Messages in this thread | | | Date | Wed, 8 Dec 2021 22:20:47 -0800 (PST) | From | Hugh Dickins <> | Subject | Re: [PATCH v4 1/1] mm: vmscan: Reduce throttling due to a failure to make progress |
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On Thu, 2 Dec 2021, Mel Gorman wrote: ... > --- a/mm/vmscan.c > +++ b/mm/vmscan.c ... > @@ -3478,14 +3520,18 @@ static void shrink_zones(struct zonelist *zonelist, struct scan_control *sc) > /* need some check for avoid more shrink_zone() */ > } > > + if (!first_pgdat) > + first_pgdat = zone->zone_pgdat; > + > /* See comment about same check for global reclaim above */ > if (zone->zone_pgdat == last_pgdat) > continue; > last_pgdat = zone->zone_pgdat; > shrink_node(zone->zone_pgdat, sc); > - consider_reclaim_throttle(zone->zone_pgdat, sc); > } > > + consider_reclaim_throttle(first_pgdat, sc);
My tmpfs swapping load (tweaked to use huge pages more heavily than in real life) is far from being a realistic load: but it was notably slowed down by your throttling mods in 5.16-rc, and this patch makes it well again - thanks.
But: it very quickly hit NULL pointer until I changed that last line to
if (first_pgdat) consider_reclaim_throttle(first_pgdat, sc);
I've given no thought as to whether that is the correct fix, or if first_pgdat should be set earlier in the loop above.
Hugh
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