In page_referenced_one:
+ if (referenced)
+ clear_page_idle(page);
+ clear_page_idle(page);
Andres
On Wed, Jul 22, 2015 at 12:44 PM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
On Wed, 22 Jul 2015 19:25:28 +0300 Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> wrote:
> On Tue, Jul 21, 2015 at 04:35:00PM -0700, Andrew Morton wrote:
> > On Sun, 19 Jul 2015 15:31:16 +0300 Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> wrote:
> >
> > > As noted by Minchan, a benefit of reading idle flag from
> > > /proc/kpageflags is that one can easily filter dirty and/or unevictable
> > > pages while estimating the size of unused memory.
> > >
> > > Note that idle flag read from /proc/kpageflags may be stale in case the
> > > page was accessed via a PTE, because it would be too costly to iterate
> > > over all page mappings on each /proc/kpageflags read to provide an
> > > up-to-date value. To make sure the flag is up-to-date one has to read
> > > /proc/kpageidle first.
> >
> > Is there any value in teaching the regular old page scanner to update
> > these flags? If it's doing an rmap scan anyway...
>
> I don't understand what you mean by "regular old page scanner". Could
> you please elaborate?
Whenever kswapd or direct reclaim perform an rmap scan, take that as an
opportunity to also update PageIdle().