From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, NICE_REPLY_A,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 66057C433E2 for ; Tue, 15 Sep 2020 07:27:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CC922080C for ; Tue, 15 Sep 2020 07:27:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="oJ5M7IIN" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726320AbgIOH05 (ORCPT ); Tue, 15 Sep 2020 03:26:57 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:62476 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726252AbgIOHZF (ORCPT ); Tue, 15 Sep 2020 03:25:05 -0400 Received: from pps.filterd (m0098409.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08F76t66068686; Tue, 15 Sep 2020 03:24:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=subject : to : cc : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=pp1; bh=lIBF0yIZ/euhPJ4mHyoWSctgnR1mo++/vKvP8La0i+c=; b=oJ5M7IINZhbynnZEaZmnSftJUOvFg9/kCZsVnCNJAeG6xZ6hIK9U59AUFV+wPG/5k1NM jeFNj2w0VeTL3gjKNRCJ3b8hIRd0Ec9SB7Uuoy+TNhR/CmX9uIEe57fV5sCNvnWfXfuf jqsfxy7raCFnILrydLgkj21zRd8wrxRN5jZrZcxOHtmyc1c+Qm6fDqFsjpaFEk36V7kl Mqp7TOy7Xlv4IpcskBMB94j2lfOXN7zEDUQBXz8hLdmKIHVb/4zwhYpubrxqSBAnKKVF Msx8NQNpRmbqZ9bTM7tA5q7GQPcHemlQn3W2bGVkq0jt95oo30Xqajz/WUY9dJRIo9JW GA== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com with ESMTP id 33jqawatby-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Sep 2020 03:24:52 -0400 Received: from m0098409.ppops.net (m0098409.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.36/8.16.0.36) with SMTP id 08F78QBD072884; Tue, 15 Sep 2020 03:24:52 -0400 Received: from ppma05fra.de.ibm.com (6c.4a.5195.ip4.static.sl-reverse.com [149.81.74.108]) by mx0a-001b2d01.pphosted.com with ESMTP id 33jqawatb1-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Sep 2020 03:24:52 -0400 Received: from pps.filterd (ppma05fra.de.ibm.com [127.0.0.1]) by ppma05fra.de.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 08F7Mue0026200; Tue, 15 Sep 2020 07:24:49 GMT Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by ppma05fra.de.ibm.com with ESMTP id 33gny81prs-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Tue, 15 Sep 2020 07:24:49 +0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 08F7Ok4518809314 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 15 Sep 2020 07:24:46 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6A45752050; Tue, 15 Sep 2020 07:24:46 +0000 (GMT) Received: from pomme.local (unknown [9.145.72.89]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 789AF52052; Tue, 15 Sep 2020 07:24:45 +0000 (GMT) Subject: Re: [PATCH v2 3/3] mm: don't panic when links can't be created in sysfs To: David Hildenbrand , akpm@linux-foundation.org, Oscar Salvador , mhocko@kernel.org, Greg Kroah-Hartman Cc: linux-mm@kvack.org, "Rafael J . Wysocki" , nathanl@linux.ibm.com, cheloha@linux.ibm.com, Tony Luck , Fenghua Yu , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Michal Hocko References: <20200914165042.96218-1-ldufour@linux.ibm.com> <20200914165042.96218-4-ldufour@linux.ibm.com> From: Laurent Dufour Message-ID: <77a61ee9-0fec-f812-3999-8742bfcf7943@linux.ibm.com> Date: Tue, 15 Sep 2020 09:24:45 +0200 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-15_04:2020-09-15,2020-09-15 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 bulkscore=0 malwarescore=0 priorityscore=1501 clxscore=1015 mlxlogscore=999 spamscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 phishscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009150059 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Le 15/09/2020 à 09:23, David Hildenbrand a écrit : > On 14.09.20 18:50, Laurent Dufour wrote: >> At boot time, or when doing memory hot-add operations, if the links in >> sysfs can't be created, the system is still able to run, so just report the >> error in the kernel log rather than BUG_ON and potentially make system >> unusable because the callpath can be called with locks held. >> >> Since the number of memory blocks managed could be high, the messages are >> rate limited. >> >> As a consequence, link_mem_sections() has no status to report anymore. >> >> Signed-off-by: Laurent Dufour >> Acked-by: Michal Hocko >> Cc: David Hildenbrand >> Cc: Greg Kroah-Hartman >> --- >> drivers/base/node.c | 33 +++++++++++++++++++++------------ >> include/linux/node.h | 16 +++++++--------- >> mm/memory_hotplug.c | 5 ++--- >> 3 files changed, 30 insertions(+), 24 deletions(-) >> >> diff --git a/drivers/base/node.c b/drivers/base/node.c >> index 01ee73c9d675..249b2ba6dc81 100644 >> --- a/drivers/base/node.c >> +++ b/drivers/base/node.c >> @@ -761,8 +761,8 @@ static int __ref get_nid_for_pfn(unsigned long pfn) >> return pfn_to_nid(pfn); >> } >> >> -static int do_register_memory_block_under_node(int nid, >> - struct memory_block *mem_blk) >> +static void do_register_memory_block_under_node(int nid, >> + struct memory_block *mem_blk) >> { >> int ret; >> >> @@ -775,12 +775,19 @@ static int do_register_memory_block_under_node(int nid, >> ret = sysfs_create_link_nowarn(&node_devices[nid]->dev.kobj, >> &mem_blk->dev.kobj, >> kobject_name(&mem_blk->dev.kobj)); >> - if (ret) >> - return ret; >> + if (ret && ret != -EEXIST) >> + dev_err_ratelimited(&node_devices[nid]->dev, >> + "can't create link to %s in sysfs (%d)\n", >> + kobject_name(&mem_blk->dev.kobj), ret); >> >> - return sysfs_create_link_nowarn(&mem_blk->dev.kobj, >> + ret = sysfs_create_link_nowarn(&mem_blk->dev.kobj, >> &node_devices[nid]->dev.kobj, >> kobject_name(&node_devices[nid]->dev.kobj)); >> + if (ret && ret != -EEXIST) >> + dev_err_ratelimited(&mem_blk->dev, >> + "can't create link to %s in sysfs (%d)\n", >> + kobject_name(&node_devices[nid]->dev.kobj), >> + ret); >> } >> >> /* register memory section under specified node if it spans that node */ >> @@ -817,7 +824,8 @@ static int register_mem_block_under_node_early(struct memory_block *mem_blk, >> continue; >> >> /* The memory block is registered to the first matching node */ >> - return do_register_memory_block_under_node(nid, mem_blk); >> + do_register_memory_block_under_node(nid, mem_blk); >> + return 0; >> } >> /* mem section does not span the specified node */ >> return 0; >> @@ -832,7 +840,8 @@ static int register_mem_block_under_node_hotplug(struct memory_block *mem_blk, >> { >> int nid = *(int *)arg; >> >> - return do_register_memory_block_under_node(nid, mem_blk); >> + do_register_memory_block_under_node(nid, mem_blk); >> + return 0; >> } >> >> /* >> @@ -850,8 +859,8 @@ void unregister_memory_block_under_nodes(struct memory_block *mem_blk) >> kobject_name(&node_devices[mem_blk->nid]->dev.kobj)); >> } >> >> -int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn, >> - enum meminit_context context) >> +void link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn, >> + enum meminit_context context) >> { >> walk_memory_blocks_func_t func; >> >> @@ -860,9 +869,9 @@ int link_mem_sections(int nid, unsigned long start_pfn, unsigned long end_pfn, >> else >> func = register_mem_block_under_node_early; >> >> - return walk_memory_blocks(PFN_PHYS(start_pfn), >> - PFN_PHYS(end_pfn - start_pfn), (void *)&nid, >> - func); >> + walk_memory_blocks(PFN_PHYS(start_pfn), PFN_PHYS(end_pfn - start_pfn), >> + (void *)&nid, func); >> + return; >> } >> >> #ifdef CONFIG_HUGETLBFS >> diff --git a/include/linux/node.h b/include/linux/node.h >> index 014ba3ab2efd..8e5a29897936 100644 >> --- a/include/linux/node.h >> +++ b/include/linux/node.h >> @@ -99,15 +99,14 @@ extern struct node *node_devices[]; >> typedef void (*node_registration_func_t)(struct node *); >> >> #if defined(CONFIG_MEMORY_HOTPLUG_SPARSE) && defined(CONFIG_NUMA) >> -int link_mem_sections(int nid, unsigned long start_pfn, >> - unsigned long end_pfn, >> - enum meminit_context context); >> +void link_mem_sections(int nid, unsigned long start_pfn, >> + unsigned long end_pfn, >> + enum meminit_context context); >> #else >> -static inline int link_mem_sections(int nid, unsigned long start_pfn, >> - unsigned long end_pfn, >> - enum meminit_context context) >> +static inline void link_mem_sections(int nid, unsigned long start_pfn, >> + unsigned long end_pfn, >> + enum meminit_context context) >> { >> - return 0; >> } >> #endif >> >> @@ -130,8 +129,7 @@ static inline int register_one_node(int nid) >> if (error) >> return error; >> /* link memory sections under this node */ >> - error = link_mem_sections(nid, start_pfn, end_pfn, >> - MEMINIT_EARLY); >> + link_mem_sections(nid, start_pfn, end_pfn, MEMINIT_EARLY); >> } >> >> return error; >> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c >> index 03df20078827..01e01a530d38 100644 >> --- a/mm/memory_hotplug.c >> +++ b/mm/memory_hotplug.c >> @@ -1080,9 +1080,8 @@ int __ref add_memory_resource(int nid, struct resource *res) >> } >> >> /* link memory sections under this node.*/ >> - ret = link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1), >> - MEMINIT_HOTPLUG); >> - BUG_ON(ret); >> + link_mem_sections(nid, PFN_DOWN(start), PFN_UP(start + size - 1), >> + MEMINIT_HOTPLUG); >> >> /* create new memmap entry */ >> if (!strcmp(res->name, "System RAM")) >> > > I just remember that I still have some cleanup patches lying around that > rework the whole node onlining on the add_memory() path, being able to > fail in a nice way rather than ignoring errors. Anyhow, this is good > enough for now > > Acked-by: David Hildenbrand > Thanks David.