From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl1-f197.google.com (mail-pl1-f197.google.com [209.85.214.197]) by kanga.kvack.org (Postfix) with ESMTP id 8580E6B0572 for ; Wed, 7 Nov 2018 17:04:18 -0500 (EST) Received: by mail-pl1-f197.google.com with SMTP id g15-v6so10490127plq.4 for ; Wed, 07 Nov 2018 14:04:18 -0800 (PST) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id e92-v6si1939912pld.45.2018.11.07.14.04.16 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Nov 2018 14:04:17 -0800 (PST) Date: Wed, 7 Nov 2018 14:04:13 -0800 From: Andrew Morton Subject: Re: [RFC PATCH 4/5] mm, memory_hotplug: print reason for the offlining failure Message-Id: <20181107140413.2c0061e440123be76bf419bf@linux-foundation.org> In-Reply-To: <20181107101830.17405-5-mhocko@kernel.org> References: <20181107101830.17405-1-mhocko@kernel.org> <20181107101830.17405-5-mhocko@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, Oscar Salvador , Baoquan He , LKML , Michal Hocko On Wed, 7 Nov 2018 11:18:29 +0100 Michal Hocko wrote: > From: Michal Hocko > > The memory offlining failure reporting is inconsistent and insufficient. > Some error paths simply do not report the failure to the log at all. > When we do report there are no details about the reason of the failure > and there are several of them which makes memory offlining failures > hard to debug. > > Make sure that the > memory offlining [mem %#010llx-%#010llx] failed > message is printed for all failures and also provide a short textual > reason for the failure e.g. > > [ 1984.506184] rac1 kernel: memory offlining [mem 0x82600000000-0x8267fffffff] failed due to signal backoff > > this tells us that the offlining has failed because of a signal pending > aka user intervention. > > ... Some of these messages will come out looking a bit odd. > @@ -1573,7 +1576,8 @@ static int __ref __offline_pages(unsigned long start_pfn, > MIGRATE_MOVABLE, true); > if (ret) { > mem_hotplug_done(); > - return ret; > + reason = "failed to isolate range"; "memory offlining [mem ...] failed due to failed to isolate range" > + goto failed_removal > } > > arg.start_pfn = start_pfn; > @@ -1582,15 +1586,19 @@ static int __ref __offline_pages(unsigned long start_pfn, > > ret = memory_notify(MEM_GOING_OFFLINE, &arg); > ret = notifier_to_errno(ret); > - if (ret) > - goto failed_removal; > + if (ret) { > + reason = "notifiers failure"; "memory offlining [mem ...] failed due to notifiers failure" > @@ -1607,8 +1615,10 @@ static int __ref __offline_pages(unsigned long start_pfn, > * actually in order to make hugetlbfs's object counting consistent. > */ > ret = dissolve_free_huge_pages(start_pfn, end_pfn); > - if (ret) > - goto failed_removal; > + if (ret) { > + reason = "fails to disolve hugetlb pages"; "memory offlining [mem ...] failed due to fails to disolve hugetlb pages" Fix: --- a/mm/memory_hotplug.c~mm-memory_hotplug-print-reason-for-the-offlining-failure-fix +++ a/mm/memory_hotplug.c @@ -1576,7 +1576,7 @@ static int __ref __offline_pages(unsigne MIGRATE_MOVABLE, true); if (ret) { mem_hotplug_done(); - reason = "failed to isolate range"; + reason = "failure to isolate range"; goto failed_removal } @@ -1587,7 +1587,7 @@ static int __ref __offline_pages(unsigne ret = memory_notify(MEM_GOING_OFFLINE, &arg); ret = notifier_to_errno(ret); if (ret) { - reason = "notifiers failure"; + reason = "notifier failure"; goto failed_removal_isolated; } @@ -1616,7 +1616,7 @@ repeat: */ ret = dissolve_free_huge_pages(start_pfn, end_pfn); if (ret) { - reason = "fails to disolve hugetlb pages"; + reason = "failure to dissolve huge pages"; goto failed_removal_isolated; } /* check again */ _