[PATCH v8 03/12] mm/demotion/dax/kmem: Set node's memory tier to MEMORY_TIER_PMEM

Aneesh Kumar K.V
2022-07-04T07:09:14Z

By default, all nodes are assigned to DEFAULT_MEMORY_TIER which
is the memory tier designated for nodes with DRAM

Set dax kmem device node's tier to MEMORY_TIER_PMEM. MEMORY_TIER_PMEM
appears below DEFAULT_MEMORY_TIER in demotion order.

Signed-off-by: Jagdish Gediya <jvgediya@linux.ibm.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
drivers/dax/kmem.c | 6 ++-
include/linux/memory-tiers.h | 5 +++
mm/memory-tiers.c | 79 ++++++++++++++++++++++++++++++++++++
3 files changed, 89 insertions(+), 1 deletion(-)

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index a37622060fff..0c03889286ac 100644
--- a/drivers/dax/kmem.c
+++ b/drivers/dax/kmem.c
@@ -11,6 +11,7 @@
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
+#include <linux/memory-tiers.h>
#include "dax-private.h"
#include "bus.h"

@@ -41,6 +42,9 @@ struct dax_kmem_data {
struct resource *res[];
};

+static unsigned int dax_kmem_memtier = MEMORY_TIER_PMEM;
+module_param(dax_kmem_memtier, uint, 0644);
+
static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
{
struct device *dev = &dev_dax->dev;
@@ -146,7 +150,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)
}

dev_set_drvdata(dev, data);
-
+ node_create_and_set_memory_tier(numa_node, dax_kmem_memtier);
return 0;

err_request_mem:
diff --git a/include/linux/memory-tiers.h b/include/linux/memory-tiers.h
index c47dbe381089..9d36ff13c954 100644
--- a/include/linux/memory-tiers.h
+++ b/include/linux/memory-tiers.h
@@ -14,9 +14,14 @@
#define MAX_MEMORY_TIER_ID 400

extern bool numa_demotion_enabled;
+int node_create_and_set_memory_tier(int node, int tier);

#else

#define numa_demotion_enabled false
+static inline int node_create_and_set_memory_tier(int node, int tier)
+{
+ return 0;
+}
#endif /* CONFIG_NUMA */
#endif /* _LINUX_MEMORY_TIERS_H */
diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c
index 2dcf70802661..fc404fcff7ff 100644
--- a/mm/memory-tiers.c
+++ b/mm/memory-tiers.c
@@ -51,6 +51,85 @@ static struct memory_tier *register_memory_tier(unsigned int tier)
return memtier;
}

+static void unregister_memory_tier(struct memory_tier *memtier)
+{
+ list_del(&memtier->list);
+ kfree(memtier);
+}
+
+static struct memory_tier *__node_get_memory_tier(int node)
+{
+ struct memory_tier *memtier;
+
+ list_for_each_entry(memtier, &memory_tiers, list) {
+ if (node_isset(node, memtier->nodelist))
+ return memtier;
+ }
+ return NULL;
+}
+
+static struct memory_tier *__get_memory_tier_from_id(int id)
+{
+ struct memory_tier *memtier;
+
+ list_for_each_entry(memtier, &memory_tiers, list) {
+ if (memtier->id == id)
+ return memtier;
+ }
+ return NULL;
+}
+
+static int __node_create_and_set_memory_tier(int node, int tier)
+{
+ int ret = 0;
+ struct memory_tier *memtier;
+
+ memtier = __get_memory_tier_from_id(tier);
+ if (!memtier) {
+ memtier = register_memory_tier(tier);
+ if (IS_ERR(memtier)) {
+ ret = -EINVAL;
+ goto out;
+ }
+ }
+ node_set(node, memtier->nodelist);
+out:
+ return ret;
+}
+
+int node_create_and_set_memory_tier(int node, int tier)
+{
+ struct memory_tier *current_tier;
+ int ret = 0;
+
+ mutex_lock(&memory_tier_lock);
+
+ current_tier = __node_get_memory_tier(node);
+ if (!current_tier) {
+ ret = __node_create_and_set_memory_tier(node, tier);
+ goto out;
+ }
+
+ if (current_tier->id == tier)
+ goto out;
+
+ node_clear(node, current_tier->nodelist);
+
+ ret = __node_create_and_set_memory_tier(node, tier);
+ if (ret) {
+ /* reset it back to older tier */
+ node_set(node, current_tier->nodelist);
+ goto out;
+ }
+ if (nodes_empty(current_tier->nodelist))
+ unregister_memory_tier(current_tier);
+out:
+ mutex_unlock(&memory_tier_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(node_create_and_set_memory_tier);
+
static unsigned int default_memtier = DEFAULT_MEMORY_TIER;
core_param(default_memory_tier, default_memtier, uint, 0644);

--
2.36.1