Re: [PATCH 4/4] mm: vmscan: If kswapd has been running too long,allow it to sleep

From: KOSAKI Motohiro
Date: Tue May 17 2011 - 21:06:16 EST


It would be better to put cond_resched after balance_pgdat?

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 292582c..61c45d0 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2753,6 +2753,7 @@ static int kswapd(void *p)
if (!ret) {
trace_mm_vmscan_kswapd_wake(pgdat->node_id, order);
order = balance_pgdat(pgdat, order,&classzone_idx);
+ cond_resched();
}
}
return 0;

While it appears unlikely, there are bad conditions which can result
in cond_resched() being avoided.

Every reclaim priority decreasing or every shrink_zone() calling makes more
fine grained preemption. I think.


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