[RFC PATCH v4 4/7] mm/demotion/dax/kmem: Set node's memory tier to MEMORY_TIER_PMEM

Aneesh Kumar K.V
2022-05-27T12:40:51Z

From: Jagdish Gediya <jvgediya@linux.ibm.com>

By default, all nodes are assigned to DEFAULT_MEMORY_TIER which
is memory tier 1 which is designated for nodes with DRAM, so it
is not the right tier for dax devices.

Set dax kmem device node's tier to MEMORY_TIER_PMEM, In future,
support should be added to distinguish the dax-devices which should
not be MEMORY_TIER_PMEM and right memory tier should be set for them.

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 | 4 ++++
mm/migrate.c | 2 ++
2 files changed, 6 insertions(+)

diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c
index a37622060fff..991782aa2448 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/migrate.h>
#include "dax-private.h"
#include "bus.h"

@@ -147,6 +148,9 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax)

dev_set_drvdata(dev, data);

+#ifdef CONFIG_TIERED_MEMORY
+ node_set_memory_tier(numa_node, MEMORY_TIER_PMEM);
+#endif
return 0;

err_request_mem:
diff --git a/mm/migrate.c b/mm/migrate.c
index d819a64db5b1..59d8558dd2ee 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2418,6 +2418,8 @@ int node_set_memory_tier(int node, int tier)

return ret;
}
+EXPORT_SYMBOL_GPL(node_set_memory_tier);
+

/**
* next_demotion_node() - Get the next node in the demotion path
--
2.36.1