Re: [PATCH -rt] scheduling while atomic in fs/file.c

[Steven Rostedt <rostedt@goodmis.org>]

On Sun, 14 May 2006, Daniel Walker wrote:

> Quite the smp_processor_id() wanrings. I don't see any SMP
> concerns here . It just adds to a percpu list, so it shouldn't
> matter if it switches after sampling fdtable_defer_list .

I'm not so sure that there isn't SMP concerns here. I have to catch a
train in a few minutes, otherwise I would look deeper into this. But this
might be a candidate to turn fdtable_defer_list into a per_cpu_locked.

-- Steve

>
> Signed-Off-By: Daniel Walker <dwalker@mvista.com>
>
> Index: linux-2.6.16/fs/file.c
> ===================================================================
> --- linux-2.6.16.orig/fs/file.c
> +++ linux-2.6.16/fs/file.c
> @@ -138,6 +138,8 @@ static void free_fdtable_rcu(struct rcu_
>  		kfree(fdt);
>  	} else {
>  		fddef = &get_cpu_var(fdtable_defer_list);
> +		put_cpu_var(fdtable_defer_list);
> +
>  		spin_lock(&fddef->lock);
>  		fdt->next = fddef->next;
>  		fddef->next = fdt;
> @@ -149,7 +151,6 @@ static void free_fdtable_rcu(struct rcu_
>  		if (!schedule_work(&fddef->wq))
>  			mod_timer(&fddef->timer, 5);
>  		spin_unlock(&fddef->lock);
> -		put_cpu_var(fdtable_defer_list);
>  	}
>  }
>
> -
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