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rcu/exp: Handle RCU expedited grace period kworker allocation failure

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[ Upstream commit e7539ffc9a770f36bacedcf0fbfb4bf2f244f4a5 ]

Just like is done for the kworker performing nodes initialization,
gracefully handle the possible allocation failure of the RCU expedited
grace period main kworker.

While at it perform a rename of the related checking functions to better
reflect the expedited specifics.

Reviewed-by: Kalesh Singh <kaleshsingh@google.com>
Fixes: 9621fbee44df ("rcu: Move expedited grace period (GP) work to RT kthread_worker")
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Frederic Weisbecker 2024-01-12 16:46:16 +01:00 committed by Sasha Levin
parent 6047cdf6fc
commit eba92d62cb
2 changed files with 21 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
kernel/rcu/tree.c
View File

@ -4671,6 +4671,7 @@ static void __init rcu_start_exp_gp_kworkers(void)
rcu_exp_gp_kworker = kthread_create_worker(0, gp_kworker_name);
if (IS_ERR_OR_NULL(rcu_exp_gp_kworker)) {
pr_err("Failed to create %s!\n", gp_kworker_name);
rcu_exp_gp_kworker = NULL;
return;
}
@ -4679,6 +4680,7 @@ static void __init rcu_start_exp_gp_kworkers(void)
pr_err("Failed to create %s!\n", par_gp_kworker_name);
rcu_exp_par_gp_kworker = NULL;
kthread_destroy_worker(rcu_exp_gp_kworker);
rcu_exp_gp_kworker = NULL;
return;
}

25
kernel/rcu/tree_exp.h
View File

@ -428,7 +428,12 @@ static void sync_rcu_exp_select_node_cpus(struct kthread_work *wp)
__sync_rcu_exp_select_node_cpus(rewp);
}
static inline bool rcu_gp_par_worker_started(void)
static inline bool rcu_exp_worker_started(void)
{
return !!READ_ONCE(rcu_exp_gp_kworker);
}
static inline bool rcu_exp_par_worker_started(void)
{
return !!READ_ONCE(rcu_exp_par_gp_kworker);
}
@ -478,7 +483,12 @@ static void sync_rcu_exp_select_node_cpus(struct work_struct *wp)
__sync_rcu_exp_select_node_cpus(rewp);
}
static inline bool rcu_gp_par_worker_started(void)
static inline bool rcu_exp_worker_started(void)
{
return !!READ_ONCE(rcu_gp_wq);
}
static inline bool rcu_exp_par_worker_started(void)
{
return !!READ_ONCE(rcu_par_gp_wq);
}
@ -541,7 +551,7 @@ static void sync_rcu_exp_select_cpus(void)
rnp->exp_need_flush = false;
if (!READ_ONCE(rnp->expmask))
continue; /* Avoid early boot non-existent wq. */
if (!rcu_gp_par_worker_started() ||
if (!rcu_exp_par_worker_started() ||
rcu_scheduler_active != RCU_SCHEDULER_RUNNING ||
rcu_is_last_leaf_node(rnp)) {
/* No worker started yet or last leaf, do direct call. */
@ -952,7 +962,7 @@ static void rcu_exp_print_detail_task_stall_rnp(struct rcu_node *rnp)
*/
void synchronize_rcu_expedited(void)
{
bool boottime = (rcu_scheduler_active == RCU_SCHEDULER_INIT);
bool use_worker;
unsigned long flags;
struct rcu_exp_work rew;
struct rcu_node *rnp;
@ -963,6 +973,9 @@ void synchronize_rcu_expedited(void)
lock_is_held(&rcu_sched_lock_map),
"Illegal synchronize_rcu_expedited() in RCU read-side critical section");
use_worker = (rcu_scheduler_active != RCU_SCHEDULER_INIT) &&
rcu_exp_worker_started();
/* Is the state is such that the call is a grace period? */
if (rcu_blocking_is_gp()) {
// Note well that this code runs with !PREEMPT && !SMP.
@ -992,7 +1005,7 @@ void synchronize_rcu_expedited(void)
return; /* Someone else did our work for us. */
/* Ensure that load happens before action based on it. */
if (unlikely(boottime)) {
if (unlikely(!use_worker)) {
/* Direct call during scheduler init and early_initcalls(). */
rcu_exp_sel_wait_wake(s);
} else {
@ -1010,7 +1023,7 @@ void synchronize_rcu_expedited(void)
/* Let the next expedited grace period start. */
mutex_unlock(&rcu_state.exp_mutex);
if (likely(!boottime))
if (likely(use_worker))
synchronize_rcu_expedited_destroy_work(&rew);
}
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);