Add a new function to "adjust" the current fixed UV memory block size of
2GB so it can be changed to a different physical boundary. This is out
of necessity so UV BIOS can accommodate Intel BIOS changes for NVDIMM's,
which can align these new PMEM modules at other than 2GB boundaries.
A "set order" type of function was used to insure that the memory block
size will be a power of two value without requiring a validity check on
the size value passed in. 64GB was chosen as the upper limit for memory
block size values to accommodate upcoming 4PB systems which have 6 more
bits of physical address space (46 becoming 52).
Signed-off-by: Mike Travis <mike.travis@xxxxxxx>
Reviewed-by: Andrew Banman <andrew.banman@xxxxxxx>
---
arch/x86/mm/init_64.c | 20 ++++++++++++++++----
include/linux/memory.h | 1 +
2 files changed, 17 insertions(+), 4 deletions(-)
--- linux.orig/arch/x86/mm/init_64.c
+++ linux/arch/x86/mm/init_64.c
@@ -1350,16 +1350,28 @@ int kern_addr_valid(unsigned long addr)
/* Amount of ram needed to start using large blocks */
#define MEM_SIZE_FOR_LARGE_BLOCK (64UL << 30)
+/* Adjustable memory block size */
+static unsigned long set_memory_block_size;
+int __init set_memory_block_size_order(unsigned int order)
+{
+ unsigned long size = 1UL << order;
+
+ if (size > MEM_SIZE_FOR_LARGE_BLOCK || size < MIN_MEMORY_BLOCK_SIZE)
+ return -EINVAL;
+
+ set_memory_block_size = size;
+ return 0;
+}
+
static unsigned long probe_memory_block_size(void)
{
unsigned long boot_mem_end = max_pfn << PAGE_SHIFT;
unsigned long bz;
- /* If this is UV system, always set 2G block size */
- if (is_uv_system()) {
- bz = MAX_BLOCK_SIZE;
+ /* If memory block size has been set, then use it */
+ bz = set_memory_block_size;
+ if (bz)
goto done;
- }
/* Use regular block if RAM is smaller than MEM_SIZE_FOR_LARGE_BLOCK */
if (boot_mem_end < MEM_SIZE_FOR_LARGE_BLOCK) {
--- linux.orig/include/linux/memory.h
+++ linux/include/linux/memory.h
@@ -38,6 +38,7 @@ struct memory_block {
int arch_get_memory_phys_device(unsigned long start_pfn);
unsigned long memory_block_size_bytes(void);
+int set_memory_block_size_order(unsigned int order);
/* These states are exposed to userspace as text strings in sysfs */
#define MEM_ONLINE (1<<0) /* exposed to userspace */
--
