[PATCH v2 18/18] libnvdimm/e820: Retrieve and populate correct 'target_node' info

Dan Williams
2019-11-17T18:00:32Z

Use the new phys_to_target_node() and numa_map_to_online_node() helpers
to retrieve the correct id for the 'numa_node' ("local" / online
initiator node) and 'target_node' (offline target memory node) sysfs
attributes.

Below is an example from a 4 numa node system where all the memory on
node2 is pmem / reserved. It should be noted that with the arrival of
the ACPI HMAT table and EFI Specific Purpose Memory the kernel will
start to see more platforms with reserved / performance differentiated
memory in its own numa node. Hence all the stakeholders on the Cc for
what is ostensibly a libnvdimm local patch.

=== Before ===

/* Notice no online memory on node2 at start */

# numactl --hardware
available: 3 nodes (0-1,3)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
node 0 size: 3958 MB
node 0 free: 3708 MB
node 1 cpus: 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
node 1 size: 4027 MB
node 1 free: 3871 MB
node 3 cpus:
node 3 size: 3994 MB
node 3 free: 3971 MB
node distances:
node 0 1 3
0: 10 21 21
1: 21 10 21
3: 21 21 10

/*
* Put the pmem namespace into devdax mode so it can be assigned to the
* kmem driver
*/

# ndctl create-namespace -e namespace0.0 -m devdax -f
{
"dev":"namespace0.0",
"mode":"devdax",
"map":"dev",
"size":"3.94 GiB (4.23 GB)",
"uuid":"1650af9b-9ba3-4704-acd6-10178399d9a3",
[..]
}

/* Online Persistent Memory as System RAM */

# daxctl reconfigure-device --mode=system-ram dax0.0
libdaxctl: memblock_in_dev: dax0.0: memory0: Unable to determine phys_index: Success
libdaxctl: memblock_in_dev: dax0.0: memory0: Unable to determine phys_index: Success
libdaxctl: memblock_in_dev: dax0.0: memory0: Unable to determine phys_index: Success
libdaxctl: memblock_in_dev: dax0.0: memory0: Unable to determine phys_index: Success
[
{
"chardev":"dax0.0",
"size":4225761280,
"target_node":0,
"mode":"system-ram"
}
]
reconfigured 1 device

/* Note that the memory is onlined by default to the wrong node, node0 */

# numactl --hardware
available: 3 nodes (0-1,3)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
node 0 size: 7926 MB
node 0 free: 7655 MB
node 1 cpus: 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
node 1 size: 4027 MB
node 1 free: 3871 MB
node 3 cpus:
node 3 size: 3994 MB
node 3 free: 3971 MB
node distances:
node 0 1 3
0: 10 21 21
1: 21 10 21
3: 21 21 10

=== After ===

/* Notice that the "phys_index" error messages are gone */

# daxctl reconfigure-device --mode=system-ram dax0.0
[
{
"chardev":"dax0.0",
"size":4225761280,
"target_node":2,
"mode":"system-ram"
}
]
reconfigured 1 device

/* Notice that node2 is now correctly populated */

# numactl --hardware
available: 4 nodes (0-3)
node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
node 0 size: 3958 MB
node 0 free: 3793 MB
node 1 cpus: 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
node 1 size: 4027 MB
node 1 free: 3851 MB
node 2 cpus:
node 2 size: 3968 MB
node 2 free: 3968 MB
node 3 cpus:
node 3 size: 3994 MB
node 3 free: 3908 MB
node distances:
node 0 1 2 3
0: 10 21 21 21
1: 21 10 21 21
2: 21 21 10 21
3: 21 21 21 10

Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
---
drivers/nvdimm/e820.c | 18 ++++--------------
1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/nvdimm/e820.c b/drivers/nvdimm/e820.c
index e02f60ad6c99..4cd18be9d0e9 100644
--- a/drivers/nvdimm/e820.c
+++ b/drivers/nvdimm/e820.c
@@ -7,6 +7,7 @@
#include <linux/memory_hotplug.h>
#include <linux/libnvdimm.h>
#include <linux/module.h>
+#include <linux/numa.h>

static int e820_pmem_remove(struct platform_device *pdev)
{
@@ -16,27 +17,16 @@ static int e820_pmem_remove(struct platform_device *pdev)
return 0;
}

-#ifdef CONFIG_MEMORY_HOTPLUG
-static int e820_range_to_nid(resource_size_t addr)
-{
- return memory_add_physaddr_to_nid(addr);
-}
-#else
-static int e820_range_to_nid(resource_size_t addr)
-{
- return NUMA_NO_NODE;
-}
-#endif
-
static int e820_register_one(struct resource *res, void *data)
{
struct nd_region_desc ndr_desc;
struct nvdimm_bus *nvdimm_bus = data;
+ int nid = phys_to_target_node(res->start);

memset(&ndr_desc, 0, sizeof(ndr_desc));
ndr_desc.res = res;
- ndr_desc.numa_node = e820_range_to_nid(res->start);
- ndr_desc.target_node = ndr_desc.numa_node;
+ ndr_desc.numa_node = numa_map_to_online_node(nid);
+ ndr_desc.target_node = nid;
set_bit(ND_REGION_PAGEMAP, &ndr_desc.flags);
if (!nvdimm_pmem_region_create(nvdimm_bus, &ndr_desc))
return -ENXIO;