Messages in this thread Patch in this message | | | From | David Mosberger <> | Date | Wed, 9 Jul 2003 14:56:57 -0700 | Subject | Re: per_cpu fixes |
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>>>>> On Wed, 9 Jul 2003 14:20:29 -0700, David Mosberger <davidm@linux.hpl.hp.com> said:
David> Care needs to be taken when taking the address of a CPU-local David> variable, because otherwise things may break when comparing addresses David> on a platform which uses virtual remapping to implement such David> variables. In particular, it's almost always unsafe to use the David> address of a per-CPU variable which contains a "struct list", because David> the list-manipulation routines use the list-head address to detect the David> end of the list etc.
David> The patch below makes 2.5.74+ work on ia64 by reverting to the old David> definition of this_rq(). Ditto for kernel/timer.c.
Sorry, the original patch had an extraneous & which snuck in undetected.
Patch below should be better...
--david
===== kernel/sched.c 1.196 vs edited ===== --- 1.196/kernel/sched.c Wed Jul 9 11:06:25 2003 +++ edited/kernel/sched.c Wed Jul 9 14:36:55 2003 @@ -176,7 +176,7 @@ static DEFINE_PER_CPU(struct runqueue, runqueues); #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) -#define this_rq() (&__get_cpu_var(runqueues)) +#define this_rq() (cpu_rq(smp_processor_id())) /* not __get_cpu_var(runqueues)! */ #define task_rq(p) cpu_rq(task_cpu(p)) #define cpu_curr(cpu) (cpu_rq(cpu)->curr) #define rt_task(p) ((p)->prio < MAX_RT_PRIO) ===== kernel/timer.c 1.62 vs edited ===== --- 1.62/kernel/timer.c Wed Jul 9 11:06:25 2003 +++ edited/kernel/timer.c Wed Jul 9 13:30:31 2003 @@ -160,7 +160,7 @@ */ void add_timer(struct timer_list *timer) { - tvec_base_t *base = &get_cpu_var(tvec_bases); + tvec_base_t *base = &per_cpu(tvec_bases, get_cpu()); unsigned long flags; BUG_ON(timer_pending(timer) || !timer->function); @@ -171,7 +171,7 @@ internal_add_timer(base, timer); timer->base = base; spin_unlock_irqrestore(&base->lock, flags); - put_cpu_var(tvec_bases); + put_cpu(); } /*** @@ -234,7 +234,7 @@ return 1; spin_lock_irqsave(&timer->lock, flags); - new_base = &__get_cpu_var(tvec_bases); + new_base = &per_cpu(tvec_bases, smp_processor_id()); repeat: old_base = timer->base; @@ -792,7 +792,7 @@ */ static void run_timer_softirq(struct softirq_action *h) { - tvec_base_t *base = &__get_cpu_var(tvec_bases); + tvec_base_t *base = &per_cpu(tvec_bases, smp_processor_id()); if (time_after_eq(jiffies, base->timer_jiffies)) __run_timers(base); - 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/
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