Re: [PATCH V13 1/4] powerpc/vphn: Update CPU topology when VPHN enabled
From: Nathan Fontenot <hidden>
Date: 2017-09-06 14:24:07
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On 09/01/2017 10:48 AM, Michael Bringmann wrote:
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powerpc/vphn: On Power systems with shared configurations of CPUs and memory, there are some issues with the association of additional CPUs and memory to nodes when hot-adding resources. This patch corrects the currently broken capability to set the topology for shared CPUs in LPARs. At boot time for shared CPU lpars, the topology for each CPU was being set to node zero. Now when numa_update_cpu_topology() is called appropriately, the Virtual Processor Home Node (VPHN) capabilities information provided by the pHyp allows the appropriate node in the shared configuration to be selected for the CPU. Signed-off-by: Michael Bringmann <redacted> --- Changes in V13: -- Split patch for improved review --- arch/powerpc/mm/numa.c | 31 ++++++++++++++++++++++++++++--- 1 file changed, 28 insertions(+), 3 deletions(-)diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c index b95c584..312f6ee 100644 --- a/arch/powerpc/mm/numa.c +++ b/arch/powerpc/mm/numa.c@@ -1153,6 +1153,8 @@ 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@@ -1246,6 +1248,11 @@ static long vphn_get_associativity(unsigned long cpu, "hcall_vphn() experienced a hardware fault " "preventing VPHN. Disabling polling...\n"); stop_topology_update(); + break; + case H_SUCCESS: + dbg("VPHN hcall succeeded. Reset polling...\n"); + timed_topology_update(0); + break; } return rc;@@ -1323,8 +1330,11 @@ int numa_update_cpu_topology(bool cpus_locked) 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)@@ -1363,6 +1373,8 @@ int numa_update_cpu_topology(bool cpus_locked) 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);
As mentioned previously, this should either be removed or changed to a debug statement.
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cpu = cpu_last_thread_sibling(cpu); continue; }@@ -1433,6 +1445,7 @@ int numa_update_cpu_topology(bool cpus_locked) out: kfree(updates); + topology_update_needed = 0; return changed; }@@ -1453,6 +1466,13 @@ static void topology_schedule_update(void) schedule_work(&topology_work); } +void shared_topology_update(void) +{ + if (firmware_has_feature(FW_FEATURE_VPHN) && + lppaca_shared_proc(get_lppaca()))
Could we just check vphn_enabled here? The init routine will set this to true only if the feature is supported and we are using shared processors. Also, this routine seems a bit odd. The only place it is called from is an init routine, topology_update_init. Is there a reason this check couldn't just be in that routine, or it seems like you could just call topology_schedule_update directly from start_topology_update when vphn is initialized. -Nathan
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+ topology_schedule_update(); +} + static void topology_timer_fn(unsigned long ignored) { if (prrn_enabled && cpumask_weight(&cpu_associativity_changes_mask))@@ -1519,7 +1539,6 @@ int start_topology_update(void) if (firmware_has_feature(FW_FEATURE_PRRN)) { if (!prrn_enabled) { prrn_enabled = 1; - vphn_enabled = 0; #ifdef CONFIG_SMP rc = of_reconfig_notifier_register(&dt_update_nb); #endif@@ -1527,7 +1546,6 @@ int start_topology_update(void) } else if (firmware_has_feature(FW_FEATURE_VPHN) && lppaca_shared_proc(get_lppaca())) { if (!vphn_enabled) { - prrn_enabled = 0; vphn_enabled = 1; setup_cpu_associativity_change_counters(); init_timer_deferrable(&topology_timer);@@ -1613,9 +1631,16 @@ static int topology_update_init(void) if (topology_updates_enabled) start_topology_update(); + shared_topology_update(); + 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);