lkml.org 
[lkml]   [2004]   [May]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: scheduler: IRQs disabled over context switches
Ingo Molnar wrote:
> * Davide Libenzi <davidel@xmailserver.org> wrote:
>
>
>>We used to do it in 2.4. What changed to make it fragile? The
>>threading (TLS) thing?
>
>
> it _should_ work, but in the past we only had trouble from such changes
> (at least in the O(1) tree of scheduling - 2.4 scheduler is OK.). We
> could try the patch below. It certainly boots on SMP x86. But it causes
> a 3.5% slowdown in lat_ctx so i'd not do it unless there are some really
> good reasons.
>
> Ingo
>
> --- linux/kernel/sched.c.orig
> +++ linux/kernel/sched.c
> @@ -247,9 +247,15 @@ static DEFINE_PER_CPU(struct runqueue, r
> * Default context-switch locking:
> */
> #ifndef prepare_arch_switch
> -# define prepare_arch_switch(rq, next) do { } while (0)
> -# define finish_arch_switch(rq, next) spin_unlock_irq(&(rq)->lock)
> -# define task_running(rq, p) ((rq)->curr == (p))
> +# define prepare_arch_switch(rq, next) \
> + do { \
> + spin_lock(&(next)->switch_lock); \
> + spin_unlock(&(rq)->lock); \

spin_unlock_irq?
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:03    [W:0.059 / U:0.288 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site