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rcu: Remove swake_up_one_online() bandaid

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It's now ok to perform a wake-up from an offline CPU because the
resulting armed scheduler bandwidth hrtimers are now correctly targeted
by hrtimer infrastructure.

Remove the obsolete hackerry.

Link: https://lore.kernel.org/all/20241231170712.149394-3-frederic@kernel.org/
Reviewed-by: Usama Arif <usamaarif642@gmail.com>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
This commit is contained in:
Frederic Weisbecker
2025-05-16 09:00:54 -04:00
committed by Joel Fernandes
parent 79b265a2e7
commit 0999f61560
3 changed files with 3 additions and 35 deletions
Download Patch File Download Diff File Expand all files Collapse all files
kernel/rcu/tree.c
+1 -33
View File
@@ -1060,38 +1060,6 @@ static bool rcu_future_gp_cleanup(struct rcu_node *rnp)
return needmore;
}
static void swake_up_one_online_ipi(void *arg)
{
struct swait_queue_head *wqh = arg;
swake_up_one(wqh);
}
static void swake_up_one_online(struct swait_queue_head *wqh)
{
int cpu = get_cpu();
/*
* If called from rcutree_report_cpu_starting(), wake up
* is dangerous that late in the CPU-down hotplug process. The
* scheduler might queue an ignored hrtimer. Defer the wake up
* to an online CPU instead.
*/
if (unlikely(cpu_is_offline(cpu))) {
int target;
target = cpumask_any_and(housekeeping_cpumask(HK_TYPE_RCU),
cpu_online_mask);
smp_call_function_single(target, swake_up_one_online_ipi,
wqh, 0);
put_cpu();
} else {
put_cpu();
swake_up_one(wqh);
}
}
/*
* Awaken the grace-period kthread. Don't do a self-awaken (unless in an
* interrupt or softirq handler, in which case we just might immediately
@@ -1116,7 +1084,7 @@ static void rcu_gp_kthread_wake(void)
return;
WRITE_ONCE(rcu_state.gp_wake_time, jiffies);
WRITE_ONCE(rcu_state.gp_wake_seq, READ_ONCE(rcu_state.gp_seq));
swake_up_one_online(&rcu_state.gp_wq);
swake_up_one(&rcu_state.gp_wq);
}
/*
kernel/rcu/tree_exp.h
+1 -1
View File
@@ -200,7 +200,7 @@ static void __rcu_report_exp_rnp(struct rcu_node *rnp,
if (rnp->parent == NULL) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (wake)
swake_up_one_online(&rcu_state.expedited_wq);
swake_up_one(&rcu_state.expedited_wq);
break;
}
kernel/rcu/tree_nocb.h
+1 -1
View File
@@ -216,7 +216,7 @@ static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
raw_spin_unlock_irqrestore(&rdp_gp->nocb_gp_lock, flags);
if (needwake) {
trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DoWake"));
swake_up_one_online(&rdp_gp->nocb_gp_wq);
swake_up_one(&rdp_gp->nocb_gp_wq);
}
return needwake;