"Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxx> writes:
> By default, all nodes are assigned to the default memory tier which
> is the memory tier designated for nodes with DRAM
>
> Set dax kmem device node's tier to slower memory tier by assigning
> performance level to MEMTIER_PERF_LEVEL_PMEM. PMEM tier
> appears below the default memory tier in demotion order.
>
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> ---
> arch/powerpc/platforms/pseries/papr_scm.c | 41 ++++++++++++++++++++---
> drivers/acpi/nfit/core.c | 41 ++++++++++++++++++++++-
> 2 files changed, 76 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
> index 82cae08976bc..3b6164418d6f 100644
> --- a/arch/powerpc/platforms/pseries/papr_scm.c
> +++ b/arch/powerpc/platforms/pseries/papr_scm.c
> @@ -14,6 +14,8 @@
> #include <linux/delay.h>
> #include <linux/seq_buf.h>
> #include <linux/nd.h>
> +#include <linux/memory.h>
> +#include <linux/memory-tiers.h>
>
> #include <asm/plpar_wrappers.h>
> #include <asm/papr_pdsm.h>
> @@ -98,6 +100,7 @@ struct papr_scm_priv {
> bool hcall_flush_required;
>
> uint64_t bound_addr;
> + int target_node;
>
> struct nvdimm_bus_descriptor bus_desc;
> struct nvdimm_bus *bus;
> @@ -1278,6 +1281,7 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
> p->bus_desc.module = THIS_MODULE;
> p->bus_desc.of_node = p->pdev->dev.of_node;
> p->bus_desc.provider_name = kstrdup(p->pdev->name, GFP_KERNEL);
> + p->target_node = dev_to_node(&p->pdev->dev);
>
> /* Set the dimm command family mask to accept PDSMs */
> set_bit(NVDIMM_FAMILY_PAPR, &p->bus_desc.dimm_family_mask);
> @@ -1322,7 +1326,7 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
> mapping.size = p->blocks * p->block_size; // XXX: potential overflow?
>
> memset(&ndr_desc, 0, sizeof(ndr_desc));
> - target_nid = dev_to_node(&p->pdev->dev);
> + target_nid = p->target_node;
> online_nid = numa_map_to_online_node(target_nid);
> ndr_desc.numa_node = online_nid;
> ndr_desc.target_node = target_nid;
> @@ -1582,15 +1586,42 @@ static struct platform_driver papr_scm_driver = {
> },
> };
>
> +static int papr_scm_callback(struct notifier_block *self,
> + unsigned long action, void *arg)
> +{
> + struct memory_notify *mnb = arg;
> + int nid = mnb->status_change_nid;
> + struct papr_scm_priv *p;
> +
> + if (nid == NUMA_NO_NODE || action != MEM_ONLINE)
> + return NOTIFY_OK;
> +
> + mutex_lock(&papr_ndr_lock);
> + list_for_each_entry(p, &papr_nd_regions, region_list) {
> + if (p->target_node == nid) {
> + node_devices[nid]->perf_level = MEMTIER_PERF_LEVEL_PMEM;
> + break;
> + }
> + }
> +
> + mutex_unlock(&papr_ndr_lock);
> + return NOTIFY_OK;
> +}
> +
> static int __init papr_scm_init(void)
> {
> int ret;
>
> ret = platform_driver_register(&papr_scm_driver);
> - if (!ret)
> - mce_register_notifier(&mce_ue_nb);
> -
> - return ret;
> + if (ret)
> + return ret;
> + mce_register_notifier(&mce_ue_nb);
> + /*
> + * register a memory hotplug notifier at prio 2 so that we
> + * can update the perf level for the node.
> + */
> + hotplug_memory_notifier(papr_scm_callback, MEMTIER_HOTPLUG_PRIO + 1);
> + return 0;
> }
> module_init(papr_scm_init);
>
> diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c
> index ae5f4acf2675..7ea1017ef790 100644
> --- a/drivers/acpi/nfit/core.c
> +++ b/drivers/acpi/nfit/core.c
> @@ -15,6 +15,8 @@
> #include <linux/sort.h>
> #include <linux/io.h>
> #include <linux/nd.h>
> +#include <linux/memory.h>
> +#include <linux/memory-tiers.h>
> #include <asm/cacheflush.h>
> #include <acpi/nfit.h>
> #include "intel.h"
> @@ -3470,6 +3472,39 @@ static struct acpi_driver acpi_nfit_driver = {
> },
> };
>
> +static int nfit_callback(struct notifier_block *self,
> + unsigned long action, void *arg)
> +{
> + bool found = false;
> + struct memory_notify *mnb = arg;
> + int nid = mnb->status_change_nid;
> + struct nfit_spa *nfit_spa;
> + struct acpi_nfit_desc *acpi_desc;
> +
> + if (nid == NUMA_NO_NODE || action != MEM_ONLINE)
> + return NOTIFY_OK;
> +
> + mutex_lock(&acpi_desc_lock);
> + list_for_each_entry(acpi_desc, &acpi_descs, list) {
> + mutex_lock(&acpi_desc->init_mutex);
> + list_for_each_entry(nfit_spa, &acpi_desc->spas, list) {
> + struct acpi_nfit_system_address *spa = nfit_spa->spa;
> + int target_node = pxm_to_node(spa->proximity_domain);
> +
> + if (target_node == nid) {
> + node_devices[nid]->perf_level = MEMTIER_PERF_LEVEL_PMEM;
> + found = true;
> + break;
> + }
> + }
> + mutex_unlock(&acpi_desc->init_mutex);
> + if (found)
> + break;
> + }
> + mutex_unlock(&acpi_desc_lock);
> + return NOTIFY_OK;
> +}
> +
> static __init int nfit_init(void)
> {
> int ret;
> @@ -3509,7 +3544,11 @@ static __init int nfit_init(void)
> nfit_mce_unregister();
> destroy_workqueue(nfit_wq);
> }
> -
> + /*
> + * register a memory hotplug notifier at prio 2 so that we
> + * can update the perf level for the node.
> + */
> + hotplug_memory_notifier(nfit_callback, MEMTIER_HOTPLUG_PRIO + 1);
> return ret;
>
> }
I don't think that it's a good idea to set perf_level of a memory device
(node) via NFIT only.
For example, we may prefer HMAT over NFIT when it's available. So the
perf_level should be set in dax/kmem.c based on information provided by
ACPI or other information sources. ACPI can provide some functions/data
structures to let drivers (like dax/kmem.c) to query the properties of
the memory device (node).
As the simplest first version, this can be just hard coded.
Best Regards,
Huang, Ying
