[PATCH] Use Local Percpu Macros for Local Percpu Variables

In general, it is more better to use get_cpu_var() and __get_cpu_var()
to access per-cpu variables on this CPU than to use smp_processor_id()
and per_cpu().  In the current default implemention they are equivalent,
but on IA64 the former is already faster, and other archs will follow.

3 files changed, 6 insertions, 7 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 7dee095b31bd..367854d246ef 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -41,7 +41,7 @@ static void __unhash_process(struct task_struct *p)
 		detach_pid(p, PIDTYPE_PGID);
 		detach_pid(p, PIDTYPE_SID);
 		if (p->pid)
-			per_cpu(process_counts, smp_processor_id())--;
+			__get_cpu_var(process_counts)--;
 	}
 
 	REMOVE_LINKS(p);
diff --git a/kernel/fork.c b/kernel/fork.c
index 5ef2dca02354..2abbc9c2da23 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1006,7 +1006,7 @@ struct task_struct *copy_process(unsigned long clone_flags,
 		attach_pid(p, PIDTYPE_PGID, p->pgrp);
 		attach_pid(p, PIDTYPE_SID, p->session);
 		if (p->pid)
-			per_cpu(process_counts, smp_processor_id())++;
+			__get_cpu_var(process_counts)++;
 	} else
 		link_pid(p, p->pids + PIDTYPE_TGID, &p->group_leader->pids[PIDTYPE_TGID].pid);
 
diff --git a/kernel/timer.c b/kernel/timer.c
index ad3758c663d4..7bce7a7cb2c2 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -156,8 +156,7 @@ static void internal_add_timer(tvec_base_t *base, struct timer_list *timer)
  */
 void add_timer(struct timer_list *timer)
 {
-	int cpu = get_cpu();
-	tvec_base_t *base = &per_cpu(tvec_bases, cpu);
+	tvec_base_t *base = &get_cpu_var(tvec_bases);
   	unsigned long flags;
   
   	BUG_ON(timer_pending(timer) || !timer->function);
@@ -168,7 +167,7 @@ void add_timer(struct timer_list *timer)
 	internal_add_timer(base, timer);
 	timer->base = base;
 	spin_unlock_irqrestore(&base->lock, flags);
-	put_cpu();
+	put_cpu_var(tvec_bases);
 }
 
 /***
@@ -231,7 +230,7 @@ int mod_timer(struct timer_list *timer, unsigned long expires)
 		return 1;
 
 	spin_lock_irqsave(&timer->lock, flags);
-	new_base = &per_cpu(tvec_bases, smp_processor_id());
+	new_base = &__get_cpu_var(tvec_bases);
 repeat:
 	old_base = timer->base;
 
@@ -789,7 +788,7 @@ seqlock_t xtime_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED;
  */
 static void run_timer_softirq(struct softirq_action *h)
 {
-	tvec_base_t *base = &per_cpu(tvec_bases, smp_processor_id());
+	tvec_base_t *base = &__get_cpu_var(tvec_bases);
 
 	if (time_after_eq(jiffies, base->timer_jiffies))
 		__run_timers(base);