Re: [PATCH 2/2] kernel/sofirq: consolidate common code in tasklet_action() + tasklet_hi_action()

[Steven Rostedt]

On Thu, 15 Feb 2018 18:20:42 +0100
Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote:

> From: Ingo Molnar <mingo@xxxxxxx>
> 
> tasklet_action() + tasklet_hi_action() are almost identical.
> Move the common code from both function into __tasklet_schedule_common()
> and let both functions invoke it with different arguments.
> 
> Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
> Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> [bigeasy: splitted out from RT's "tasklet: Prevent tasklets from going
> into infinite spin in RT" and added commit message]
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
> ---
>  kernel/softirq.c | 54 +++++++++++++++---------------------------------------
>  1 file changed, 15 insertions(+), 39 deletions(-)
> 
> diff --git a/kernel/softirq.c b/kernel/softirq.c
> index 145cf6a2e7c9..fa7ed89a9fcf 100644
> --- a/kernel/softirq.c
> +++ b/kernel/softirq.c
> @@ -488,14 +488,16 @@ void __tasklet_hi_schedule(struct tasklet_struct *t)
>  }
>  EXPORT_SYMBOL(__tasklet_hi_schedule);
>  
> -static __latent_entropy void tasklet_action(struct softirq_action *a)
> +static void tasklet_action_common(struct softirq_action *a,
> +				  struct tasklet_head *tl_head,
> +				  unsigned int softirq_nr)
>  {
>  	struct tasklet_struct *list;
>  
>  	local_irq_disable();

Same issues with this code.

-- Steve

> -	list = __this_cpu_read(tasklet_vec.head);
> -	__this_cpu_write(tasklet_vec.head, NULL);
> -	__this_cpu_write(tasklet_vec.tail, this_cpu_ptr(&tasklet_vec.head));
> +	list = tl_head->head;
> +	tl_head->head = NULL;
> +	tl_head->tail = &tl_head->head;
>  	local_irq_enable();
>  
>