On 16.09.2014 [14:42:20 -0500], Nathan Fontenot wrote: > > > On 09/09/2014 03:09 PM, Nishanth Aravamudan wrote: > > We have hit a few customer issues with the topology update code (VPHN > > and PRRN). It would be nice to be able to debug the notifications coming > > from the hypervisor in both cases to the LPAR, as well as to disable > > reacting to the notifications, to narrow down the source of the > > problems. Add a basic level of such functionality, similar to the numa= > > command-line parameter. > > > > Signed-off-by: Nishanth Aravamudan <n...@linux.vnet.ibm.com> > > --- > > This is pretty rough, but has been useful in the field already. I'm not > > sure if more information would be useful than this basic amount. > > > > diff --git a/Documentation/kernel-parameters.txt > > b/Documentation/kernel-parameters.txt > > index 5ae8608ca9f5..6e3b9e3a2ab4 100644 > > --- a/Documentation/kernel-parameters.txt > > +++ b/Documentation/kernel-parameters.txt > > @@ -3370,6 +3370,13 @@ bytes respectively. Such letter suffixes can also be > > entirely omitted. > > e.g. base its process migration decisions on it. > > Default is on. > > > > + topology_updates= [KNL, PPC, NUMA] > > + Format: {off | debug} > > + Specify if the kernel should ignore (off) or > > + emit more information (debug) when the > > + hypervisor sends NUMA topology updates to an > > + LPAR. > > + > > tp720= [HW,PS2] > > > > tpm_suspend_pcr=[HW,TPM] > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c > > index d7737a542fd7..72c5ad313cbe 100644 > > --- a/arch/powerpc/mm/numa.c > > +++ b/arch/powerpc/mm/numa.c > > @@ -1160,6 +1160,28 @@ static int __init early_numa(char *p) > > } > > early_param("numa", early_numa); > > > > +static int topology_updates_enabled = 1; > > +static int topology_updates_debug = 0; > > + > > +static int __init early_topology_updates(char *p) > > +{ > > + if (!p) > > + return 0; > > + > > + if (strstr(p, "off")) { > > + printk(KERN_INFO "Disabling topology updates\n"); > > + topology_updates_enabled = 0; > > + } > > + > > + if (strstr(p, "debug")) { > > + printk(KERN_INFO "Enabling topology updates debug\n"); > > + topology_updates_debug = 1; > > + } > > + > > + return 0; > > +} > > +early_param("topology_updates", early_topology_updates); > > + > > #ifdef CONFIG_MEMORY_HOTPLUG > > /* > > * Find the node associated with a hot added memory section for > > @@ -1546,6 +1568,9 @@ int arch_update_cpu_topology(void) > > struct device *dev; > > int weight, new_nid, i = 0; > > > > + if (!topology_updates_enabled) > > + return 0; > > + > > weight = cpumask_weight(&cpu_associativity_changes_mask); > > if (!weight) > > return 0; > > @@ -1610,6 +1635,25 @@ int arch_update_cpu_topology(void) > > * > > * And for the similar reason, we will skip all the following updating. > > */ > > + > > + if (topology_updates_debug) { > > + char *buf = kmalloc_array(NR_CPUS*5, sizeof(char), GFP_KERNEL); > > + cpumask_scnprintf(buf, NR_CPUS*5, &updated_cpus); > > + printk(KERN_DEBUG "Topology update for the following CPUs:\n"); > > + printk(KERN_DEBUG " %s\n", buf); > > + printk(KERN_DEBUG "cpumask_weight(&updated_cpus)) = %u\n", > > + cpumask_weight(&updated_cpus)); > > + > > + if (cpumask_weight(&updated_cpus)) { > > + for (ud = &updates[0]; ud; ud = ud->next) { > > + printk(KERN_DEBUG "cpu %d moving from node %d " > > + "to %d\n", ud->cpu, > > + ud->old_nid, ud->new_nid); > > + } > > + } > > + kfree(buf); > > + } > > + > > if (!cpumask_weight(&updated_cpus)) > > goto out; > > > > @@ -1807,8 +1851,10 @@ static const struct file_operations topology_ops = { > > > > static int topology_update_init(void) > > { > > - start_topology_update(); > > - proc_create("powerpc/topology_updates", 0644, NULL, &topology_ops); > > + if (topology_updates_enabled) { > > + start_topology_update(); > > + proc_create("powerpc/topology_updates", 0644, NULL, > > &topology_ops); > > + } > > > > Is there any reason you would want to enable topology updates at some > later point? > > If so you could still create the /proc file and update it to set > topology_updates_enabled appropriately in start_topology_update() > and stop_topology_update().
Oh, that's a good point! I'll adjust the patch accordingly (disable at boot, leave the run-time twiddle). -Nish _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev