When the housekeeping CPU mask for RCU is updated at runtime, RCU grace-period kthreads and tasks-RCU kthreads should be migrated to the newly designated housekeeping CPUs.
1. Implement rcu_housekeeping_reconfigure() to handle HK_UPDATE_MASK events for HK_TYPE_RCU. 2. Update the affinity of rcu_state.gp_kthread when the mask changes. 3. Register the RCU housekeeping notifier during late initialization. This ensures RCU kthreads honor dynamic isolation settings without requiring a system reboot. Signed-off-by: Qiliang Yuan <[email protected]> Signed-off-by: Qiliang Yuan <[email protected]> --- kernel/rcu/tree.c | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 293bbd9ac3f4..ec496e4bd24f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -48,6 +48,7 @@ #include <linux/delay.h> #include <linux/random.h> #include <linux/trace_events.h> +#include <linux/sched/isolation.h> #include <linux/suspend.h> #include <linux/ftrace.h> #include <linux/tick.h> @@ -4913,7 +4914,49 @@ void __init rcu_init(void) tasks_cblist_init_generic(); } +#ifdef CONFIG_SMP +static int rcu_housekeeping_reconfigure(struct notifier_block *nb, + unsigned long action, void *data) +{ + struct housekeeping_update *upd = data; + struct task_struct *t; + + if (action != HK_UPDATE_MASK || upd->type != HK_TYPE_RCU) + return NOTIFY_OK; + + t = READ_ONCE(rcu_state.gp_kthread); + if (t) + housekeeping_affine(t, HK_TYPE_RCU); + +#ifdef CONFIG_TASKS_RCU + t = get_rcu_tasks_gp_kthread(); + if (t) + housekeeping_affine(t, HK_TYPE_RCU); +#endif + +#ifdef CONFIG_TASKS_RUDE_RCU + t = get_rcu_tasks_rude_gp_kthread(); + if (t) + housekeeping_affine(t, HK_TYPE_RCU); +#endif + + return NOTIFY_OK; +} + +static struct notifier_block rcu_housekeeping_nb = { + .notifier_call = rcu_housekeeping_reconfigure, +}; + +static int __init rcu_init_housekeeping_notifier(void) +{ + housekeeping_register_notifier(&rcu_housekeeping_nb); + return 0; +} +late_initcall(rcu_init_housekeeping_notifier); +#endif + #include "tree_stall.h" #include "tree_exp.h" #include "tree_nocb.h" #include "tree_plugin.h" + -- 2.51.0
