[PATCH] Convert highest_possible_processor_id to nr_cpu_ids

We frequently need the maximum number of possible processors in order to
allocate arrays for all processors.  So far this was done using
highest_possible_processor_id().  However, we do need the number of
processors not the highest id.  Moreover the number was so far dynamically
calculated on each invokation.  The number of possible processors does not
change when the system is running.  We can therefore calculate that number
once.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Frederik Deweerdt <frederik.deweerdt@gmail.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

include/linux/cpumask.h

@@ -398,11 +398,11 @@ extern cpumask_t cpu_present_map;
 #endif
 
 #ifdef CONFIG_SMP
-int highest_possible_processor_id(void);
+extern int nr_cpu_ids;
 #define any_online_cpu(mask) __any_online_cpu(&(mask))
 int __any_online_cpu(const cpumask_t *mask);
 #else
-#define highest_possible_processor_id()	0
+#define nr_cpu_ids			1
 #define any_online_cpu(mask)		0
 #endif
 

init/main.c

@@ -387,14 +387,19 @@ static void __init setup_per_cpu_areas(void)
 /* Called by boot processor to activate the rest. */
 static void __init smp_init(void)
 {
-	unsigned int i;
+	unsigned int cpu;
+	unsigned highest = 0;
+
+	for_each_cpu_mask(cpu, cpu_possible_map)
+		highest = cpu;
+	nr_cpu_ids = highest + 1;
 
 	/* FIXME: This should be done in userspace --RR */
-	for_each_present_cpu(i) {
+	for_each_present_cpu(cpu) {
 		if (num_online_cpus() >= max_cpus)
 			break;
-		if (!cpu_online(i))
-			cpu_up(i);
+		if (!cpu_online(cpu))
+			cpu_up(cpu);
 	}
 
 	/* Any cleanup work */

lib/cpumask.c

@@ -15,22 +15,8 @@ int __next_cpu(int n, const cpumask_t *srcp)
 }
 EXPORT_SYMBOL(__next_cpu);
 
-/*
- * Find the highest possible smp_processor_id()
- *
- * Note: if we're prepared to assume that cpu_possible_map never changes
- * (reasonable) then this function should cache its return value.
- */
-int highest_possible_processor_id(void)
-{
-	unsigned int cpu;
-	unsigned highest = 0;
-
-	for_each_cpu_mask(cpu, cpu_possible_map)
-		highest = cpu;
-	return highest;
-}
-EXPORT_SYMBOL(highest_possible_processor_id);
+int nr_cpu_ids;
+EXPORT_SYMBOL(nr_cpu_ids);
 
 int __any_online_cpu(const cpumask_t *mask)
 {

net/bridge/netfilter/ebtables.c

@@ -833,8 +833,7 @@ static int translate_table(char *name, struct ebt_table_info *newinfo)
 		/* this will get free'd in do_replace()/ebt_register_table()
 		   if an error occurs */
 		newinfo->chainstack =
-			vmalloc((highest_possible_processor_id()+1)
-					* sizeof(*(newinfo->chainstack)));
+			vmalloc(nr_cpu_ids * sizeof(*(newinfo->chainstack)));
 		if (!newinfo->chainstack)
 			return -ENOMEM;
 		for_each_possible_cpu(i) {
@@ -947,8 +946,7 @@ static int do_replace(void __user *user, unsigned int len)
 	if (tmp.num_counters >= INT_MAX / sizeof(struct ebt_counter))
 		return -ENOMEM;
 
-	countersize = COUNTER_OFFSET(tmp.nentries) *
-					(highest_possible_processor_id()+1);
+	countersize = COUNTER_OFFSET(tmp.nentries) * nr_cpu_ids;
 	newinfo = vmalloc(sizeof(*newinfo) + countersize);
 	if (!newinfo)
 		return -ENOMEM;
@@ -1168,8 +1166,7 @@ int ebt_register_table(struct ebt_table *table)
 		return -EINVAL;
 	}
 
-	countersize = COUNTER_OFFSET(repl->nentries) *
-					(highest_possible_processor_id()+1);
+	countersize = COUNTER_OFFSET(repl->nentries) * nr_cpu_ids;
 	newinfo = vmalloc(sizeof(*newinfo) + countersize);
 	ret = -ENOMEM;
 	if (!newinfo)

net/sunrpc/svc.c

@@ -115,7 +115,7 @@ svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
 static int
 svc_pool_map_init_percpu(struct svc_pool_map *m)
 {
-	unsigned int maxpools = highest_possible_processor_id() + 1;
+	unsigned int maxpools = nr_cpu_ids;
 	unsigned int pidx = 0;
 	unsigned int cpu;
 	int err;