From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759250AbcG1CyZ (ORCPT ); Wed, 27 Jul 2016 22:54:25 -0400 Received: from mail-it0-f66.google.com ([209.85.214.66]:36184 "EHLO mail-it0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755892AbcG1CyR (ORCPT ); Wed, 27 Jul 2016 22:54:17 -0400 From: Jia He To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org, Jia He , Andrew Morton , Naoya Horiguchi , Mike Kravetz , "Kirill A. Shutemov" , Michal Hocko , Dave Hansen , Paul Gortmaker Subject: [PATCH V2] mm/hugetlb: Avoid soft lockup in set_max_huge_pages() Date: Thu, 28 Jul 2016 10:54:02 +0800 Message-Id: <1469674442-14848-1-git-send-email-hejianet@gmail.com> X-Mailer: git-send-email 2.5.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In powerpc servers with large memory(32TB), we watched several soft lockups for hugepage under stress tests. The call trace 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 is to fix such soft lockups. It is safe to call cond_resched() there because it is out of spin_lock/unlock section. Signed-off-by: Jia He Cc: Andrew Morton Cc: Naoya Horiguchi Cc: Mike Kravetz Cc: "Kirill A. Shutemov" Cc: Michal Hocko Cc: Dave Hansen Cc: Paul Gortmaker --- Changes in V2: move cond_resched to a common calling site in set_max_huge_pages mm/hugetlb.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index abc1c5f..9284280 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2216,6 +2216,10 @@ static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count, * 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 -- 2.5.0