On 5/27/2022 5:55 PM, Aneesh Kumar K.V wrote: > From: Jagdish Gediya <jvgediya@xxxxxxxxxxxxx> > > 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@xxxxxxxxxxxxx> > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> > --- > 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 I was experimenting with this patchset and found this behaviour. Here's what I did: Boot a KVM guest with vNVDIMM device which ends up with device_dax driver by default. Use it as RAM by binding it to dax kmem driver. It now appears as RAM with a new NUMA node that is put to memtier1 (the existing tier where DRAM already exists) I can move it to memtier2 (MEMORY_RANK_PMEM) manually, but isn't that expected to happen automatically when a node with dax kmem device comes up? Regards, Bharata.
