Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266123AbTGIVFy (ORCPT ); Wed, 9 Jul 2003 17:05:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266141AbTGIVFx (ORCPT ); Wed, 9 Jul 2003 17:05:53 -0400 Received: from palrel13.hp.com ([156.153.255.238]:54485 "EHLO palrel13.hp.com") by vger.kernel.org with ESMTP id S266123AbTGIVFw (ORCPT ); Wed, 9 Jul 2003 17:05:52 -0400 Date: Wed, 9 Jul 2003 14:20:29 -0700 From: David Mosberger Message-Id: <200307092120.h69LKTBH002759@napali.hpl.hp.com> To: rusty@rustcorp.com.au Cc: linux-kernel@vger.kernel.org Subject: per_cpu fixes X-URL: http://www.hpl.hp.com/personal/David_Mosberger/ Reply-To: davidm@hpl.hp.com Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2394 Lines: 71 Rusty, Care needs to be taken when taking the address of a CPU-local variable, because otherwise things may break when comparing addresses on a platform which uses virtual remapping to implement such variables. In particular, it's almost always unsafe to use the address of a per-CPU variable which contains a "struct list", because the list-manipulation routines use the list-head address to detect the end of the list etc. The patch below makes 2.5.74+ work on ia64 by reverting to the old definition of this_rq(). Ditto for kernel/timer.c. --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 14:06:49 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/