Re: page fault scalability patch final : i386 tested, x86_64 support added

Andi Kleen
2004-08-27T23:39:42Z

> Index: linux-2.6.9-rc1/include/linux/sched.h
> ===================================================================
> --- linux-2.6.9-rc1.orig/include/linux/sched.h 2004-08-25 10:50:12.534021000 -0700
> +++ linux-2.6.9-rc1/include/linux/sched.h 2004-08-27 12:14:09.564008624 -0700
> @@ -197,9 +197,10 @@
> pgd_t * pgd;
> atomic_t mm_users; /* How many users with user space? */
> atomic_t mm_count; /* How many references to "struct mm_struct" (users count as 1) */
> + atomic_t mm_rss; /* Number of pages used by this mm struct */

atomic_t is normally 32bit, even on a 64bit arch. This will limit the max
memory size per process to 2^(32+PAGE_SHIFT). I don't think that's a good idea.

On some architectures it used to be 24bit only even, but I think that
has been fixed.

I think you need atomic64_t

-Andi