From a0db971e4eb69fc84eb3d7ef94f718b483550b4a Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Mon, 19 Jun 2017 04:12:01 +0200 Subject: [PATCH] nohz: Move idle balancer registration to the idle path The idle load balancing registration path assumes that we only stop the tick when the CPU is idle, ignoring the nohz full case. As a result, a nohz full CPU that is running a task may be chosen to perform idle load balancing. Lets make sure that only CPUs in dynticks idle mode can be picked as idle load balancers. Signed-off-by: Frederic Weisbecker Acked-by: Rik van Riel Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1497838322-10913-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar --- kernel/time/tick-sched.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index b1b58a07e042..db023e9cbb25 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -782,7 +782,6 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, * the scheduler tick in nohz_restart_sched_tick. */ if (!ts->tick_stopped) { - nohz_balance_enter_idle(cpu); calc_load_nohz_start(); cpu_load_update_nohz_start(); @@ -923,8 +922,10 @@ static void __tick_nohz_idle_enter(struct tick_sched *ts) ts->idle_expires = expires; } - if (!was_stopped && ts->tick_stopped) + if (!was_stopped && ts->tick_stopped) { ts->idle_jiffies = ts->last_jiffies; + nohz_balance_enter_idle(cpu); + } } }