This commit only make irq_work_queue() to be called when the
llist_add() returns true.

Signed-off-by: Zqiang <qiang.zhang@linux.dev>
---
 kernel/sched/ext.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
index 8f6d8d7f895c..136b01950a62 100644
--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -3439,8 +3439,8 @@ static void destroy_dsq(struct scx_sched *sch, u64 dsq_id)
 	 * operations inside scheduler locks.
 	 */
 	dsq->id = SCX_DSQ_INVALID;
-	llist_add(&dsq->free_node, &dsqs_to_free);
-	irq_work_queue(&free_dsq_irq_work);
+	if (llist_add(&dsq->free_node, &dsqs_to_free))
+		irq_work_queue(&free_dsq_irq_work);
 
 out_unlock_dsq:
 	raw_spin_unlock_irqrestore(&dsq->lock, flags);
-- 
2.17.1

On Mon, Dec 22, 2025 at 07:53:18PM +0800, Zqiang wrote:
> This commit only make irq_work_queue() to be called when the
> llist_add() returns true.

Just to be more clear, we could rephrase the commit message as follows:

llist_add() returns true only when adding to an empty list, which indicates
that no IRQ work is currently queued or running. Therefore, we only need to
call irq_work_queue() when llist_add() returns true, to avoid unnecessarily
re-queueing IRQ work that is already pending or executing.

> 
> Signed-off-by: Zqiang <qiang.zhang@linux.dev>

But overall, looks good to me.

Reviewed-by: Andrea Righi <arighi@nvidia.com>

Thanks,
-Andrea

> ---
>  kernel/sched/ext.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
> index 8f6d8d7f895c..136b01950a62 100644
> --- a/kernel/sched/ext.c
> +++ b/kernel/sched/ext.c
> @@ -3439,8 +3439,8 @@ static void destroy_dsq(struct scx_sched *sch, u64 dsq_id)
>  	 * operations inside scheduler locks.
>  	 */
>  	dsq->id = SCX_DSQ_INVALID;
> -	llist_add(&dsq->free_node, &dsqs_to_free);
> -	irq_work_queue(&free_dsq_irq_work);
> +	if (llist_add(&dsq->free_node, &dsqs_to_free))
> +		irq_work_queue(&free_dsq_irq_work);
>  
>  out_unlock_dsq:
>  	raw_spin_unlock_irqrestore(&dsq->lock, flags);
> -- 
> 2.17.1
>

> 
> On Mon, Dec 22, 2025 at 07:53:18PM +0800, Zqiang wrote:
> 
> > 
> > This commit only make irq_work_queue() to be called when the
> >  llist_add() returns true.
> > 
> Just to be more clear, we could rephrase the commit message as follows:
> 
> llist_add() returns true only when adding to an empty list, which indicates
> that no IRQ work is currently queued or running. Therefore, we only need to
> call irq_work_queue() when llist_add() returns true, to avoid unnecessarily
> re-queueing IRQ work that is already pending or executing.

Thank you for make the commit more clear and reviewed :) .

Thanks
Zqiang
 
> 
> > 
> > Signed-off-by: Zqiang <qiang.zhang@linux.dev>
> > 
> But overall, looks good to me.
> 
> Reviewed-by: Andrea Righi <arighi@nvidia.com>
> 
> Thanks,
> -Andrea
> 
> > 
> > ---
> >  kernel/sched/ext.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> >  
> >  diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c
> >  index 8f6d8d7f895c..136b01950a62 100644
> >  --- a/kernel/sched/ext.c
> >  +++ b/kernel/sched/ext.c
> >  @@ -3439,8 +3439,8 @@ static void destroy_dsq(struct scx_sched *sch, u64 dsq_id)
> >  * operations inside scheduler locks.
> >  */
> >  dsq->id = SCX_DSQ_INVALID;
> >  - llist_add(&dsq->free_node, &dsqs_to_free);
> >  - irq_work_queue(&free_dsq_irq_work);
> >  + if (llist_add(&dsq->free_node, &dsqs_to_free))
> >  + irq_work_queue(&free_dsq_irq_work);
> >  
> >  out_unlock_dsq:
> >  raw_spin_unlock_irqrestore(&dsq->lock, flags);
> >  -- 
> >  2.17.1
> >
>

Applied to sched_ext/for-6.20.

Note: Commit message updated per Andrea's suggestion.

Thanks.
--
tejun

> 
> Applied to sched_ext/for-6.20.
> 
> Note: Commit message updated per Andrea's suggestion.

Thank you for update commit message.

Thanks
Zqiang

> 
> Thanks.
> --
> tejun
>