Messages in this thread | | | From | David Hildenbrand <> | Subject | Re: [PATCH] device-dax: use fallback nid when numa_node is invalid | Date | Wed, 28 Jul 2021 22:17:17 +0200 |
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On 28.07.21 10:22, Jia He wrote: > Previously, numa_off was set unconditionally in dummy_numa_init() > even with a fake numa node. Then ACPI set node id as NUMA_NO_NODE(-1) > after acpi_map_pxm_to_node() because it regards numa_off as turning > off the numa node. Hence dev_dax->target_node is NUMA_NO_NODE on > arm64 with fake numa. > > Without this patch, pmem can't be probed as a RAM device on arm64 if > SRAT table isn't present: > $ndctl create-namespace -fe namespace0.0 --mode=devdax --map=dev -s 1g -a 64K > kmem dax0.0: rejecting DAX region [mem 0x240400000-0x2bfffffff] with invalid node: -1 > kmem: probe of dax0.0 failed with error -22 > > This fixes it by using fallback memory_add_physaddr_to_nid() as nid. > > Suggested-by: David Hildenbrand <david@redhat.com> > Signed-off-by: Jia He <justin.he@arm.com> > --- > drivers/dax/kmem.c | 36 ++++++++++++++++++++---------------- > 1 file changed, 20 insertions(+), 16 deletions(-) > > diff --git a/drivers/dax/kmem.c b/drivers/dax/kmem.c > index ac231cc36359..749674909e51 100644 > --- a/drivers/dax/kmem.c > +++ b/drivers/dax/kmem.c > @@ -46,20 +46,7 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) > struct dax_kmem_data *data; > int rc = -ENOMEM; > int i, mapped = 0; > - int numa_node; > - > - /* > - * Ensure good NUMA information for the persistent memory. > - * Without this check, there is a risk that slow memory > - * could be mixed in a node with faster memory, causing > - * unavoidable performance issues. > - */ > - numa_node = dev_dax->target_node; > - if (numa_node < 0) { > - dev_warn(dev, "rejecting DAX region with invalid node: %d\n", > - numa_node); > - return -EINVAL; > - } > + int numa_node = dev_dax->target_node, new_node; > > data = kzalloc(struct_size(data, res, dev_dax->nr_range), GFP_KERNEL); > if (!data) > @@ -104,6 +91,20 @@ static int dev_dax_kmem_probe(struct dev_dax *dev_dax) > */ > res->flags = IORESOURCE_SYSTEM_RAM; > > + /* > + * Ensure good NUMA information for the persistent memory. > + * Without this check, there is a risk but not fatal that slow > + * memory could be mixed in a node with faster memory, causing > + * unavoidable performance issues. Furthermore, fallback node > + * id can be used when numa_node is invalid. > + */ > + if (numa_node < 0) { > + new_node = memory_add_physaddr_to_nid(range.start); > + dev_info(dev, "changing nid from %d to %d for DAX region %pR\n", > + numa_node, new_node, res); > + numa_node = new_node; > + } > + > /* > * Ensure that future kexec'd kernels will not treat > * this as RAM automatically. > @@ -141,6 +142,7 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax) > int i, success = 0; > struct device *dev = &dev_dax->dev; > struct dax_kmem_data *data = dev_get_drvdata(dev); > + int numa_node = dev_dax->target_node; > > /* > * We have one shot for removing memory, if some memory blocks were not > @@ -156,8 +158,10 @@ static void dev_dax_kmem_remove(struct dev_dax *dev_dax) > if (rc) > continue; > > - rc = remove_memory(dev_dax->target_node, range.start, > - range_len(&range)); > + if (numa_node < 0) > + numa_node = memory_add_physaddr_to_nid(range.start); > + > + rc = remove_memory(numa_node, range.start, range_len(&range)); > if (rc == 0) { > release_resource(data->res[i]); > kfree(data->res[i]); >
Note that this patch conflicts with:
https://lkml.kernel.org/r/20210723125210.29987-7-david@redhat.com
But nothing fundamental. Determining a single NID is similar to how I'm handling it for ACPI:
https://lkml.kernel.org/r/20210723125210.29987-6-david@redhat.com
-- Thanks,
David / dhildenb
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