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Subject[PATCH 1/2] init: move setup of nr_cpu_ids to as early as possible
Move the setting of nr_cpu_ids from sched_init() to start_kernel()
so that it's available as early as possible.

Note that an arch has the option of setting it even earlier if need be,
but it should not result in a different value than the setup_nr_cpu_ids()
function.

Based on:
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
git://git.kernel.org/pub/scm/linux/kernel/git/x86/linux-2.6-x86.git

Signed-off-by: Mike Travis <travis@sgi.com>
---
init/main.c | 17 +++++++++++++++++
kernel/sched.c | 7 -------
2 files changed, 17 insertions(+), 7 deletions(-)

--- linux-2.6.orig/init/main.c
+++ linux-2.6/init/main.c
@@ -360,10 +360,26 @@ static void __init smp_init(void)
#endif

static inline void setup_per_cpu_areas(void) { }
+static inline void setup_nr_cpu_ids(void) { }
static inline void smp_prepare_cpus(unsigned int maxcpus) { }

#else

+/* Setup number of possible processor ids */
+int nr_cpu_ids __read_mostly = NR_CPUS;
+EXPORT_SYMBOL(nr_cpu_ids);
+
+/* An arch may set nr_cpu_ids earlier if needed, so this would be redundant */
+static void __init setup_nr_cpu_ids(void)
+{
+ int cpu, highest_cpu = 0;
+
+ for_each_possible_cpu(cpu)
+ highest_cpu = cpu;
+
+ nr_cpu_ids = highest_cpu + 1;
+}
+
#ifndef CONFIG_HAVE_SETUP_PER_CPU_AREA
unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;

@@ -544,6 +560,7 @@ asmlinkage void __init start_kernel(void
setup_command_line(command_line);
unwind_setup();
setup_per_cpu_areas();
+ setup_nr_cpu_ids();
smp_prepare_boot_cpu(); /* arch-specific boot-cpu hooks */

/*
--- linux-2.6.orig/kernel/sched.c
+++ linux-2.6/kernel/sched.c
@@ -6229,10 +6229,6 @@ void __init migration_init(void)

#ifdef CONFIG_SMP

-/* Number of possible processor ids */
-int nr_cpu_ids __read_mostly = NR_CPUS;
-EXPORT_SYMBOL(nr_cpu_ids);
-
#ifdef CONFIG_SCHED_DEBUG

static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level)
@@ -7443,7 +7439,6 @@ static void init_tg_rt_entry(struct rq *

void __init sched_init(void)
{
- int highest_cpu = 0;
int i, j;

#ifdef CONFIG_SMP
@@ -7505,7 +7500,6 @@ void __init sched_init(void)
#endif
init_rq_hrtick(rq);
atomic_set(&rq->nr_iowait, 0);
- highest_cpu = i;
}

set_load_weight(&init_task);
@@ -7515,7 +7509,6 @@ void __init sched_init(void)
#endif

#ifdef CONFIG_SMP
- nr_cpu_ids = highest_cpu + 1;
open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
#endif

--


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