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 _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html