From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf0-f72.google.com (mail-lf0-f72.google.com [209.85.215.72]) by kanga.kvack.org (Postfix) with ESMTP id 6F33E6B025F for ; Thu, 28 Jul 2016 03:09:03 -0400 (EDT) Received: by mail-lf0-f72.google.com with SMTP id p85so10313101lfg.3 for ; Thu, 28 Jul 2016 00:09:03 -0700 (PDT) Received: from mail-wm0-f66.google.com (mail-wm0-f66.google.com. [74.125.82.66]) by mx.google.com with ESMTPS id bs1si11512880wjc.28.2016.07.28.00.09.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 28 Jul 2016 00:09:02 -0700 (PDT) Received: by mail-wm0-f66.google.com with SMTP id q128so9723538wma.1 for ; Thu, 28 Jul 2016 00:09:01 -0700 (PDT) Date: Thu, 28 Jul 2016 09:09:00 +0200 From: Michal Hocko Subject: Re: [PATCH V2] mm/hugetlb: Avoid soft lockup in set_max_huge_pages() Message-ID: <20160728070900.GA31860@dhcp22.suse.cz> References: <1469674442-14848-1-git-send-email-hejianet@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1469674442-14848-1-git-send-email-hejianet@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Jia He Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Naoya Horiguchi , Mike Kravetz , "Kirill A. Shutemov" , Dave Hansen , Paul Gortmaker On Thu 28-07-16 10:54:02, Jia He wrote: > 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 Acked-by: Michal Hocko > > --- > 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 > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: email@kvack.org -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org