x86: convert cpuinfo_x86 array to a per_cpu array

cpu_data is currently an array defined using NR_CPUS.  This means that
we overallocate since we will rarely really use maximum configured cpus.
When NR_CPU count is raised to 4096 the size of cpu_data becomes
3,145,728 bytes.

These changes were adopted from the sparc64 (and ia64) code.  An
additional field was added to cpuinfo_x86 to be a non-ambiguous cpu
index.  This corresponds to the index into a cpumask_t as well as the
per_cpu index.  It's used in various places like show_cpuinfo().

cpu_data is defined to be the boot_cpu_data structure for the NON-SMP
case.

Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Dmitry Torokhov <dtor@mail.ru>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Mark M. Hoffman <mhoffman@lightlink.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 8 insertions, 3 deletions

diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 879a0f789b1e..2d42b414b777 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -85,12 +85,13 @@ static int show_cpuinfo(struct seq_file *m, void *v)
                 /* nothing */
         };
         struct cpuinfo_x86 *c = v;
-        int i, n = c - cpu_data;
+        int i, n = 0;
         int fpu_exception;
 
 #ifdef CONFIG_SMP
         if (!cpu_online(n))
                 return 0;
+        n = c->cpu_index;
 #endif
         seq_printf(m, "processor\t: %d\n"
                 "vendor_id\t: %s\n"
@@ -175,11 +176,15 @@ static int show_cpuinfo(struct seq_file *m, void *v)
 
 static void *c_start(struct seq_file *m, loff_t *pos)
 {
-        return *pos < NR_CPUS ? cpu_data + *pos : NULL;
+        if (*pos == 0)  /* just in case, cpu 0 is not the first */
+                *pos = first_cpu(cpu_possible_map);
+        if ((*pos) < NR_CPUS && cpu_possible(*pos))
+                return &cpu_data(*pos);
+        return NULL;
 }
 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
 {
-        ++*pos;
+        *pos = next_cpu(*pos, cpu_possible_map);
         return c_start(m, pos);
 }
 static void c_stop(struct seq_file *m, void *v)