[RFC v4 2/3] powerpc migration/cpu: Associativity & cpu changes
Michael Bringmann
mwb at linux.vnet.ibm.com
Sat May 19 06:12:48 AEST 2018
On 05/18/2018 02:28 PM, Nathan Fontenot wrote:
> On 05/17/2018 05:26 PM, Michael Bringmann wrote:
>> powerpc migration/cpu: Now apply changes to the associativity of cpus
>> for the topology of LPARS in Post Migration events. Recognize more
>> changes to the associativity of memory blocks described by the
>> 'cpu' properties when processing the topology of LPARS in Post Migration
>> events. Previous efforts only recognized whether a memory block's
>> assignment had changed in the property. Changes here include:
>>
>> * Provide hotplug CPU 'readd by index' operation
>> * Checking for changes in cpu associativity and making 'readd' calls
>> when differences are observed.
>> * Queue up changes to CPU properties so that they may take place
>> after all PowerPC device-tree changes have been applied i.e. after
>> the device hotplug is released in the mobility code.
>
> This kinda feels like three different patches in one. any reason to not split
> this into three patches? Perhaps at the least split the last item into it's
> own patch.
E.g.
1) Conditional 'acquire_drc'
2) PSERIES_HP_ELOG_ACTION_READD call to dlpar_cpu_readd_by_index
3) Add lock/unlock device hotplug
>
>>
>> Signed-off-by: Michael Bringmann <mwb at linux.vnet.ibm.com>
>> ---
>> Changes include:
>> -- Rearrange patches to co-locate CPU property-related changes.
>> -- Modify dlpar_cpu_add & dlpar_cpu_remove to skip DRC index acquire
>> or release operations during the CPU readd process.
>> -- Correct a bug in DRC index selection for queued operation.
>> -- Rebase to 4.17-rc5 kernel
>> ---
>> arch/powerpc/platforms/pseries/hotplug-cpu.c | 123 +++++++++++++++++++-------
>> arch/powerpc/platforms/pseries/mobility.c | 3 +
>> 2 files changed, 95 insertions(+), 31 deletions(-)
>>
>> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> index a408217..23d4cb8 100644
>> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
>> @@ -474,7 +474,7 @@ static bool valid_cpu_drc_index(struct device_node *parent, u32 drc_index)
>> &cdata);
>> }
>>
>> -static ssize_t dlpar_cpu_add(u32 drc_index)
>> +static ssize_t dlpar_cpu_add(u32 drc_index, bool acquire_drc)
>> {
>> struct device_node *dn, *parent;
>> int rc, saved_rc;
>> @@ -499,19 +499,22 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>> return -EINVAL;
>> }
>>
>> - rc = dlpar_acquire_drc(drc_index);
>> - if (rc) {
>> - pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
>> - rc, drc_index);
>> - of_node_put(parent);
>> - return -EINVAL;
>> + if (acquire_drc) {
>> + rc = dlpar_acquire_drc(drc_index);
>> + if (rc) {
>> + pr_warn("Failed to acquire DRC, rc: %d, drc index: %x\n",
>> + rc, drc_index);
>> + of_node_put(parent);
>> + return -EINVAL;
>> + }
>> }
>>
>> dn = dlpar_configure_connector(cpu_to_be32(drc_index), parent);
>> if (!dn) {
>> pr_warn("Failed call to configure-connector, drc index: %x\n",
>> drc_index);
>> - dlpar_release_drc(drc_index);
>> + if (acquire_drc)
>> + dlpar_release_drc(drc_index);
>> of_node_put(parent);
>> return -EINVAL;
>> }
>> @@ -526,8 +529,9 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>> pr_warn("Failed to attach node %s, rc: %d, drc index: %x\n",
>> dn->name, rc, drc_index);
>>
>> - rc = dlpar_release_drc(drc_index);
>> - if (!rc)
>> + if (acquire_drc)
>> + rc = dlpar_release_drc(drc_index);
>> + if (!rc || acquire_drc)
>> dlpar_free_cc_nodes(dn);
>
> This seems like it would be more readable if everything were inside the
> if (acquire_drc) block.
>
>>
>> return saved_rc;
>> @@ -540,7 +544,7 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>> dn->name, rc, drc_index);
>>
>> rc = dlpar_detach_node(dn);
>> - if (!rc)
>> + if (!rc && acquire_drc)
>> dlpar_release_drc(drc_index);
>>
>> return saved_rc;
>> @@ -608,12 +612,13 @@ static int dlpar_offline_cpu(struct device_node *dn)
>>
>> }
>>
>> -static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
>> +static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index,
>> + bool release_drc)
>> {
>> int rc;
>>
>> - pr_debug("Attempting to remove CPU %s, drc index: %x\n",
>> - dn->name, drc_index);
>> + pr_debug("Attempting to remove CPU %s, drc index: %x (%d)\n",
>> + dn->name, drc_index, release_drc);
>>
>> rc = dlpar_offline_cpu(dn);
>> if (rc) {
>> @@ -621,12 +626,14 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
>> return -EINVAL;
>> }
>>
>> - rc = dlpar_release_drc(drc_index);
>> - if (rc) {
>> - pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
>> - drc_index, dn->name, rc);
>> - dlpar_online_cpu(dn);
>> - return rc;
>> + if (release_drc) {
>> + rc = dlpar_release_drc(drc_index);
>> + if (rc) {
>> + pr_warn("Failed to release drc (%x) for CPU %s, rc: %d\n",
>> + drc_index, dn->name, rc);
>> + dlpar_online_cpu(dn);
>> + return rc;
>> + }
>> }
>>
>> rc = dlpar_detach_node(dn);
>> @@ -635,7 +642,8 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index)
>>
>> pr_warn("Failed to detach CPU %s, rc: %d", dn->name, rc);
>>
>> - rc = dlpar_acquire_drc(drc_index);
>> + if (release_drc)
>> + rc = dlpar_acquire_drc(drc_index);
>> if (!rc)
>> dlpar_online_cpu(dn);
>>
>> @@ -664,7 +672,7 @@ static struct device_node *cpu_drc_index_to_dn(u32 drc_index)
>> return dn;
>> }
>>
>> -static int dlpar_cpu_remove_by_index(u32 drc_index)
>> +static int dlpar_cpu_remove_by_index(u32 drc_index, bool release_drc)
>> {
>> struct device_node *dn;
>> int rc;
>> @@ -676,10 +684,30 @@ static int dlpar_cpu_remove_by_index(u32 drc_index)
>> return -ENODEV;
>> }
>>
>> - rc = dlpar_cpu_remove(dn, drc_index);
>> + rc = dlpar_cpu_remove(dn, drc_index, release_drc);
>> of_node_put(dn);
>> return rc;
>> }
>> +
>> +static int dlpar_cpu_readd_by_index(u32 drc_index)
>> +{
>> + int rc = 0;
>
> No need to initialize to 0 here.
>
>> +
>> + pr_info("Attempting to re-add CPU, drc index %x\n", drc_index);
>> +
>> + rc = dlpar_cpu_remove_by_index(drc_index, false);
>> + if (!rc)
>> + rc = dlpar_cpu_add(drc_index, false);
>> +
>> + if (rc)
>> + pr_info("Failed to update cpu at drc_index %lx\n",
>> + (unsigned long int)drc_index);
>> + else
>> + pr_info("CPU at drc_index %lx was updated\n",
>> + (unsigned long int)drc_index);
>> +
>> + return rc;
>> +}
>>
>> static int find_dlpar_cpus_to_remove(u32 *cpu_drcs, int cpus_to_remove)
>> {
>> @@ -741,7 +769,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
>> }
>>
>> for (i = 0; i < cpus_to_remove; i++) {
>> - rc = dlpar_cpu_remove_by_index(cpu_drcs[i]);
>> + rc = dlpar_cpu_remove_by_index(cpu_drcs[i], true);
>> if (rc)
>> break;
>>
>> @@ -752,7 +780,7 @@ static int dlpar_cpu_remove_by_count(u32 cpus_to_remove)
>> pr_warn("CPU hot-remove failed, adding back removed CPUs\n");
>>
>> for (i = 0; i < cpus_removed; i++)
>> - dlpar_cpu_add(cpu_drcs[i]);
>> + dlpar_cpu_add(cpu_drcs[i], true);
>>
>> rc = -EINVAL;
>> } else {
>> @@ -843,7 +871,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
>> }
>>
>> for (i = 0; i < cpus_to_add; i++) {
>> - rc = dlpar_cpu_add(cpu_drcs[i]);
>> + rc = dlpar_cpu_add(cpu_drcs[i], true);
>> if (rc)
>> break;
>>
>> @@ -854,7 +882,7 @@ static int dlpar_cpu_add_by_count(u32 cpus_to_add)
>> pr_warn("CPU hot-add failed, removing any added CPUs\n");
>>
>> for (i = 0; i < cpus_added; i++)
>> - dlpar_cpu_remove_by_index(cpu_drcs[i]);
>> + dlpar_cpu_remove_by_index(cpu_drcs[i], true);
>>
>> rc = -EINVAL;
>> } else {
>> @@ -880,7 +908,7 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
>> if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
>> rc = dlpar_cpu_remove_by_count(count);
>> else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
>> - rc = dlpar_cpu_remove_by_index(drc_index);
>> + rc = dlpar_cpu_remove_by_index(drc_index, true);
>> else
>> rc = -EINVAL;
>> break;
>> @@ -888,10 +916,13 @@ int dlpar_cpu(struct pseries_hp_errorlog *hp_elog)
>> if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT)
>> rc = dlpar_cpu_add_by_count(count);
>> else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX)
>> - rc = dlpar_cpu_add(drc_index);
>> + rc = dlpar_cpu_add(drc_index, true);
>> else
>> rc = -EINVAL;
>> break;
>> + case PSERIES_HP_ELOG_ACTION_READD:
>> + rc = dlpar_cpu_readd_by_index(drc_index);
>> + break;
>> default:
>> pr_err("Invalid action (%d) specified\n", hp_elog->action);
>> rc = -EINVAL;
>> @@ -913,7 +944,7 @@ static ssize_t dlpar_cpu_probe(const char *buf, size_t count)
>> if (rc)
>> return -EINVAL;
>>
>> - rc = dlpar_cpu_add(drc_index);
>> + rc = dlpar_cpu_add(drc_index, true);
>>
>> return rc ? rc : count;
>> }
>> @@ -934,7 +965,7 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count)
>> return -EINVAL;
>> }
>>
>> - rc = dlpar_cpu_remove(dn, drc_index);
>> + rc = dlpar_cpu_remove(dn, drc_index, true);
>> of_node_put(dn);
>>
>> return rc ? rc : count;
>> @@ -942,12 +973,38 @@ static ssize_t dlpar_cpu_release(const char *buf, size_t count)
>>
>> #endif /* CONFIG_ARCH_CPU_PROBE_RELEASE */
>>
>> +static int pseries_update_cpu(struct of_reconfig_data *pr)
>> +{
>> + /* So far, we only handle the 'ibm,associativity' property,
>> + * here.
>> + */
>> + struct pseries_hp_errorlog *hp_elog;
>> +
>> + hp_elog = kzalloc(sizeof(*hp_elog), GFP_KERNEL);
>> + if(!hp_elog)
>> + return -ENOMEM;
>
> You seem to have some odd indentation here, may want to run this through checkpatch
Okay. I think it happened on one of my build systems which was setting 'ts=4'.
>
> Also, I think queue_hotplug_event() makes a copy of the hotplug event passed in. If
> so you could just use a hp_elog struct on the stack and avoid the allocation.
Okay.
>
> -Nathan
Thanks.
Michael
>
>> +
>> + hp_elog->resource = PSERIES_HP_ELOG_RESOURCE_CPU;
>> + hp_elog->action = PSERIES_HP_ELOG_ACTION_READD;
>> + hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_INDEX;
>> + hp_elog->_drc_u.drc_index = be32_to_cpu(pr->dn->phandle);
>> +
>> + queue_hotplug_event(hp_elog, NULL, NULL);
>> +
>> + kfree(hp_elog);
>> +
>> + return 0;
>> +}
>> +
>> static int pseries_smp_notifier(struct notifier_block *nb,
>> unsigned long action, void *data)
>> {
>> struct of_reconfig_data *rd = data;
>> int err = 0;
>>
>> + if (strcmp(rd->dn->type, "cpu"))
>> + return notifier_from_errno(err);
>> +
>> switch (action) {
>> case OF_RECONFIG_ATTACH_NODE:
>> err = pseries_add_processor(rd->dn);
>> @@ -955,6 +1012,10 @@ static int pseries_smp_notifier(struct notifier_block *nb,
>> case OF_RECONFIG_DETACH_NODE:
>> pseries_remove_processor(rd->dn);
>> break;
>> + case OF_RECONFIG_UPDATE_PROPERTY:
>> + if (!strcmp(rd->prop->name, "ibm,associativity"))
>> + err = pseries_update_cpu(rd);
>> + break;
>> }
>> return notifier_from_errno(err);
>> }
>> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
>> index 8a8033a..6d98f84 100644
>> --- a/arch/powerpc/platforms/pseries/mobility.c
>> +++ b/arch/powerpc/platforms/pseries/mobility.c
>> @@ -283,6 +283,8 @@ int pseries_devicetree_update(s32 scope)
>> if (!rtas_buf)
>> return -ENOMEM;
>>
>> + lock_device_hotplug();
>> +
>> do {
>> rc = mobility_rtas_call(update_nodes_token, rtas_buf, scope);
>> if (rc && rc != 1)
>> @@ -321,6 +323,7 @@ int pseries_devicetree_update(s32 scope)
>> } while (rc == 1);
>>
>> kfree(rtas_buf);
>> + unlock_device_hotplug();
>> return rc;
>> }
>>
>
>
--
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line 363-5196
External: (512) 286-5196
Cell: (512) 466-0650
mwb at linux.vnet.ibm.com
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