linux-kernel - [RFC 3/4] sched/idle: Disable idle call on least latency requirements

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Date:   Thu,  7 May 2020 19:07:22 +0530
From:   Parth Shah <parth@...ux.ibm.com>
To:     linux-kernel@...r.kernel.org
Cc:     peterz@...radead.org, mingo@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, qais.yousef@....com,
        chris.hyser@...cle.com, pkondeti@...eaurora.org,
        valentin.schneider@....com, rjw@...ysocki.net
Subject: [RFC 3/4] sched/idle: Disable idle call on least latency requirements

Restrict the call to deeper idle states when the given CPU has been set for
the least latency requirements

Signed-off-by: Parth Shah <parth@...ux.ibm.com>
---
 kernel/sched/idle.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index b743bf38f08f..85d72a6e2521 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -262,7 +262,8 @@ static void do_idle(void)
 		 * broadcast device expired for us, we don't want to go deep
 		 * idle as we know that the IPI is going to arrive right away.
 		 */
-		if (cpu_idle_force_poll || tick_check_broadcast_expired()) {
+		if (cpu_idle_force_poll || tick_check_broadcast_expired() ||
+		    per_cpu(nr_lat_sensitive, cpu)) {
 			tick_nohz_idle_restart_tick();
 			cpu_idle_poll();
 		} else {
-- 
2.17.2