about arm_add_memory

[Dave Hylands]

Hi,

2011/1/11 wangjun <wj_nwpu at 163.com>:
> in  /arch/arm/kernel/setup.c
>
> static int __init arm_add_memory(unsigned long start, unsigned long size)
> ...
> size -= start & ~PAGE_MASK;
> bank->start = PAGE_ALIGN(start);
> bank->size  = size & PAGE_MASK;
> bank->node  = PHYS_TO_NID(start);
> .....
>
> what   size -= start & ~PAGE_MASK  to do ?

If you passed in a non-aligned start address, then this adjusts the
size by the same amount as bank->start = PAGE_ALIGN(start) will adjust
the start address.

Dave Hylands