[PATCH v3 08/15] sched/isolation: Add io_queue housekeeping option

[Daniel Wagner]

Multiqueue drivers such as nvme-pci are spreading IO queues on all CPUs
for optimal performance. isolcpu users are usually more concerned about
noise on isolated CPUs. Introduce a new isolcpus mask which allows the
user to define on which CPUs IO queues should be placed.

Signed-off-by: Daniel Wagner <dwagner at suse.de>
---
 include/linux/sched/isolation.h | 15 +++++++++++++++
 kernel/sched/isolation.c        |  7 +++++++
 2 files changed, 22 insertions(+)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index 2b461129d1fa..0101d0fc8c00 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -6,6 +6,20 @@
 #include <linux/init.h>
 #include <linux/tick.h>
 
+/**
+ * enum hk_type - housekeeping cpu mask types
+ * @HK_TYPE_TIMER:	housekeeping cpu mask for timers
+ * @HK_TYPE_RCU:	housekeeping cpu mask for RCU
+ * @HK_TYPE_MISC:	housekeeping cpu mask for miscalleanous resources
+ * @HK_TYPE_SCHED:	housekeeping cpu mask for scheduling
+ * @HK_TYPE_TICK:	housekeeping cpu maks for timer tick
+ * @HK_TYPE_DOMAIN:	housekeeping cpu mask for general SMP balancing
+ *			and scheduling algoririthms
+ * @HK_TYPE_WQ:		housekeeping cpu mask for worksqueues
+ * @HK_TYPE_MANAGED_IRQ: housekeeping cpu mask for managed IRQs
+ * @HK_TYPE_KTHREAD:	housekeeping cpu mask for kthreads
+ * @HK_TYPE_IO_QUEUE:	housekeeping cpu mask for I/O queues
+ */
 enum hk_type {
 	HK_TYPE_TIMER,
 	HK_TYPE_RCU,
@@ -16,6 +30,7 @@ enum hk_type {
 	HK_TYPE_WQ,
 	HK_TYPE_MANAGED_IRQ,
 	HK_TYPE_KTHREAD,
+	HK_TYPE_IO_QUEUE,
 	HK_TYPE_MAX
 };
 
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 5891e715f00d..91d7a434330c 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -18,6 +18,7 @@ enum hk_flags {
 	HK_FLAG_WQ		= BIT(HK_TYPE_WQ),
 	HK_FLAG_MANAGED_IRQ	= BIT(HK_TYPE_MANAGED_IRQ),
 	HK_FLAG_KTHREAD		= BIT(HK_TYPE_KTHREAD),
+	HK_FLAG_IO_QUEUE	= BIT(HK_TYPE_IO_QUEUE),
 };
 
 DEFINE_STATIC_KEY_FALSE(housekeeping_overridden);
@@ -228,6 +229,12 @@ static int __init housekeeping_isolcpus_setup(char *str)
 			continue;
 		}
 
+		if (!strncmp(str, "io_queue,", 9)) {
+			str += 9;
+			flags |= HK_FLAG_IO_QUEUE;
+			continue;
+		}
+
 		/*
 		 * Skip unknown sub-parameter and validate that it is not
 		 * containing an invalid character.

-- 
2.46.0