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 ]

Yunfeng Ye committed 5 years ago

Commit 896b9691 parent 7a35bf21 file · +11 −1Browse files

Showing the changes to kernel (1 of 1 file). Show all

Unified · Split

@@ -20,6 +20,7 @@ · 19 unmodified lines
20	20	#include <linux/sched/clock.h>
21	21	#include <linux/sched/stat.h>
22	22	#include <linux/sched/nohz.h>
	23	+#include <linux/sched/loadavg.h>
23	24	#include <linux/module.h>
24	25	#include <linux/irq_work.h>
25	26	#include <linux/posix-timers.h>
@@ -107,7 +108,8 @@ static void tick_do_update_jiffies64(ktime_t now) · 81 unmodified lines
107	108	tick_period);
108	109	}
109	110
110		− do_timer(ticks);
	111	+ /* Advance jiffies to complete the jiffies_seq protected job */
	112	+ jiffies_64 += ticks;
111	113
112	114	/*
113	115	* Keep the tick_next_period variable up to date. WRITE_ONCE()
@@ -116,7 +118,15 @@ static void tick_do_update_jiffies64(ktime_t now) · 2 unmodified lines
116	118	WRITE_ONCE(tick_next_period,
117	119	ktime_add(last_jiffies_update, tick_period));
118	120
	121	+ /*
	122	+ * Release the sequence count. calc_global_load() below is not
	123	+ * protected by it, but jiffies_lock needs to be held to prevent
	124	+ * concurrent invocations.
	125	+ */
119	126	write_seqcount_end(&jiffies_seq);
	127	+
	128	+ calc_global_load();
	129	+
120	130	raw_spin_unlock(&jiffies_lock);
121	131	update_wall_time();
122	132	}

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