Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Wed, 6 Jul 2016 09:30:54 +0900 | From | Minchan Kim <> | Subject | Re: [PATCH 08/31] mm, vmscan: simplify the logic deciding whether kswapd sleeps |
| |
On Tue, Jul 05, 2016 at 11:26:39AM +0100, Mel Gorman wrote:
<snip>
> > > @@ -3418,10 +3426,10 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) > > > if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL)) > > > return; > > > pgdat = zone->zone_pgdat; > > > - if (pgdat->kswapd_max_order < order) { > > > - pgdat->kswapd_max_order = order; > > > - pgdat->classzone_idx = min(pgdat->classzone_idx, classzone_idx); > > > - } > > > + if (pgdat->kswapd_classzone_idx == -1) > > > + pgdat->kswapd_classzone_idx = classzone_idx; > > > > It's tricky. Couldn't we change kswapd_classzone_idx to integer type > > and remove if above if condition? > > > > It's tricky and not necessarily better overall. It's perfectly possible > to be woken up for zone index 0 so it's changing -1 to another magic > value.
I don't get it. What is a problem with this?
diff --git a/mm/vmscan.c b/mm/vmscan.c index c538a8c..6eb23f5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -3413,9 +3413,7 @@ void wakeup_kswapd(struct zone *zone, int order, enum zone_type classzone_idx) if (!cpuset_zone_allowed(zone, GFP_KERNEL | __GFP_HARDWALL)) return; pgdat = zone->zone_pgdat; - if (pgdat->kswapd_classzone_idx == -1) - pgdat->kswapd_classzone_idx = classzone_idx; - pgdat->kswapd_classzone_idx = max(pgdat->kswapd_classzone_idx, classzone_idx); + pgdat->kswapd_classzone_idx = max_t(int, pgdat->kswapd_classzone_idx, classzone_idx); pgdat->kswapd_order = max(pgdat->kswapd_order, order); if (!waitqueue_active(&pgdat->kswapd_wait)) return;
| ![\](/images/icornerr.gif) |