The patch titled
Subject: mm/migrate.c: split only transparent huge pages when allocation fails
has been removed from the -mm tree. Its filename was
mm-migrate-split-only-transparent-huge-pages-when-allocation-fails.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Subject: mm/migrate.c: split only transparent huge pages when allocation fails
split_huge_page_to_list() fails on HugeTLB pages. I was experimenting
with moving 32MB contig HugeTLB pages on arm64 (with a debug patch
applied) and hit the following stack trace when the kernel crashed.
[ 3732.462797] Call trace:
[ 3732.462835] split_huge_page_to_list+0x3b0/0x858
[ 3732.462913] migrate_pages+0x728/0xc20
[ 3732.462999] soft_offline_page+0x448/0x8b0
[ 3732.463097] __arm64_sys_madvise+0x724/0x850
[ 3732.463197] el0_svc_handler+0x74/0x110
[ 3732.463297] el0_svc+0x8/0xc
[ 3732.463347] Code: d1000400 f90b0e60 f2fbd5a2 a94982a1 (f9000420)
When unmap_and_move[_huge_page]() fails due to lack of memory, the
splitting should happen only for transparent huge pages not for HugeTLB
pages. PageTransHuge() returns true for both THP and HugeTLB pages.
Hence the conditonal check should test PagesHuge() flag to make sure that
given pages is not a HugeTLB one.
Link: http://lkml.kernel.org/r/1537798495-4996-1-git-send-email-anshuman.khandual@xxxxxxx
Fixes: 94723aafb9 ("mm: unclutter THP migration")
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Zi Yan <zi.yan@xxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/migrate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/migrate.c~mm-migrate-split-only-transparent-huge-pages-when-allocation-fails
+++ a/mm/migrate.c
@@ -1414,7 +1414,7 @@ retry:
* we encounter them after the rest of the list
* is processed.
*/
- if (PageTransHuge(page)) {
+ if (PageTransHuge(page) && !PageHuge(page)) {
lock_page(page);
rc = split_huge_page_to_list(page, from);
unlock_page(page);
_
Patches currently in -mm which might be from anshuman.khandual@xxxxxxx are
