Re: [patch] softirq performance fixes, cleanups, 2.4.10.

[Andrea Arcangeli]

On Fri, Sep 28, 2001 at 03:29:13AM +0400, Oleg Nesterov wrote:
> --- 2.4.10-softirq-A7/kernel/softirq.c.orig	Thu Sep 27 22:31:06 2001
> +++ 2.4.10-softirq-A7/kernel/softirq.c	Thu Sep 27 22:54:37 2001
> @@ -85,7 +85,7 @@
>  {
>  	int max_restart = MAX_SOFTIRQ_RESTART;
>  	int cpu = smp_processor_id();
> -	__u32 pending, mask;
> +	__u32 pending;
>  	long flags;
>  
>  	if (in_interrupt())
> @@ -98,7 +98,6 @@
>  	if (pending) {
>  		struct softirq_action *h;
>  
> -		mask = ~pending;
>  		local_bh_disable();
>  restart:
>  		/* Reset the pending bitmask before enabling irqs */

correct.

> @@ -381,26 +380,22 @@
>  #endif
>  
>  	current->nice = 19;
> -	schedule();
> -	__set_current_state(TASK_INTERRUPTIBLE);

buggy (check cpus_allowed).

>  	for (;;) {
> -back:
> +		schedule();
> +		__set_current_state(TASK_INTERRUPTIBLE);
> +
>  		do {
>  			do_softirq();
>  			if (current->need_resched)
>  				goto preempt;
>  		} while (softirq_pending(cpu));
> -		schedule();
> -		__set_current_state(TASK_INTERRUPTIBLE);
> -	}
>  
> +		continue;
>  preempt:
> -	__set_current_state(TASK_RUNNING);
> -	schedule();
> -	__set_current_state(TASK_INTERRUPTIBLE);
> -	goto back;
> +		__set_current_state(TASK_RUNNING);
> +	}
>  }

you dropped Ingo's optimization (but you resurrected the strictier /proc
statistics).

Andrea