linux-kernel - [PATCH V4 1/2] powerpc/numa: Update CPU topology when VPHN enabled

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Date:   Fri, 26 May 2017 16:29:45 -0500
From:   Michael Bringmann <mwb@...ux.vnet.ibm.com>
To:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Cc:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>,
        Reza Arbab <arbab@...ux.vnet.ibm.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Bharata B Rao <bharata@...ux.vnet.ibm.com>,
        Balbir Singh <bsingharora@...il.com>,
        Michael Bringmann <mwb@...ux.vnet.ibm.com>,
        Shailendra Singh <shailendras@...dia.com>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Nathan Fontenot <nfont@...ux.vnet.ibm.com>,
        Andrew Donnellan <andrew.donnellan@....ibm.com>,
        John Allen <jallen@...ux.vnet.ibm.com>,
        Tyrel Datwyler <tyreld@...ux.vnet.ibm.com>,
        Sahil Mehta <sahilmehta17@...il.com>,
        Rashmica Gupta <rashmicy@...il.com>,
        Ingo Molnar <mingo@...nel.org>
Subject: [PATCH V4 1/2] powerpc/numa: Update CPU topology when VPHN enabled


powerpc/numa: Correct the currently broken capability to set the
topology for shared CPUs in LPARs.  At boot time for shared CPU
lpars, the topology for each shared CPU is set to node zero, however,
this is now updated correctly using the Virtual Processor Home Node
(VPHN) capabilities information provided by the pHyp. The VPHN handling
in Linux is disabled, if PRRN handling is present.

Signed-off-by: Michael Bringmann <mwb@...ux.vnet.ibm.com>
---
Changes in V4:
 -- Fix conditional compile bug.
---
 arch/powerpc/mm/numa.c                 |   19 ++++++++++++++++++-
 arch/powerpc/platforms/pseries/dlpar.c |    2 ++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 371792e..afcee3f 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -29,6 +29,7 @@
 #include <linux/seq_file.h>
 #include <linux/uaccess.h>
 #include <linux/slab.h>
+#include <linux/sched.h>
 #include <asm/cputhreads.h>
 #include <asm/sparsemem.h>
 #include <asm/prom.h>
@@ -1153,6 +1154,8 @@ struct topology_update_data {
 static int vphn_enabled;
 static int prrn_enabled;
 static void reset_topology_timer(void);
+static int topology_inited;
+static int topology_update_needed;
 
 /*
  * Store the current values of the associativity change counters in the
@@ -1321,8 +1324,11 @@ int arch_update_cpu_topology(void)
 	struct device *dev;
 	int weight, new_nid, i = 0;
 
-	if (!prrn_enabled && !vphn_enabled)
+	if (!prrn_enabled && !vphn_enabled) {
+		if (!topology_inited)
+			topology_update_needed = 1;
 		return 0;
+	}
 
 	weight = cpumask_weight(&cpu_associativity_changes_mask);
 	if (!weight)
@@ -1361,6 +1367,8 @@ int arch_update_cpu_topology(void)
 			cpumask_andnot(&cpu_associativity_changes_mask,
 					&cpu_associativity_changes_mask,
 					cpu_sibling_mask(cpu));
+			pr_info("Assoc chg gives same node %d for cpu%d\n",
+					new_nid, cpu);
 			cpu = cpu_last_thread_sibling(cpu);
 			continue;
 		}
@@ -1377,6 +1385,9 @@ int arch_update_cpu_topology(void)
 		cpu = cpu_last_thread_sibling(cpu);
 	}
 
+	if (i)
+		updates[i-1].next = NULL;
+
 	pr_debug("Topology update for the following CPUs:\n");
 	if (cpumask_weight(&updated_cpus)) {
 		for (ud = &updates[0]; ud; ud = ud->next) {
@@ -1423,6 +1434,7 @@ int arch_update_cpu_topology(void)
 
 out:
 	kfree(updates);
+	topology_update_needed = 0;
 	return changed;
 }
 
@@ -1600,6 +1612,11 @@ static int topology_update_init(void)
 	if (!proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops))
 		return -ENOMEM;
 
+	topology_inited = 1;
+	if (topology_update_needed)
+		bitmap_fill(cpumask_bits(&cpu_associativity_changes_mask),
+					nr_cpumask_bits);
+
 	return 0;
 }
 device_initcall(topology_update_init);
diff --git a/arch/powerpc/platforms/pseries/dlpar.c b/arch/powerpc/platforms/pseries/dlpar.c
index bda18d8..5106263 100644
--- a/arch/powerpc/platforms/pseries/dlpar.c
+++ b/arch/powerpc/platforms/pseries/dlpar.c
@@ -592,6 +592,8 @@ static ssize_t dlpar_show(struct class *class, struct class_attribute *attr,
 
 static int __init pseries_dlpar_init(void)
 {
+	arch_update_cpu_topology();
+
 	pseries_hp_wq = alloc_workqueue("pseries hotplug workqueue",
 					WQ_UNBOUND, 1);
 	return sysfs_create_file(kernel_kobj, &class_attr_dlpar.attr);