From: MengEn Sun <mengensun@xxxxxxxxxxx>
when a cpu stops tick, quiet_vmstat may flush all the per cpu
statistics counter.
while, the shepherd is needed those counters to kick the
vmstat_work.
when a cpu in nohz with a lot of pcp pages, and do not do page
allocating and freeing. the pcp pages of the cpu may not be hold
for a long time
we make shepherd keep a eye on the pcp high_min and high_max
Reviewed-by: Jinliang Zheng <alexjlzheng@xxxxxxxxxxx>
Signed-off-by: MengEn Sun <mengensun@xxxxxxxxxxx>
---
mm/vmstat.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 1917c034c045..32768fb8f769 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -2024,8 +2024,13 @@ static bool need_update(int cpu)
for_each_populated_zone(zone) {
struct per_cpu_zonestat *pzstats = per_cpu_ptr(zone->per_cpu_zonestats, cpu);
+ struct per_cpu_pages *pcp = per_cpu_ptr(zone->per_cpu_pageset, cpu);
struct per_cpu_nodestat *n;
+ /* in onhz or nohz full make pcp decay work */
+ if (pcp->high_max > pcp->high_min)
+ return true;
+
/*
* The fast way of checking if there are any vmstat diffs.
*/
--
2.43.5
