[PATCH v2 2/4] sched/isolation: Improve documentation

[Leonardo Bras]

Improve documentation on housekeeping types and what to expect from
housekeeping functions.

Signed-off-by: Leonardo Bras <leobras@xxxxxxxxxx>
---
 include/linux/sched/isolation.h | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/include/linux/sched/isolation.h b/include/linux/sched/isolation.h
index 762701f295d1c..9333c28153a7a 100644
--- a/include/linux/sched/isolation.h
+++ b/include/linux/sched/isolation.h
@@ -7,18 +7,25 @@
 #include <linux/tick.h>
 
 enum hk_type {
-	HK_TYPE_TIMER,
-	HK_TYPE_RCU,
-	HK_TYPE_MISC,
-	HK_TYPE_SCHED,
-	HK_TYPE_TICK,
-	HK_TYPE_DOMAIN,
-	HK_TYPE_WQ,
-	HK_TYPE_MANAGED_IRQ,
-	HK_TYPE_KTHREAD,
+	HK_TYPE_TIMER,		/* Timer interrupt, watchdogs */
+	HK_TYPE_RCU,		/* RCU callbacks */
+	HK_TYPE_MISC,		/* Minor housekeeping categories */
+	HK_TYPE_SCHED,		/* Scheduling and idle load balancing */
+	HK_TYPE_TICK,		/* See isolcpus=nohz boot parameter */
+	HK_TYPE_DOMAIN,		/* See isolcpus=domain boot parameter*/
+	HK_TYPE_WQ,		/* Work Queues*/
+	HK_TYPE_MANAGED_IRQ,	/* See isolcpus=managed_irq boot parameter */
+	HK_TYPE_KTHREAD,	/* kernel threads */
 	HK_TYPE_MAX
 };
 
+/* Kernel parameters like nohz_full and isolcpus allow passing cpu numbers
+ * for disabling housekeeping types.
+ *
+ * The functions bellow work the opposite way, by referencing which cpus
+ * are able to perform the housekeeping type in parameter.
+ */
+
 #ifdef CONFIG_CPU_ISOLATION
 DECLARE_STATIC_KEY_FALSE(housekeeping_overridden);
 int housekeeping_any_cpu(enum hk_type type);
-- 
2.38.0