Re: [PATCH 07/24] locking: Switch to _irq_{disable,enable}() variants in cleanup guards

On Mon, Aug 03, 2026 at 03:55:47PM +0200, Peter Zijlstra wrote:
> On Mon, Aug 03, 2026 at 06:46:19AM -0700, Boqun Feng wrote:
> 
> > > What about the _irqsave() guards?
> > > 
> > > Is the goal to replace _irqsave guard usage with _irq and then remove
> > > the _irqsave guards?
> > > 
> > 
> > Yes, that's the goal. I had that in previous version. However in
> > 1abbecd1d2d2 ("sched/fair: Convert cfs bandwidth throttling to use
> > guards"), we have a user that explicitly plays with the .flags in guard. 
> > Lyude also spotted that too. We could adjust that user to the new API
> > (Lyude already has the diff for that) but I decided to simply drop that
> > part for now given the current size of the changes. But if you think
> > it's a must for merge this, I will add it.
> 
> Well, but this new stuff should be able to clean that up, no?
> 

Yeah... I admit that the decision was made based on how much time I
could spend on this cycle, rather than "what the best we can do here".

Thank you. I fold the following.

Regards,
Boqun

> ---
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -7248,7 +7248,7 @@ static bool distribute_cfs_runtime(struc
>   * period the timer is deactivated until scheduling resumes; cfs_b->idle is
>   * used to track this state.
>   */
> -static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun, unsigned long flags)
> +static int do_sched_cfs_period_timer(struct cfs_bandwidth *cfs_b, int overrun)
>  	__must_hold(&cfs_b->lock)
>  {
>  	int throttled;
> @@ -7283,10 +7283,10 @@ static int do_sched_cfs_period_timer(str
>  	 * This check is repeated as we release cfs_b->lock while we unthrottle.
>  	 */
>  	while (throttled && cfs_b->runtime > 0) {
> -		raw_spin_unlock_irqrestore(&cfs_b->lock, flags);
> +		raw_spin_unlock_irq_enable(&cfs_b->lock);
>  		/* we can't nest cfs_b->lock while distributing bandwidth */
>  		throttled = distribute_cfs_runtime(cfs_b);
> -		raw_spin_lock_irqsave(&cfs_b->lock, flags);
> +		raw_spin_lock_irq_disable(&cfs_b->lock);
>  	}
>  
>  	/*
> @@ -7394,7 +7394,7 @@ static __always_inline void return_cfs_r
>  static void do_sched_cfs_slack_timer(struct cfs_bandwidth *cfs_b)
>  {
>  	/* confirm we're still not at a refresh boundary */
> -	scoped_guard(raw_spinlock_irqsave, &cfs_b->lock) {
> +	scoped_guard(raw_spinlock_irq, &cfs_b->lock) {
>  		u64 runtime = 0, slice = sched_cfs_bandwidth_slice();
>  
>  		cfs_b->slack_started = false;
> @@ -7479,14 +7479,14 @@ static enum hrtimer_restart sched_cfs_pe
>  	int idle = 0;
>  	int count = 0;
>  
> -	CLASS(raw_spinlock_irqsave, cfsb_guard)(&cfs_b->lock);
> +	guard(raw_spinlock_irq)(&cfs_b->lock);
>  
>  	for (;;) {
>  		overrun = hrtimer_forward_now(timer, cfs_b->period);
>  		if (!overrun)
>  			break;
>  
> -		idle = do_sched_cfs_period_timer(cfs_b, overrun, cfsb_guard.flags);
> +		idle = do_sched_cfs_period_timer(cfs_b, overrun);
>  
>  		if (++count > 3) {
>  			u64 new, old = ktime_to_ns(cfs_b->period);