From 896b969e6732b68ee3c12ae4e1aeddf5db99bc46 Mon Sep 17 00:00:00 2001 From: Yunfeng Ye Date: Tue, 17 Nov 2020 14:19:48 +0100 Subject: [PATCH] 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 Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201117132006.660902274@linutronix.de --- kernel/time/tick-sched.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 306adeb..33c897b 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include @@ -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(); } -- 2.7.4