linux-kernel - Re: [patch V2 4/9] softirq: Make softirq control and processing RT aware

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Date:   Tue, 8 Dec 2020 01:08:54 +0100
From:   Frederic Weisbecker <frederic@...nel.org>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Paul McKenney <paulmck@...nel.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: Re: [patch V2 4/9] softirq: Make softirq control and processing RT
 aware

On Fri, Dec 04, 2020 at 06:01:55PM +0100, Thomas Gleixner wrote:
> +static void __local_bh_enable(unsigned int cnt, bool unlock)
> +{
> +	unsigned long flags;
> +	int newcnt;
> +
> +	DEBUG_LOCKS_WARN_ON(current->softirq_disable_cnt !=
> +			    this_cpu_read(softirq_ctrl.cnt));

Less important since it's debug code, but still can be __this_cpu_read().

> +
> +	if (IS_ENABLED(CONFIG_TRACE_IRQFLAGS) && softirq_count() == cnt) {
> +		raw_local_irq_save(flags);
> +		lockdep_softirqs_on(_RET_IP_);
> +		raw_local_irq_restore(flags);
> +	}
> +
> +	newcnt = __this_cpu_sub_return(softirq_ctrl.cnt, cnt);
> +	current->softirq_disable_cnt = newcnt;
> +
> +	if (!newcnt && unlock) {
> +		rcu_read_unlock();
> +		local_unlock(&softirq_ctrl.lock);
> +	}
> +}
> +
> +static inline bool should_wake_ksoftirqd(void)
> +{
> +	return !this_cpu_read(softirq_ctrl.cnt);

And that too.

Other than these boring details:

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

Thanks.