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authorYunfeng Ye <yeyunfeng@huawei.com>2020-11-17 14:19:48 +0100
committerThomas Gleixner <tglx@linutronix.de>2020-11-19 10:48:29 +0100
commit896b969e6732b68ee3c12ae4e1aeddf5db99bc46 (patch)
treee30a383f2649a1e6f5d32ad6031c845d2571b182 /kernel/time
parent7a35bf2a6a871cd0252cd371d741e7d070b53af9 (diff)
tick/sched: Release seqcount before invoking calc_load_global()
calc_load_global() does not need the sequence count protection. [ tglx: Split it up properly and added comments ] Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20201117132006.660902274@linutronix.de
Diffstat (limited to 'kernel/time')
-rw-r--r--kernel/time/tick-sched.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 306adeb6ce4c..33c897bb88c6 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -20,6 +20,7 @@
#include <linux/sched/clock.h>
#include <linux/sched/stat.h>
#include <linux/sched/nohz.h>
+#include <linux/sched/loadavg.h>
#include <linux/module.h>
#include <linux/irq_work.h>
#include <linux/posix-timers.h>
@@ -107,7 +108,8 @@ static void tick_do_update_jiffies64(ktime_t now)
tick_period);
}
- do_timer(ticks);
+ /* Advance jiffies to complete the jiffies_seq protected job */
+ jiffies_64 += ticks;
/*
* Keep the tick_next_period variable up to date. WRITE_ONCE()
@@ -116,7 +118,15 @@ static void tick_do_update_jiffies64(ktime_t now)
WRITE_ONCE(tick_next_period,
ktime_add(last_jiffies_update, tick_period));
+ /*
+ * Release the sequence count. calc_global_load() below is not
+ * protected by it, but jiffies_lock needs to be held to prevent
+ * concurrent invocations.
+ */
write_seqcount_end(&jiffies_seq);
+
+ calc_global_load();
+
raw_spin_unlock(&jiffies_lock);
update_wall_time();
}