diff options
| -rw-r--r-- | arch/x86/mm/init_64.c | 33 |
1 files changed, 29 insertions, 4 deletions
diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 45241de66785..dca9abf2b85c 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1328,14 +1328,39 @@ int kern_addr_valid(unsigned long addr) return pfn_valid(pte_pfn(*pte)); } +/* + * Block size is the minimum amount of memory which can be hotplugged or + * hotremoved. It must be power of two and must be equal or larger than + * MIN_MEMORY_BLOCK_SIZE. + */ +#define MAX_BLOCK_SIZE (2UL << 30) + +/* Amount of ram needed to start using large blocks */ +#define MEM_SIZE_FOR_LARGE_BLOCK (64UL << 30) + static unsigned long probe_memory_block_size(void) { - unsigned long bz = MIN_MEMORY_BLOCK_SIZE; + unsigned long boot_mem_end = max_pfn << PAGE_SHIFT; + unsigned long bz; - /* if system is UV or has 64GB of RAM or more, use large blocks */ - if (is_uv_system() || ((max_pfn << PAGE_SHIFT) >= (64UL << 30))) - bz = 2UL << 30; /* 2GB */ + /* If this is UV system, always set 2G block size */ + if (is_uv_system()) { + bz = MAX_BLOCK_SIZE; + goto done; + } + /* Use regular block if RAM is smaller than MEM_SIZE_FOR_LARGE_BLOCK */ + if (boot_mem_end < MEM_SIZE_FOR_LARGE_BLOCK) { + bz = MIN_MEMORY_BLOCK_SIZE; + goto done; + } + + /* Find the largest allowed block size that aligns to memory end */ + for (bz = MAX_BLOCK_SIZE; bz > MIN_MEMORY_BLOCK_SIZE; bz >>= 1) { + if (IS_ALIGNED(boot_mem_end, bz)) + break; + } +done: pr_info("x86/mm: Memory block size: %ldMB\n", bz >> 20); return bz; |