From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-001b2d01.pphosted.com (mx0b-001b2d01.pphosted.com [148.163.158.5]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3yd7X02MQLzDr5W for ; Fri, 17 Nov 2017 04:29:04 +1100 (AEDT) Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vAGHQ2pS014762 for ; Thu, 16 Nov 2017 12:28:59 -0500 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0b-001b2d01.pphosted.com with ESMTP id 2e9csc89b1-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Thu, 16 Nov 2017 12:28:59 -0500 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 16 Nov 2017 10:28:58 -0700 To: linuxppc-dev@lists.ozlabs.org Cc: Michael Bringmann , Nathan Fontenot , Michael Ellerman , John Allen , Tyrel Datwyler , Thomas Falcon In-Reply-To: From: Michael Bringmann Subject: [PATCH V7 3/3] hotplug/cpu: Fix crash with memoryless nodes Date: Thu, 16 Nov 2017 11:28:55 -0600 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Message-Id: <3445a368-d2d4-f908-5f0e-df7bbd659e07@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On powerpc systems with shared configurations of CPUs and memory and memoryless nodes at boot, an event ordering problem was observed on a SLES12 build platforms with the hot-add of CPUs to the memoryless nodes. * The most common error occurred when the memory SLAB driver attempted to reference the memoryless node to which a CPU was being added before the kernel had finished initializing all of the data structures for the CPU and exited 'device_online' under DLPAR/hot-add. Normally the memoryless node would be initialized through the call path device_online ... arch_update_cpu_topology ... find_cpu_nid ... try_online_node. This patch ensures that the powerpc node will be initialized as early as possible, even if it was memoryless and CPU-less at the point when we are trying to hot-add a new CPU to it. Signed-off-by: Michael Bringmann --- Changes in V7: -- Make function find_cpu_nid() externally visible/usable so that it may be used from hotplug-cpu.c --- arch/powerpc/mm/numa.c | 3 ++- arch/powerpc/platforms/pseries/hotplug-cpu.c | 3 +++ 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index 163f4cc..d6d4f7c 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c @@ -1310,7 +1310,7 @@ static long vphn_get_associativity(unsigned long cpu, return rc; } -static inline int find_cpu_nid(int cpu) +int find_cpu_nid(int cpu) { __be32 associativity[VPHN_ASSOC_BUFSIZE] = {0}; int new_nid; @@ -1343,6 +1343,7 @@ static inline int find_cpu_nid(int cpu) #endif } + printk(KERN_INFO "%s:%d cpu %d nid %d\n", __FUNCTION__, __LINE__, cpu, new_nid); return new_nid; } diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index a7d14aa7..df8c732 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -340,6 +340,8 @@ static void pseries_remove_processor(struct device_node *np) cpu_maps_update_done(); } +extern int find_cpu_nid(int cpu); + static int dlpar_online_cpu(struct device_node *dn) { int rc = 0; @@ -364,6 +366,7 @@ static int dlpar_online_cpu(struct device_node *dn) != CPU_STATE_OFFLINE); cpu_maps_update_done(); timed_topology_update(1); + find_cpu_nid(cpu); rc = device_online(get_cpu_device(cpu)); if (rc) goto out;