Re: [PATCH] powerpc/mm: Check gigantic page range correctly inside memblock

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

On Monday 03 July 2017 01:01 PM, Anshuman Khandual wrote:
> The gigantic page range received from platform actually extends
> upto (block_size * expeted_pages) starting at any given address
> instead of just a single 16GB page.
> 
> Fixes: 4792adbac9eb ("powerpc: Don't use a 16G page if beyond mem= limits")
> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com>
> ---
> Though in actual experiments never seen multiple gigantic pages (16GB)
> starting at the same address. But again its very much possible looking
> at the device tree property interfaces and depending upon what PowerVM
> provides.
> 
>   arch/powerpc/mm/hash_utils_64.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
> index f2095ce..a3f1e7d 100644
> --- a/arch/powerpc/mm/hash_utils_64.c
> +++ b/arch/powerpc/mm/hash_utils_64.c
> @@ -507,7 +507,7 @@ static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
>   	printk(KERN_INFO "Huge page(16GB) memory: "
>   			"addr = 0x%lX size = 0x%lX pages = %d\n",
>   			phys_addr, block_size, expected_pages);
> -	if (phys_addr + (16 * GB) <= memblock_end_of_DRAM()) {
> +	if (phys_addr + block_size * expected_pages <= memblock_end_of_DRAM()) {
>   		memblock_reserve(phys_addr, block_size * expected_pages);
>   		add_gpage(phys_addr, block_size, expected_pages);
>   	}
> 

This was already posted by another person.

https://lkml.kernel.org/r/20170112090906.17864-1-rui.teng@linux.vnet.ibm.com


-aneesh