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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6266FEB64D8 for ; Wed, 21 Jun 2023 06:12:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230184AbjFUGMb (ORCPT ); Wed, 21 Jun 2023 02:12:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52514 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229463AbjFUGM2 (ORCPT ); Wed, 21 Jun 2023 02:12:28 -0400 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C76B819F; Tue, 20 Jun 2023 23:12:27 -0700 (PDT) Received: from pps.filterd (m0353728.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 35L6BUJW032265; Wed, 21 Jun 2023 06:12:10 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : in-reply-to : references : date : message-id : mime-version : content-type; s=pp1; bh=0y8PgUzfkSCBAdm8cjFgV95f1jibdMlZeJxArc3waNM=; b=k5/skO+SlqzX2Rfys4RabqTh1V5lphr8pJlTa2zHMbckXawt9NYY6PD47nlqt0Az8ju1 IUxGZB97p07440vgNJlo07Hroiqu875KTD1Ll+UILt7uMgJdAJHraczxuTIbixrjyRCy +98tdV6YC04z95XUKHDQRitaDs7YU/cmzYnAX/lvu8aaoDV5pJXJhE6wJlgCaYfWWvLu r0nyI3ETbRaGQyejkfq+UHKoD1+gn+w3sj4FIaJ2IKjKGIsSa98b68FCl/HFkZkjCTsB q//ouqf2vjy4KNF7dm30FQg4WDqoAed0lG5C+gbSCmx6BLFT5/joir3HsqpBebhznR+a Rg== Received: from ppma04fra.de.ibm.com (6a.4a.5195.ip4.static.sl-reverse.com [149.81.74.106]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3rbuj40hau-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 21 Jun 2023 06:12:10 +0000 Received: from pps.filterd (ppma04fra.de.ibm.com [127.0.0.1]) by ppma04fra.de.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 35L4utO3012008; Wed, 21 Jun 2023 06:07:07 GMT Received: from smtprelay06.fra02v.mail.ibm.com ([9.218.2.230]) by ppma04fra.de.ibm.com (PPS) with ESMTPS id 3r94f59x4j-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 21 Jun 2023 06:07:07 +0000 Received: from smtpav02.fra02v.mail.ibm.com (smtpav02.fra02v.mail.ibm.com [10.20.54.101]) by smtprelay06.fra02v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 35L674fm37159548 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 21 Jun 2023 06:07:04 GMT Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E83182004B; Wed, 21 Jun 2023 06:07:03 +0000 (GMT) Received: from smtpav02.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 9159220043; Wed, 21 Jun 2023 06:07:01 +0000 (GMT) Received: from tarunpc (unknown [9.199.157.25]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTPS; Wed, 21 Jun 2023 06:07:01 +0000 (GMT) From: Tarun Sahu To: Alison Schofield Cc: nvdimm@lists.linux.dev, linux-cxl@vger.kernel.org, linux-kernel@vger.kernel.org, dave.jiang@intel.com, dan.j.williams@intel.com, vishal.l.verma@intel.com, aneesh.kumar@linux.ibm.com, jaypatel@linux.ibm.com Subject: Re: [PATCH] dax/kmem: Pass valid argument to memory_group_register_static In-Reply-To: References: <20230620140332.30578-1-tsahu@linux.ibm.com> Date: Wed, 21 Jun 2023 11:36:59 +0530 Message-ID: <87cz1p1h8c.fsf@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-GUID: ZIRM5Sl2_gVfwJXkQomnEZVM3qu1T5_n X-Proofpoint-ORIG-GUID: ZIRM5Sl2_gVfwJXkQomnEZVM3qu1T5_n X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.254,Aquarius:18.0.957,Hydra:6.0.591,FMLib:17.11.176.26 definitions=2023-06-21_03,2023-06-16_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 clxscore=1011 malwarescore=0 priorityscore=1501 bulkscore=0 spamscore=0 impostorscore=0 suspectscore=0 mlxscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2305260000 definitions=main-2306210051 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Alison, Alison Schofield writes: > On Tue, Jun 20, 2023 at 07:33:32PM +0530, Tarun Sahu wrote: >> memory_group_register_static takes maximum number of pages as the argument >> while dev_dax_kmem_probe passes total_len (in bytes) as the argument. > > This sounds like a fix. An explanation of the impact and a fixes tag > may be needed. Also, wondering how you found it. > Yes, it is a fix, I found it during dry code walk-through. There is not any impact as such. As, memory_group_register_static just set the max_pages limit which is used in auto_movable_zone_for_pfn to determine the zone. which might cause these condition to behave differently, This will be true always so jump will happen to kernel_zone if (!auto_movable_can_online_movable(NUMA_NO_NODE, group, nr_pages)) goto kernel_zone; --- kernel_zone: return default_kernel_zone_for_pfn(nid, pfn, nr_pages); --- Here, In below, zone_intersects compare range will be larger as nr_pages will be higher (derived from total_len passed in dev_dax_kmem_probe). static struct zone *default_kernel_zone_for_pfn(int nid, unsigned long start_pfn, unsigned long nr_pages) { struct pglist_data *pgdat = NODE_DATA(nid); int zid; for (zid = 0; zid < ZONE_NORMAL; zid++) { struct zone *zone = &pgdat->node_zones[zid]; if (zone_intersects(zone, start_pfn, nr_pages)) return zone; } return &pgdat->node_zones[ZONE_NORMAL]; } In Mostly cases, ZONE_NORMAL will be returned. But there is no crash/panic issues involved here, only decision making on selecting zone is affected. > Alison > >> >> Signed-off-by: Tarun Sahu >> --- >> drivers/dax/kmem.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c >> index 7b36db6f1cbd..898ca9505754 100644 >> --- a/drivers/dax/kmem.c >> +++ b/drivers/dax/kmem.c >> @@ -99,7 +99,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) >> if (!data->res_name) >> goto err_res_name; >> >> - rc = memory_group_register_static(numa_node, total_len); >> + rc = memory_group_register_static(numa_node, PFN_UP(total_len)); >> if (rc < 0) >> goto err_reg_mgid; >> data->mgid = rc; >> -- >> 2.31.1 >>