On Mon, Jan 13, 2025 at 6:44 PM Gregory Price <gourry@xxxxxxxxxx> wrote:
>
> Capacity is stranded when CFMWS regions are not aligned to block size.
> On x86, block size increases with capacity (2G blocks @ 64G capacity).
>
> Use CFMWS base/size to report memory block size alignment advice.
>
> Suggested-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> Signed-off-by: Gregory Price <gourry@xxxxxxxxxx>
> Acked-by: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
> Acked-by: David Hildenbrand <david@xxxxxxxxxx>
> Acked-by: Dan Williams <dan.j.williams@xxxxxxxxx>
> Tested-by: Fan Ni <fan.ni@xxxxxxxxxxx>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
> ---
> drivers/acpi/numa/srat.c | 12 +++++++++++-
> 1 file changed, 11 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
> index 59fffe34c9d0..7526119fe945 100644
> --- a/drivers/acpi/numa/srat.c
> +++ b/drivers/acpi/numa/srat.c
> @@ -14,6 +14,7 @@
> #include <linux/errno.h>
> #include <linux/acpi.h>
> #include <linux/memblock.h>
> +#include <linux/memory.h>
> #include <linux/numa.h>
> #include <linux/nodemask.h>
> #include <linux/topology.h>
> @@ -425,13 +426,22 @@ static int __init acpi_parse_cfmws(union acpi_subtable_headers *header,
> {
> struct acpi_cedt_cfmws *cfmws;
> int *fake_pxm = arg;
> - u64 start, end;
> + u64 start, end, align;
> int node;
>
> cfmws = (struct acpi_cedt_cfmws *)header;
> start = cfmws->base_hpa;
> end = cfmws->base_hpa + cfmws->window_size;
>
> + /* Align memblock size to CFMW regions if possible */
> + align = 1UL << __ffs(start | end);
> + if (align >= SZ_256M) {
> + if (memory_block_advise_max_size(align) < 0)
> + pr_warn("CFMWS: memblock size advise failed\n");
> + } else {
> + pr_err("CFMWS: [BIOS BUG] base/size alignment violates spec\n");
> + }
> +
> /*
> * The SRAT may have already described NUMA details for all,
> * or a portion of, this CFMWS HPA range. Extend the memblks
> --
> 2.47.1
>
