[PATCH] mm: convert totalram_pages, totalhigh_pages and managed_pages to atomic.

[Joe Perches]

On Mon, 2018-10-22 at 22:53 +0530, Arun KS wrote:
> Remove managed_page_count_lock spinlock and instead use atomic
> variables.

Perhaps better to define and use macros for the accesses
instead of specific uses of atomic_long_<inc/dec/read>

Something like:

#define totalram_pages()	(unsigned long)atomic_long_read(&_totalram_pages)
#define totalram_pages_inc()	(unsigned long)atomic_long_inc(&_totalram_pages)
#define totalram_pages_dec()	(unsigned long)atomic_long_dec(&_totalram_pages)