[PATCH v2 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu()

Alex Belits
2020-03-08T03:54:05Z

From: Yuri Norov <ynorov@marvell.com>

For nohz_full CPUs the desirable behavior is to receive interrupts
generated by tick_nohz_full_kick_cpu(). But for hard isolation it's
obviously not desirable because it breaks isolation.

This patch adds check for it.

Signed-off-by: Yuri Norov <ynorov@marvell.com>
[abelits@marvell.com: updated, only exclude CPUs running isolated tasks]
Signed-off-by: Alex Belits <abelits@marvell.com>
---
kernel/time/tick-sched.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 1d4dec9d3ee7..fe4503ba1316 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/isolation.h>
#include <linux/module.h>
#include <linux/irq_work.h>
#include <linux/posix-timers.h>
@@ -262,7 +263,7 @@ static void tick_nohz_full_kick(void)
*/
void tick_nohz_full_kick_cpu(int cpu)
{
- if (!tick_nohz_full_cpu(cpu))
+ if (!tick_nohz_full_cpu(cpu) || task_isolation_on_cpu(cpu))
return;

irq_work_queue_on(&per_cpu(nohz_full_kick_work, cpu), cpu);
--
2.20.1