From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756960AbcGZPoq (ORCPT ); Tue, 26 Jul 2016 11:44:46 -0400 Received: from mail-io0-f193.google.com ([209.85.223.193]:34349 "EHLO mail-io0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753165AbcGZPon (ORCPT ); Tue, 26 Jul 2016 11:44:43 -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: [RFC PATCH] mm/hugetlb: Avoid soft lockup in set_max_huge_pages() Date: Tue, 26 Jul 2016 23:44:28 +0800 Message-Id: <1469547868-9814-1-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 large memory(32TB) powerpc servers, we watched several soft lockup 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 lockup. I thouhgt it is safe to call cond_resched() because alloc_fresh_gigantic_page and alloc_fresh_huge_page are 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 --- mm/hugetlb.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index addfe4ac..d51759d 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1146,6 +1146,10 @@ static int alloc_fresh_gigantic_page(struct hstate *h, for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { page = alloc_fresh_gigantic_page_node(h, node); + + /* yield cpu */ + cond_resched(); + if (page) return 1; } @@ -1381,6 +1385,10 @@ static int alloc_fresh_huge_page(struct hstate *h, nodemask_t *nodes_allowed) for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { page = alloc_fresh_huge_page_node(h, node); + + /* yield cpu */ + cond_resched(); + if (page) { ret = 1; break; -- 2.5.0