The WakeOvfIsDeferred code path in __call_rcu_nocb_wake() attempts to
wake rcuog when the callback count exceeds qhimark and callbacks aren't
done with their GP (newly queued or awaiting GP). However, a lot of
testing proves this wake is always redundant or useless.

In the flooding case, rcuog is always waiting for a GP to finish. So
waking up the rcuog thread is pointless. The timer wakeup adds overhead,
rcuog simply wakes up and goes back to sleep achieving nothing.

This path also adds a full memory barrier, and additional timer expiry
modifications unnecessarily.

The root cause is that WakeOvfIsDeferred fires when
!rcu_segcblist_ready_cbs() (GP not complete), but waking rcuog cannot
accelerate GP completion.

This commit therefore removes this path.

Tested with rcutorture scenarios: TREE01, TREE05, TREE08 (all NOCB
configurations) - all pass. Also stress tested using a kernel module
that floods call_rcu() to trigger the overload conditions and made the
observations confirming the findings.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 kernel/rcu/tree.h      |  1 -
 kernel/rcu/tree_nocb.h | 35 +++++++++--------------------------
 2 files changed, 9 insertions(+), 27 deletions(-)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 2265b9c2906e..653fb4ba5852 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -301,7 +301,6 @@ struct rcu_data {
 #define RCU_NOCB_WAKE_BYPASS	1
 #define RCU_NOCB_WAKE_LAZY	2
 #define RCU_NOCB_WAKE		3
-#define RCU_NOCB_WAKE_FORCE	4
 
 #define RCU_JIFFIES_TILL_FORCE_QS (1 + (HZ > 250) + (HZ > 500))
 					/* For jiffies_till_first_fqs and */
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index e6cd56603cad..daff2756cd90 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -518,10 +518,8 @@ static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
 }
 
 /*
- * Awaken the no-CBs grace-period kthread if needed, either due to it
- * legitimately being asleep or due to overload conditions.
- *
- * If warranted, also wake up the kthread servicing this CPUs queues.
+ * Awaken the no-CBs grace-period kthread if needed due to it legitimately
+ * being asleep.
  */
 static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
 				 unsigned long flags)
@@ -533,7 +531,6 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
 	long lazy_len;
 	long len;
 	struct task_struct *t;
-	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
 
 	// If we are being polled or there is no kthread, just leave.
 	t = READ_ONCE(rdp->nocb_gp_kthread);
@@ -549,22 +546,22 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
 	lazy_len = READ_ONCE(rdp->lazy_len);
 	if (was_alldone) {
 		rdp->qlen_last_fqs_check = len;
+		rcu_nocb_unlock(rdp);
 		// Only lazy CBs in bypass list
 		if (lazy_len && bypass_len == lazy_len) {
-			rcu_nocb_unlock(rdp);
 			wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE_LAZY,
 					   TPS("WakeLazy"));
 		} else if (!irqs_disabled_flags(flags)) {
 			/* ... if queue was empty ... */
-			rcu_nocb_unlock(rdp);
 			wake_nocb_gp(rdp, false);
 			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
 					    TPS("WakeEmpty"));
 		} else {
-			rcu_nocb_unlock(rdp);
 			wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE,
 					   TPS("WakeEmptyIsDeferred"));
 		}
+
+		return;
 	} else if (len > rdp->qlen_last_fqs_check + qhimark) {
 		/* ... or if many callbacks queued. */
 		rdp->qlen_last_fqs_check = len;
@@ -575,21 +572,10 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
 			rcu_advance_cbs_nowake(rdp->mynode, rdp);
 			rdp->nocb_gp_adv_time = j;
 		}
-		smp_mb(); /* Enqueue before timer_pending(). */
-		if ((rdp->nocb_cb_sleep ||
-		     !rcu_segcblist_ready_cbs(&rdp->cblist)) &&
-		    !timer_pending(&rdp_gp->nocb_timer)) {
-			rcu_nocb_unlock(rdp);
-			wake_nocb_gp_defer(rdp, RCU_NOCB_WAKE_FORCE,
-					   TPS("WakeOvfIsDeferred"));
-		} else {
-			rcu_nocb_unlock(rdp);
-			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
-		}
-	} else {
-		rcu_nocb_unlock(rdp);
-		trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
 	}
+
+	rcu_nocb_unlock(rdp);
+	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("WakeNot"));
 }
 
 static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head,
@@ -966,7 +952,6 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
 					   unsigned long flags)
 	__releases(rdp_gp->nocb_gp_lock)
 {
-	int ndw;
 	int ret;
 
 	if (!rcu_nocb_need_deferred_wakeup(rdp_gp, level)) {
@@ -974,8 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
 		return false;
 	}
 
-	ndw = rdp_gp->nocb_defer_wakeup;
-	ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
+	ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
 	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake"));
 
 	return ret;
@@ -991,7 +975,6 @@ static void do_nocb_deferred_wakeup_timer(struct timer_list *t)
 	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("Timer"));
 
 	raw_spin_lock_irqsave(&rdp->nocb_gp_lock, flags);
-	smp_mb__after_spinlock(); /* Timer expire before wakeup. */
 	do_nocb_deferred_wakeup_common(rdp, rdp, RCU_NOCB_WAKE_BYPASS, flags);
 }
 
-- 
2.34.1

Le Thu, Jan 01, 2026 at 11:34:12AM -0500, Joel Fernandes a écrit :
> @@ -974,8 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
>  		return false;
>  	}
>  
> -	ndw = rdp_gp->nocb_defer_wakeup;
> -	ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
> +	ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);

The force parameter can now be removed, right? (same applies to wake_nocb_gp()).

Other than that:

Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

-- 
Frederic Weisbecker
SUSE Labs

On Thu, Jan 08, 2026 at 04:57:26PM +0100, Frederic Weisbecker wrote:
> Le Thu, Jan 01, 2026 at 11:34:12AM -0500, Joel Fernandes a écrit :
> > @@ -974,8 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
> >  		return false;
> >  	}
> >  
> > -	ndw = rdp_gp->nocb_defer_wakeup;
> > -	ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
> > +	ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
> 
> The force parameter can now be removed, right? (same applies to wake_nocb_gp()).
> 
> Other than that:
> 
> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>

Ah true! Thanks, so the following hunk needs to be squashed into the patch
then, with the review tag. Boqun, if you want to do that please do, or I can
send it again for the next merge window.

---8<-----------------------

From: "Joel Fernandes" <joelagnelf@nvidia.com>
Subject: [PATCH] fixup! rcu/nocb: Remove unnecessary WakeOvfIsDeferred wake
 path

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
 kernel/rcu/tree.c      |  2 +-
 kernel/rcu/tree.h      |  2 +-
 kernel/rcu/tree_nocb.h | 14 +++++++-------
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 293bbd9ac3f4..2921ffb19939 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3769,7 +3769,7 @@ static void rcu_barrier_entrain(struct rcu_data *rdp)
 	}
 	rcu_nocb_unlock(rdp);
 	if (wake_nocb)
-		wake_nocb_gp(rdp, false);
+		wake_nocb_gp(rdp);
 	smp_store_release(&rdp->barrier_seq_snap, gseq);
 }
 
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 653fb4ba5852..7dfc57e9adb1 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -499,7 +499,7 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp);
 static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
 static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
 static void rcu_init_one_nocb(struct rcu_node *rnp);
-static bool wake_nocb_gp(struct rcu_data *rdp, bool force);
+static bool wake_nocb_gp(struct rcu_data *rdp);
 static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
 				  unsigned long j, bool lazy);
 static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head,
diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
index daff2756cd90..c6f1ddecc2d8 100644
--- a/kernel/rcu/tree_nocb.h
+++ b/kernel/rcu/tree_nocb.h
@@ -192,7 +192,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
 
 static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
 			   struct rcu_data *rdp,
-			   bool force, unsigned long flags)
+			   unsigned long flags)
 	__releases(rdp_gp->nocb_gp_lock)
 {
 	bool needwake = false;
@@ -225,13 +225,13 @@ static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
 /*
  * Kick the GP kthread for this NOCB group.
  */
-static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
+static bool wake_nocb_gp(struct rcu_data *rdp)
 {
 	unsigned long flags;
 	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
 
 	raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
-	return __wake_nocb_gp(rdp_gp, rdp, force, flags);
+	return __wake_nocb_gp(rdp_gp, rdp, flags);
 }
 
 #ifdef CONFIG_RCU_LAZY
@@ -553,7 +553,7 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
 					   TPS("WakeLazy"));
 		} else if (!irqs_disabled_flags(flags)) {
 			/* ... if queue was empty ... */
-			wake_nocb_gp(rdp, false);
+			wake_nocb_gp(rdp);
 			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
 					    TPS("WakeEmpty"));
 		} else {
@@ -959,7 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
 		return false;
 	}
 
-	ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
+	ret = __wake_nocb_gp(rdp_gp, rdp, flags);
 	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake"));
 
 	return ret;
@@ -1255,7 +1255,7 @@ lazy_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
 		}
 		rcu_nocb_try_flush_bypass(rdp, jiffies);
 		rcu_nocb_unlock_irqrestore(rdp, flags);
-		wake_nocb_gp(rdp, false);
+		wake_nocb_gp(rdp);
 		sc->nr_to_scan -= _count;
 		count += _count;
 		if (sc->nr_to_scan <= 0)
@@ -1640,7 +1640,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
 {
 }
 
-static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
+static bool wake_nocb_gp(struct rcu_data *rdp)
 {
 	return false;
 }
-- 
2.34.1

On Thu, Jan 08, 2026 at 08:39:11PM -0500, Joel Fernandes wrote:
> On Thu, Jan 08, 2026 at 04:57:26PM +0100, Frederic Weisbecker wrote:
> > Le Thu, Jan 01, 2026 at 11:34:12AM -0500, Joel Fernandes a écrit :
> > > @@ -974,8 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
> > >  		return false;
> > >  	}
> > >  
> > > -	ndw = rdp_gp->nocb_defer_wakeup;
> > > -	ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
> > > +	ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
> > 
> > The force parameter can now be removed, right? (same applies to wake_nocb_gp()).
> > 
> > Other than that:
> > 
> > Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
> 
> Ah true! Thanks, so the following hunk needs to be squashed into the patch
> then, with the review tag. Boqun, if you want to do that please do, or I can
> send it again for the next merge window.
> 

We still have time for this merge window, but I see there is still
reviewing going on for other patches, maybe you could resend these 3
patches once we reach agreement, and then we can decide which merge
window. Thoughts?

Regards,
Boqun

> ---8<-----------------------
> 
> From: "Joel Fernandes" <joelagnelf@nvidia.com>
> Subject: [PATCH] fixup! rcu/nocb: Remove unnecessary WakeOvfIsDeferred wake
>  path
> 
> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
> ---
>  kernel/rcu/tree.c      |  2 +-
>  kernel/rcu/tree.h      |  2 +-
>  kernel/rcu/tree_nocb.h | 14 +++++++-------
>  3 files changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
> index 293bbd9ac3f4..2921ffb19939 100644
> --- a/kernel/rcu/tree.c
> +++ b/kernel/rcu/tree.c
> @@ -3769,7 +3769,7 @@ static void rcu_barrier_entrain(struct rcu_data *rdp)
>  	}
>  	rcu_nocb_unlock(rdp);
>  	if (wake_nocb)
> -		wake_nocb_gp(rdp, false);
> +		wake_nocb_gp(rdp);
>  	smp_store_release(&rdp->barrier_seq_snap, gseq);
>  }
>  
> diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
> index 653fb4ba5852..7dfc57e9adb1 100644
> --- a/kernel/rcu/tree.h
> +++ b/kernel/rcu/tree.h
> @@ -499,7 +499,7 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp);
>  static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
>  static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
>  static void rcu_init_one_nocb(struct rcu_node *rnp);
> -static bool wake_nocb_gp(struct rcu_data *rdp, bool force);
> +static bool wake_nocb_gp(struct rcu_data *rdp);
>  static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
>  				  unsigned long j, bool lazy);
>  static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head,
> diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
> index daff2756cd90..c6f1ddecc2d8 100644
> --- a/kernel/rcu/tree_nocb.h
> +++ b/kernel/rcu/tree_nocb.h
> @@ -192,7 +192,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
>  
>  static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
>  			   struct rcu_data *rdp,
> -			   bool force, unsigned long flags)
> +			   unsigned long flags)
>  	__releases(rdp_gp->nocb_gp_lock)
>  {
>  	bool needwake = false;
> @@ -225,13 +225,13 @@ static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
>  /*
>   * Kick the GP kthread for this NOCB group.
>   */
> -static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
> +static bool wake_nocb_gp(struct rcu_data *rdp)
>  {
>  	unsigned long flags;
>  	struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
>  
>  	raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
> -	return __wake_nocb_gp(rdp_gp, rdp, force, flags);
> +	return __wake_nocb_gp(rdp_gp, rdp, flags);
>  }
>  
>  #ifdef CONFIG_RCU_LAZY
> @@ -553,7 +553,7 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
>  					   TPS("WakeLazy"));
>  		} else if (!irqs_disabled_flags(flags)) {
>  			/* ... if queue was empty ... */
> -			wake_nocb_gp(rdp, false);
> +			wake_nocb_gp(rdp);
>  			trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
>  					    TPS("WakeEmpty"));
>  		} else {
> @@ -959,7 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
>  		return false;
>  	}
>  
> -	ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
> +	ret = __wake_nocb_gp(rdp_gp, rdp, flags);
>  	trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake"));
>  
>  	return ret;
> @@ -1255,7 +1255,7 @@ lazy_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
>  		}
>  		rcu_nocb_try_flush_bypass(rdp, jiffies);
>  		rcu_nocb_unlock_irqrestore(rdp, flags);
> -		wake_nocb_gp(rdp, false);
> +		wake_nocb_gp(rdp);
>  		sc->nr_to_scan -= _count;
>  		count += _count;
>  		if (sc->nr_to_scan <= 0)
> @@ -1640,7 +1640,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
>  {
>  }
>  
> -static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
> +static bool wake_nocb_gp(struct rcu_data *rdp)
>  {
>  	return false;
>  }
> -- 
> 2.34.1
> 

> On Jan 9, 2026, at 5:32 AM, Boqun Feng <boqun.feng@gmail.com> wrote:
> 
> On Thu, Jan 08, 2026 at 08:39:11PM -0500, Joel Fernandes wrote:
>>> On Thu, Jan 08, 2026 at 04:57:26PM +0100, Frederic Weisbecker wrote:
>>> Le Thu, Jan 01, 2026 at 11:34:12AM -0500, Joel Fernandes a écrit :
>>>> @@ -974,8 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
>>>>        return false;
>>>>    }
>>>> 
>>>> -    ndw = rdp_gp->nocb_defer_wakeup;
>>>> -    ret = __wake_nocb_gp(rdp_gp, rdp, ndw == RCU_NOCB_WAKE_FORCE, flags);
>>>> +    ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
>>> 
>>> The force parameter can now be removed, right? (same applies to wake_nocb_gp()).
>>> 
>>> Other than that:
>>> 
>>> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
>> 
>> Ah true! Thanks, so the following hunk needs to be squashed into the patch
>> then, with the review tag. Boqun, if you want to do that please do, or I can
>> send it again for the next merge window.
>> 
> 
> We still have time for this merge window, but I see there is still
> reviewing going on for other patches, maybe you could resend these 3
> patches once we reach agreement, and then we can decide which merge
> window. Thoughts?

Yes, or let us drop these 3 for this merge window and since I am doing the next
merge window, I will include these after agreement.  I have 3 more patches
as well in this area coming up.

So I will re-send all of them together for nocb.

That will also make it easier for you and Frederic.

If by chance, we conclude review and agreement in time for this window, you could add them too, for now ok to drop nocb ones.

Thanks!

 - Joel

> 
> Regards,
> Boqun
> 
>> ---8<-----------------------
>> 
>> From: "Joel Fernandes" <joelagnelf@nvidia.com>
>> Subject: [PATCH] fixup! rcu/nocb: Remove unnecessary WakeOvfIsDeferred wake
>> path
>> 
>> Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
>> ---
>> kernel/rcu/tree.c      |  2 +-
>> kernel/rcu/tree.h      |  2 +-
>> kernel/rcu/tree_nocb.h | 14 +++++++-------
>> 3 files changed, 9 insertions(+), 9 deletions(-)
>> 
>> diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
>> index 293bbd9ac3f4..2921ffb19939 100644
>> --- a/kernel/rcu/tree.c
>> +++ b/kernel/rcu/tree.c
>> @@ -3769,7 +3769,7 @@ static void rcu_barrier_entrain(struct rcu_data *rdp)
>>    }
>>    rcu_nocb_unlock(rdp);
>>    if (wake_nocb)
>> -        wake_nocb_gp(rdp, false);
>> +        wake_nocb_gp(rdp);
>>    smp_store_release(&rdp->barrier_seq_snap, gseq);
>> }
>> 
>> diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
>> index 653fb4ba5852..7dfc57e9adb1 100644
>> --- a/kernel/rcu/tree.h
>> +++ b/kernel/rcu/tree.h
>> @@ -499,7 +499,7 @@ static void zero_cpu_stall_ticks(struct rcu_data *rdp);
>> static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
>> static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq);
>> static void rcu_init_one_nocb(struct rcu_node *rnp);
>> -static bool wake_nocb_gp(struct rcu_data *rdp, bool force);
>> +static bool wake_nocb_gp(struct rcu_data *rdp);
>> static bool rcu_nocb_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp,
>>                  unsigned long j, bool lazy);
>> static void call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *head,
>> diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h
>> index daff2756cd90..c6f1ddecc2d8 100644
>> --- a/kernel/rcu/tree_nocb.h
>> +++ b/kernel/rcu/tree_nocb.h
>> @@ -192,7 +192,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
>> 
>> static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
>>               struct rcu_data *rdp,
>> -               bool force, unsigned long flags)
>> +               unsigned long flags)
>>    __releases(rdp_gp->nocb_gp_lock)
>> {
>>    bool needwake = false;
>> @@ -225,13 +225,13 @@ static bool __wake_nocb_gp(struct rcu_data *rdp_gp,
>> /*
>>  * Kick the GP kthread for this NOCB group.
>>  */
>> -static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
>> +static bool wake_nocb_gp(struct rcu_data *rdp)
>> {
>>    unsigned long flags;
>>    struct rcu_data *rdp_gp = rdp->nocb_gp_rdp;
>> 
>>    raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags);
>> -    return __wake_nocb_gp(rdp_gp, rdp, force, flags);
>> +    return __wake_nocb_gp(rdp_gp, rdp, flags);
>> }
>> 
>> #ifdef CONFIG_RCU_LAZY
>> @@ -553,7 +553,7 @@ static void __call_rcu_nocb_wake(struct rcu_data *rdp, bool was_alldone,
>>                       TPS("WakeLazy"));
>>        } else if (!irqs_disabled_flags(flags)) {
>>            /* ... if queue was empty ... */
>> -            wake_nocb_gp(rdp, false);
>> +            wake_nocb_gp(rdp);
>>            trace_rcu_nocb_wake(rcu_state.name, rdp->cpu,
>>                        TPS("WakeEmpty"));
>>        } else {
>> @@ -959,7 +959,7 @@ static bool do_nocb_deferred_wakeup_common(struct rcu_data *rdp_gp,
>>        return false;
>>    }
>> 
>> -    ret = __wake_nocb_gp(rdp_gp, rdp, false, flags);
>> +    ret = __wake_nocb_gp(rdp_gp, rdp, flags);
>>    trace_rcu_nocb_wake(rcu_state.name, rdp->cpu, TPS("DeferredWake"));
>> 
>>    return ret;
>> @@ -1255,7 +1255,7 @@ lazy_rcu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc)
>>        }
>>        rcu_nocb_try_flush_bypass(rdp, jiffies);
>>        rcu_nocb_unlock_irqrestore(rdp, flags);
>> -        wake_nocb_gp(rdp, false);
>> +        wake_nocb_gp(rdp);
>>        sc->nr_to_scan -= _count;
>>        count += _count;
>>        if (sc->nr_to_scan <= 0)
>> @@ -1640,7 +1640,7 @@ static void rcu_init_one_nocb(struct rcu_node *rnp)
>> {
>> }
>> 
>> -static bool wake_nocb_gp(struct rcu_data *rdp, bool force)
>> +static bool wake_nocb_gp(struct rcu_data *rdp)
>> {
>>    return false;
>> }
>> --
>> 2.34.1
>> 

On Fri, Jan 09, 2026 at 06:20:20AM -0500, Joel Fernandes wrote:
> 
[...]
> >>> 
> >>> Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
> >> 
> >> Ah true! Thanks, so the following hunk needs to be squashed into the patch
> >> then, with the review tag. Boqun, if you want to do that please do, or I can
> >> send it again for the next merge window.
> >> 
> > 
> > We still have time for this merge window, but I see there is still
> > reviewing going on for other patches, maybe you could resend these 3
> > patches once we reach agreement, and then we can decide which merge
> > window. Thoughts?
> 
> Yes, or let us drop these 3 for this merge window and since I am doing the next
> merge window, I will include these after agreement.  I have 3 more patches
> as well in this area coming up.
> 
> So I will re-send all of them together for nocb.
> 
> That will also make it easier for you and Frederic.
> 
> If by chance, we conclude review and agreement in time for this window, you could add them too, for now ok to drop nocb ones.
> 

Given that we still have some ongoing discussion on other nocb patches,
I dropped the 3 nocb patches for now, I think we can still have them if
we finalize next week. Thanks!

Regards,
Boqun