The patch titled
Subject: mm/hugetlb: avoid soft lockup in set_max_huge_pages()
has been added to the -mm tree. Its filename is
mm-hugetlb-avoid-soft-lockup-in-set_max_huge_pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-hugetlb-avoid-soft-lockup-in-set_max_huge_pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-hugetlb-avoid-soft-lockup-in-set_max_huge_pages.patch
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------------------------------------------------------
From: Jia He <hejianet@xxxxxxxxx>
Subject: mm/hugetlb: avoid soft lockup in set_max_huge_pages()
In powerpc servers with large memory(32TB), we watched several soft
lockups for hugepage under stress tests.
The call traces are as follows:
1.
get_page_from_freelist+0x2d8/0xd50
__alloc_pages_nodemask+0x180/0xc20
alloc_fresh_huge_page+0xb0/0x190
set_max_huge_pages+0x164/0x3b0
2.
prep_new_huge_page+0x5c/0x100
alloc_fresh_huge_page+0xc8/0x190
set_max_huge_pages+0x164/0x3b0
This patch fixes such soft lockups. It is safe to call cond_resched()
there because it is out of spin_lock/unlock section.
Link: http://lkml.kernel.org/r/1469674442-14848-1-git-send-email-hejianet@xxxxxxxxx
Signed-off-by: Jia He <hejianet@xxxxxxxxx>
Reviewed-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Acked-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 4 ++++
1 file changed, 4 insertions(+)
diff -puN mm/hugetlb.c~mm-hugetlb-avoid-soft-lockup-in-set_max_huge_pages mm/hugetlb.c
--- a/mm/hugetlb.c~mm-hugetlb-avoid-soft-lockup-in-set_max_huge_pages
+++ a/mm/hugetlb.c
@@ -2216,6 +2216,10 @@ static unsigned long set_max_huge_pages(
* and reducing the surplus.
*/
spin_unlock(&hugetlb_lock);
+
+ /* yield cpu to avoid soft lockup */
+ cond_resched();
+
if (hstate_is_gigantic(h))
ret = alloc_fresh_gigantic_page(h, nodes_allowed);
else
_
Patches currently in -mm which might be from hejianet@xxxxxxxxx are
mm-hugetlb-avoid-soft-lockup-in-set_max_huge_pages.patch
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