On 4/21/26 11:03 PM, [email protected] wrote:
> From: liuqiqi <[email protected]>
>
> When a cxl_dax_region is probed, set the numa_node of associated
> cxl_memdev devices to match the target node derived from the region's
> address range.
> The cxl_dax_region_probe function computes the correct target node (nid)
> via phys_to_target_node() but does not propagate this information to
> the underlying cxl_memdev devices. This can cause memory allocations
> to use an incorrect NUMA node.
>
> Environment: node0/node1 = DRAM, node2 = CXL memory.
> Before this fix:
> # cat /sys/bus/cxl/devices/mem0/numa_node
> 1
> After this fix:
> # cat /sys/bus/cxl/devices/mem0/numa_node
> 2
>
> Signed-off-by: liuqiqi <[email protected]>
Thank you for the patch but NAK. The memdev numa node reflects the same numa
node that is set for the parent 'struct pci_dev'. It's where the physical
location of the device slot is NUMA wise. It may not be the same NUMA node
compare to the region where it is based on the host physical address of the
region.
DJ
> ---
> drivers/dax/cxl.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/dax/cxl.c b/drivers/dax/cxl.c
> index 3ab39b77843d..a62af46ec31e 100644
> --- a/drivers/dax/cxl.c
> +++ b/drivers/dax/cxl.c
> @@ -4,8 +4,27 @@
> #include <linux/dax.h>
>
> #include "../cxl/cxl.h"
> +#include "../cxl/cxlmem.h"
> #include "bus.h"
>
> +static void cxl_dax_set_numa_node(struct cxl_region *cxlr, int nid)
> +{
> + struct cxl_region_params *p;
> + struct cxl_endpoint_decoder *cxled;
> + struct cxl_memdev *cxlmd;
> + int i;
> +
> + p = &cxlr->params;
> + for (i = 0; i < p->nr_targets; i++) {
> + cxled = p->targets[i];
> + if (!cxled)
> + continue;
> +
> + cxlmd = cxled_to_memdev(cxled);
> + set_dev_node(&cxlmd->dev, nid);
> + }
> +}
> +
> static int cxl_dax_region_probe(struct device *dev)
> {
> struct cxl_dax_region *cxlr_dax = to_cxl_dax_region(dev);
> @@ -28,6 +47,7 @@ static int cxl_dax_region_probe(struct device *dev)
> .size = range_len(&cxlr_dax->hpa_range),
> .memmap_on_memory = true,
> };
> + cxl_dax_set_numa_node(cxlr, nid);
>
> return PTR_ERR_OR_ZERO(devm_create_dev_dax(&data));
> }
