Re: [PATCH 5/5] have smaps show transparent huge pages

Andrea Arcangeli
2011-02-10T18:09:58Z

On Thu, Feb 10, 2011 at 03:09:42PM +0000, Mel Gorman wrote:
> On Thu, Feb 10, 2011 at 07:01:55AM -0800, Dave Hansen wrote:
> > On Thu, 2011-02-10 at 11:20 +0000, Mel Gorman wrote:
> > > > @@ -394,6 +395,7 @@ static int smaps_pte_range(pmd_t *pmd, u
> > > > spin_lock(&walk->mm->page_table_lock);
> > > > } else {
> > > > smaps_pte_entry(*(pte_t *)pmd, addr, HPAGE_SIZE, walk);
> > > > + mss->anonymous_thp += HPAGE_SIZE;
> > >
> > > I should have thought of this for the previous patch but should this be
> > > HPAGE_PMD_SIZE instead of HPAGE_SIZE? Right now, they are the same value
> > > but they are not the same thing.
> >
> > Probably. There's also a nice BUG() in HPAGE_PMD_SIZE if the THP config
> > option is off, which is an added bonus.
> >
>
> Unless Andrea has an objection, I'd prefer to see HPAGE_PMD_SIZE.

We get there only through pmd_trans_huge, so HPAGE_PMD_SIZE is
certainly more correct, agreed.

I also think this can go in -mm after s/HPAGE_SIZE/HPAGE_PMD_SIZE/ and
after correcting the locking (see other email).

Maybe it'd be cleaner if we didn't need to cast the pmd to pte_t but I
guess this makes things simpler.

Thanks!
Andrea