lkml.org 
[lkml]   [2021]   [Feb]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 6/6 v2] sched/fair: reduce the window for duplicated update
Date
Start to update last_blocked_load_update_tick to reduce the possibility
of another cpu starting the update one more time

Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
---

v2:
- fixed compilation error for !CONFIG_NO_HZ_COMMON reported by
kernel test robot <lkp@intel.com>

kernel/sched/fair.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 3d2ab28d5736..f939a1faa014 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7852,16 +7852,20 @@ static inline bool others_have_blocked(struct rq *rq)
return false;
}

-static inline void update_blocked_load_status(struct rq *rq, bool has_blocked)
+static inline void update_blocked_load_tick(struct rq *rq)
{
- rq->last_blocked_load_update_tick = jiffies;
+ WRITE_ONCE(rq->last_blocked_load_update_tick, jiffies);
+}

+static inline void update_blocked_load_status(struct rq *rq, bool has_blocked)
+{
if (!has_blocked)
rq->has_blocked_load = 0;
}
#else
static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) { return false; }
static inline bool others_have_blocked(struct rq *rq) { return false; }
+static inline void update_blocked_load_tick(struct rq *rq) {}
static inline void update_blocked_load_status(struct rq *rq, bool has_blocked) {}
#endif

@@ -8022,6 +8026,7 @@ static void update_blocked_averages(int cpu)
struct rq_flags rf;

rq_lock_irqsave(rq, &rf);
+ update_blocked_load_tick(rq);
update_rq_clock(rq);

decayed |= __update_blocked_others(rq, &done);
@@ -8363,7 +8368,7 @@ static bool update_nohz_stats(struct rq *rq)
if (!cpumask_test_cpu(cpu, nohz.idle_cpus_mask))
return false;

- if (!time_after(jiffies, rq->last_blocked_load_update_tick))
+ if (!time_after(jiffies, READ_ONCE(rq->last_blocked_load_update_tick)))
return true;

update_blocked_averages(cpu);
--
2.17.1
\
 
 \ /
  Last update: 2021-02-06 00:06    [W:0.206 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site