Add notes to system_taskq

Reviewed-by: Matthew Ahrens <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Reviewed-by: Tony Nguyen <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes #12771

Author: pcd1193182

module/os/freebsd/spl/spl_taskq.c

@@ -55,6 +55,11 @@ __FBSDID("$FreeBSD$");
 static uint_t taskq_tsd;
 static uma_zone_t taskq_zone;
 
+/*
+ * Global system-wide dynamic task queue available for all consumers. This
+ * taskq is not intended for long-running tasks; instead, a dedicated taskq
+ * should be created.
+ */
 taskq_t *system_taskq = NULL;
 taskq_t *system_delay_taskq = NULL;
 taskq_t *dynamic_taskq = NULL;

module/os/linux/spl/spl-taskq.c

@@ -51,7 +51,11 @@ module_param(spl_taskq_thread_sequential, int, 0644);
 MODULE_PARM_DESC(spl_taskq_thread_sequential,
 	"Create new taskq threads after N sequential tasks");
 
-/* Global system-wide dynamic task queue available for all consumers */
+/*
+ * Global system-wide dynamic task queue available for all consumers. This
+ * taskq is not intended for long-running tasks; instead, a dedicated taskq
+ * should be created.
+ */
 taskq_t *system_taskq;
 EXPORT_SYMBOL(system_taskq);
 /* Global dynamic task queue for long delay */