On Mon, 29 Jun 2020 16:37:37 -0700 Dave Hansen <dave.hansen@xxxxxxxxx> wrote:
> On 6/29/20 4:30 PM, Baoquan He wrote:
> >> The only way I can plausibly think of "cleaning up" the RECLAIM_ZONE bit
> >> would be to raise our confidence that it is truly unused. That takes
> >> time, and probably a warning if we see it being set. If we don't run
> >> into anybody setting it or depending on it being set in a few years, we
> >> can remove it.
> > So adding the old bit back for compatibility looks good, thanks.
> >
> > Then we have to be very careful when adding and reviewing new
> > interface introducing, should not leave one which might be used
> > in the future.
> >
> > In fact, RECLAIM_ZONE is not completely useless. At least, when the old
> > bit 0 is set, it may enter into node_reclaim() in get_page_from_freelist(),
> > that makes it like a switch.
> >
> > get_page_from_freelist {
> >
> > ...
> > if (node_reclaim_mode == 0 ||
> > !zone_allows_reclaim(ac->preferred_zoneref->zone, zone))
> > continue;
> > ...
> > }
>
> Oh, that's a very good point. There are a couple of those around. Let
> me circle back and update the documentation and the variable name. I'll
> send out another version.
Was the omission of cc:stable deliberate?
