From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f69.google.com (mail-wm0-f69.google.com [74.125.82.69]) by kanga.kvack.org (Postfix) with ESMTP id 7AD146B0005 for ; Wed, 10 Aug 2016 13:59:52 -0400 (EDT) Received: by mail-wm0-f69.google.com with SMTP id l4so70116903wml.0 for ; Wed, 10 Aug 2016 10:59:52 -0700 (PDT) Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com. [148.163.158.5]) by mx.google.com with ESMTPS id mn4si40803251wjb.101.2016.08.10.10.59.50 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Aug 2016 10:59:51 -0700 (PDT) Received: from pps.filterd (m0098421.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.11/8.16.0.11) with SMTP id u7AHrqMh095336 for ; Wed, 10 Aug 2016 13:59:49 -0400 Received: from e18.ny.us.ibm.com (e18.ny.us.ibm.com [129.33.205.208]) by mx0a-001b2d01.pphosted.com with ESMTP id 24qm9r1n31-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 10 Aug 2016 13:59:49 -0400 Received: from localhost by e18.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 10 Aug 2016 13:59:48 -0400 Date: Wed, 10 Aug 2016 12:59:40 -0500 From: Reza Arbab Subject: Re: mm: Initialise per_cpu_nodestats for all online pgdats at boot References: <20160804092404.GI2799@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20160804092404.GI2799@techsingularity.net> Message-Id: <20160810175940.GA12039@arbab-laptop.austin.ibm.com> Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Andrew Morton , Paul Mackerras , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linuxppc-dev@ozlabs.org On Thu, Aug 04, 2016 at 10:24:04AM +0100, Mel Gorman wrote: >[ 1.713998] Unable to handle kernel paging request for data at address 0xff7a10000 >[ 1.714164] Faulting instruction address: 0xc000000000270cd0 >[ 1.714304] Oops: Kernel access of bad area, sig: 11 [#1] >[ 1.714414] SMP NR_CPUS=2048 NUMA PowerNV >[ 1.714530] Modules linked in: >[ 1.714647] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.7.0-kvm+ #118 >[ 1.714786] task: c000000ff0680010 task.stack: c000000ff0704000 >[ 1.714926] NIP: c000000000270cd0 LR: c000000000270ce8 CTR: 0000000000000000 >[ 1.715093] REGS: c000000ff0707900 TRAP: 0300 Not tainted (4.7.0-kvm+) >[ 1.715232] MSR: 9000000102009033 CR: 846b6824 XER: 20000000 >[ 1.715748] CFAR: c000000000008768 DAR: 0000000ff7a10000 DSISR: 42000000 SOFTE: 1 >GPR00: c000000000270d08 c000000ff0707b80 c0000000011fb200 0000000000000000 >GPR04: 0000000000000800 0000000000000000 0000000000000000 0000000000000000 >GPR08: ffffffffffffffff 0000000000000000 0000000ff7a10000 c00000000122aae0 >GPR12: c000000000a1e440 c00000000fb80000 c00000000000c188 0000000000000000 >GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 >GPR20: 0000000000000000 0000000000000000 0000000000000000 c000000000cecad0 >GPR24: c000000000d035b8 c000000000d6cd18 c000000000d6cd18 c000001fffa86300 >GPR28: 0000000000000000 c000001fffa96300 c000000001230034 c00000000122eb18 >[ 1.717484] NIP [c000000000270cd0] refresh_zone_stat_thresholds+0x80/0x240 >[ 1.717568] LR [c000000000270ce8] refresh_zone_stat_thresholds+0x98/0x240 >[ 1.717648] Call Trace: >[ 1.717687] [c000000ff0707b80] [c000000000270d08] refresh_zone_stat_thresholds+0xb8/0x240 (unreliable) I've been investigating node hotplug. That path is also going to require initialization of per_cpu_nodestats. This worked for me: diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 3894b65..41266dc 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -1219,6 +1219,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) /* init node's zones as empty zones, we don't have any present pages.*/ free_area_init_node(nid, zones_size, start_pfn, zholes_size); + pgdat->per_cpu_nodestats = alloc_percpu(struct per_cpu_nodestat); /* * The node we allocated has no zone fallback lists. For avoiding @@ -1249,6 +1250,7 @@ static pg_data_t __ref *hotadd_new_pgdat(int nid, u64 start) static void rollback_node_hotadd(int nid, pg_data_t *pgdat) { arch_refresh_nodedata(nid, NULL); + free_percpu(pgdat->per_cpu_nodestats); arch_free_nodedata(pgdat); return; } -- Reza Arbab -- 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