ORDER);
+
 	/* See comment in __split_huge_page_tail() */
 	if (PageAnon(head)) {
 		/* Additional pin to radix tree of swap cache */