Re: weird DirectMap2M accounting.

[Thomas Gleixner]

On Wed, 6 Jan 2016, Dave Jones wrote:
> On Wed, Jan 06, 2016 at 07:11:41PM -0500, Dave Jones wrote:
>  > On Wed, Jan 06, 2016 at 06:55:27PM -0500, Dave Jones wrote:
>  >  > I just spotted this in /proc/meminfo on an old Core2 machine with 4G.
>  >  > 
>  >  > DirectMap2M:    18446744073709543424 kB
>  >  > 
>  >  > Looks like we subtracted 8192 from 0 somewhere.
>  >  > 
>  >  > Should split_page_count() be checking that direct_pages_count > 0 ?
>  > 
>  > Ok, this diff makes that number print out as 0.
>  > 
>  > If this looks ok, I'll submit it properly, though I'd like to better
>  > understand what's happening here. Shouldn't I have 2M pages ?
> 
> Ah. We disable them when compiling with DEBUG_PAGEALLOC.
> So this is only needed in that case.
> If people think it's worth an ifdef for those two added lines I'll add it,
> but it seems pretty benign to just always check.

Agreed.

	tglx