Hi,
On Thu, May 13, 2010 at 12:02:53PM +0900, KOSAKI Motohiro wrote:
> sorry for the long delayed review.
Yeah, I'm a bit on the slow side as well these days. No problem.
> > The RECLAIM_SWAP flag in zone_reclaim_mode controls whether
> > zone_reclaim() is allowed to swap or not (obviously).
> >
> > This is currently implemented by allowing or forbidding reclaim to
> > unmap pages, which also controls reclaim of shared pages and is thus
> > not appropriate.
> >
> > We can do better by using the sc->may_swap parameter instead, which
> > controls whether the anon lists are scanned.
> >
> > Unmapping of pages is then allowed per default from zone_reclaim().
> >
> > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
> > ---
> > mm/vmscan.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -2563,8 +2563,8 @@ static int __zone_reclaim(struct zone *z
> > int priority;
> > struct scan_control sc = {
> > .may_writepage = !!(zone_reclaim_mode & RECLAIM_WRITE),
> > - .may_unmap = !!(zone_reclaim_mode & RECLAIM_SWAP),
> > - .may_swap = 1,
> > + .may_unmap = 1,
> > + .may_swap = !!(zone_reclaim_mode & RECLAIM_SWAP),
> > .nr_to_reclaim = max_t(unsigned long, nr_pages,
> > SWAP_CLUSTER_MAX),
> > .gfp_mask = gfp_mask,
>
> About half years ago, I did post exactly same patch. but at that time,
> it got Mel's objection. after some discution we agreed to merge
> documentation change instead code fix.
Interesting, let me dig through the archives.
> So, now the documentation describe clearly 4th bit meant no unmap.
> Please drop this, instead please make s/RECLAIM_SWAP/RECLAIM_MAPPED/ patch.
Yep.
Thanks,
Hannes
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