[PATCH v2 3/3] powerpc/pseries: Update affinity for memory and cpus specified in a PRRN event

[Nathan Fontenot]

On 12/15/2016 04:22 PM, John Allen wrote:
> Extend the existing PRRN infrastructure to perform the actual affinity
> updating for cpus and memory in addition to the device tree updating. For
> cpus, dynamic affinity updating already appears to exist in the kernel in
> the form of arch_update_cpu_topology. For memory, we must place a READD
> operation on the hotplug queue for any phandle included in the PRRN event
> that is determined to be an LMB.
> 
> Signed-off-by: John Allen <jallen at linux.vnet.ibm.com>
> ---
> diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c
> index a26a020..8836130 100644
> --- a/arch/powerpc/kernel/rtasd.c
> +++ b/arch/powerpc/kernel/rtasd.c
> @@ -21,6 +21,7 @@
>  #include <linux/cpu.h>
>  #include <linux/workqueue.h>
>  #include <linux/slab.h>
> +#include <linux/topology.h>
> 
>  #include <asm/uaccess.h>
>  #include <asm/io.h>
> @@ -282,6 +283,7 @@ static void prrn_work_fn(struct work_struct *work)
>  	 * the RTAS event.
>  	 */
>  	pseries_devicetree_update(-prrn_update_scope);
> +	arch_update_cpu_topology();
>  }
> 
>  static DECLARE_WORK(prrn_work, prrn_work_fn);
> @@ -434,7 +436,10 @@ static void do_event_scan(void)
>  		}
> 
>  		if (error == 0) {
> -			pSeries_log_error(logdata, ERR_TYPE_RTAS_LOG, 0);
> +			if (rtas_error_type((struct rtas_error_log *)logdata) !=
> +			    RTAS_TYPE_PRRN)
> +				pSeries_log_error(logdata, ERR_TYPE_RTAS_LOG,
> +						  0);
>  			handle_rtas_event((struct rtas_error_log *)logdata);
>  		}
> 
> diff --git a/arch/powerpc/platforms/pseries/mobility.c b/arch/powerpc/platforms/pseries/mobility.c
> index a560a98..d62d48a 100644
> --- a/arch/powerpc/platforms/pseries/mobility.c
> +++ b/arch/powerpc/platforms/pseries/mobility.c
> @@ -39,6 +39,7 @@ struct update_props_workarea {
>  #define ADD_DT_NODE	0x03000000
> 
>  #define MIGRATION_SCOPE	(1)
> +#define PRRN_SCOPE -2
> 
>  static int mobility_rtas_call(int token, char *buf, s32 scope)
>  {
> @@ -236,6 +237,33 @@ static int add_dt_node(__be32 parent_phandle, __be32 drc_index)
>  	return rc;
>  }
> 
> +void pseries_prrn_update_node(__be32 phandle)
> +{
> +	struct pseries_hp_errorlog *hp_elog;
> +	struct device_node *dn;
> +
> +	hp_elog = kzalloc(sizeof(*hp_elog), GFP_KERNEL);
> +	if (!hp_elog)
> +		return;
> +
> +	dn = of_find_node_by_phandle(be32_to_cpu(phandle));

You should check for the presence of the device node prior to doing the
kzalloc, this way you can avoid the alloc/free calls in cases where it
is not needed.

Also, you do need to do a of_node_put() on the device node if it is found.

-Nathan
 
> +
> +	/*
> +	 * If the phandle was not found, assume phandle is the drc index of
> +	 * an LMB.
> +	 */
> +	if (!dn) {
> +		hp_elog->resource = PSERIES_HP_ELOG_RESOURCE_MEM;
> +		hp_elog->action = PSERIES_HP_ELOG_ACTION_READD;
> +		hp_elog->id_type = PSERIES_HP_ELOG_ID_DRC_INDEX;
> +		hp_elog->_drc_u.drc_index = phandle;
> +
> +		queue_hotplug_event(hp_elog, NULL, NULL);
> +	}
> +
> +	kfree(hp_elog);
> +}
> +
>  int pseries_devicetree_update(s32 scope)
>  {
>  	char *rtas_buf;
> @@ -274,6 +302,10 @@ int pseries_devicetree_update(s32 scope)
>  					break;
>  				case UPDATE_DT_NODE:
>  					update_dt_node(phandle, scope);
> +
> +					if (scope == PRRN_SCOPE)
> +						pseries_prrn_update_node(phandle);
> +
>  					break;
>  				case ADD_DT_NODE:
>  					drc_index = *data++;
>