On (21/06/08 17:18), Christoph Lameter didst pronounce:
> On Sat, 21 Jun 2008, Mel Gorman wrote:
>
> > --- a/mm/vmscan.c
> > +++ b/mm/vmscan.c
> > @@ -1249,15 +1249,13 @@ static unsigned long shrink_zone(int priority, struct zone *zone,
> > static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
> > struct scan_control *sc)
> > {
> > + enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask);
> > unsigned long nr_reclaimed = 0;
> > - struct zone **zones = zonelist->zones;
> > - int i;
> > -
> > + struct zone **z;
> > + struct zone *zone;
> >
> > sc->all_unreclaimable = 1;
> > - for (i = 0; zones[i] != NULL; i++) {
> > - struct zone *zone = zones[i];
> > -
> > + for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
> > if (!populated_zone(zone))
> > continue;
> > /*
> >
> > Code before - Walk the zonelist for GFP_KERNEL
>
> Before the change we walk all zones of the zonelist.
>
Yeah, but the zonelist is for GFP_KERNEL so it should not include the HIGHMEM
zones, right? The key change is that after the patch there are fewer zonelists
than get filtered.
> > Code after - Filter zonelist based on what is allowed for GFP_KERNEL
>
> After the change we walk only zones for GFP_KERNEL. Meaning no HIGHMEM
> and MOVABLE zones. Doesnt that mean that reclaim is limited to ZONE_DMA
> and ZONE_NORMAL? Is that really intended?
>
It is for GFP_KERNEL allocations but that is expected.
> If not then the following patch should return us to old behavior:
>
I think the effect of that patch is that zones get shrunk that have
nothing to do with the requestors requirements. Right?
> ---
> mm/vmscan.c | 3 +--
> 1 file changed, 1 insertion(+), 2 deletions(-)
>
> Index: linux-2.6/mm/vmscan.c
> ===================================================================
> --- linux-2.6.orig/mm/vmscan.c 2008-06-21 17:15:45.597627317 -0700
> +++ linux-2.6/mm/vmscan.c 2008-06-21 17:17:16.273293260 -0700
> @@ -1249,13 +1249,12 @@ static unsigned long shrink_zone(int pri
> static unsigned long shrink_zones(int priority, struct zonelist *zonelist,
> struct scan_control *sc)
> {
> - enum zone_type high_zoneidx = gfp_zone(sc->gfp_mask);
> unsigned long nr_reclaimed = 0;
> struct zoneref *z;
> struct zone *zone;
>
> sc->all_unreclaimable = 1;
> - for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
> + for_each_zone_zonelist(zone, z, zonelist, MAX_NR_ZONES - 1) {
> if (!populated_zone(zone))
> continue;
> /*
>
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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