On 29.10.24 21:20, Gregory Price 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>
---
drivers/acpi/numa/srat.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c
index 44f91f2c6c5d..a24aff38c465 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>
@@ -338,12 +339,26 @@ 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, size;
int node;
cfmws = (struct acpi_cedt_cfmws *)header;
start = cfmws->base_hpa;
- end = cfmws->base_hpa + cfmws->window_size;
+ size = cfmws->window_size;
+ end = cfmws->base_hpa + size;
+
+ /* Align memblock size to CFMW regions if possible */
+ for (align = SZ_64T; align >= SZ_256M; align >>= 1) {
+ if (IS_ALIGNED(start, align) && IS_ALIGNED(size, align))
+ break;
+ }
Are there maybe some nice tricks bi-tricks to avoid the loop and these
hardcoded limits? :)
align = 1UL << __ffs(start | end));
Assuming "unsigned long" is sufficient in this code (64bit) and "start |
end" will never be 0.
--
Cheers,
David / dhildenb
