From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-f197.google.com (mail-qt1-f197.google.com [209.85.160.197]) by kanga.kvack.org (Postfix) with ESMTP id 15A1B6B2065 for ; Tue, 20 Nov 2018 09:12:29 -0500 (EST) Received: by mail-qt1-f197.google.com with SMTP id n95so70239qte.16 for ; Tue, 20 Nov 2018 06:12:29 -0800 (PST) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id n127si2966876qkf.230.2018.11.20.06.12.28 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 20 Nov 2018 06:12:28 -0800 (PST) Date: Tue, 20 Nov 2018 22:12:21 +0800 From: Baoquan He Subject: Re: Memory hotplug softlock issue Message-ID: <20181120141221.GA7386@MiWiFi-R3L-srv> References: <20181119125121.GK22247@dhcp22.suse.cz> <20181119141016.GO22247@dhcp22.suse.cz> <20181119173312.GV22247@dhcp22.suse.cz> <20181119205907.GW22247@dhcp22.suse.cz> <20181120015644.GA5727@MiWiFi-R3L-srv> <3f1a82a8-f2aa-ac5e-e6a8-057256162321@suse.cz> <20181120135803.GA3369@MiWiFi-R3L-srv> <20181120140524.GI22247@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181120140524.GI22247@dhcp22.suse.cz> Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: Hugh Dickins , Vlastimil Babka , pifang@redhat.com, David Hildenbrand , linux-mm@kvack.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, aarcange@redhat.com, Mel Gorman On 11/20/18 at 03:05pm, Michal Hocko wrote: > > Yes, I applied Hugh's patch 8 hours ago, then our QE Ping operated on > > that machine, after many times of hot removing/adding, the endless > > looping during mirgrating is not seen any more. The test result for > > Hugh's patch is positive. I even suggested Ping increasing the memory > > pressure to "stress -m 250", it still succeeded to offline and remove. > > > > So I think this patch works to solve the issue. Thanks a lot for your > > help, all of you. > > This is a great news! Thanks for your swift feedback. I will go and try > to review Hugh's patch soon. Yeah. Thanks a lot for your help on debugging and narrowing down to position the cause of the issue, Michal, really appreciated! > > Meanwhile we found sometime onlining page may not add back all memory > > blocks on one memory board, then hot removing/adding them will cause > > kernel panic. I will investigate further and collect information, see if > > it's a kernel issue or udev issue. > > It would be great to get a report in a new email thread. Sure, will do after reproducing and inforamtion arranging. Thanks Baoquan