[PATCH] x86: Allow percpu variables to be page-aligned

Let's allow page-alignment in general for per-cpu data (wanted by Xen, and
Ingo suggested KVM as well).

Because larger alignments can use more room, we increase the max per-cpu
memory to 64k rather than 32k: it's getting a little tight.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 2 insertions, 6 deletions

diff --git a/init/main.c b/init/main.c
index a92989e7836a..80f09f31bfab 100644
--- a/init/main.c
+++ b/init/main.c
@@ -369,12 +369,8 @@ static void __init setup_per_cpu_areas(void)
         unsigned long nr_possible_cpus = num_possible_cpus();
 
         /* Copy section for each CPU (we discard the original) */
-        size = ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES);
-#ifdef CONFIG_MODULES
-        if (size < PERCPU_ENOUGH_ROOM)
-                size = PERCPU_ENOUGH_ROOM;
-#endif
-        ptr = alloc_bootmem(size * nr_possible_cpus);
+        size = ALIGN(PERCPU_ENOUGH_ROOM, PAGE_SIZE);
+        ptr = alloc_bootmem_pages(size * nr_possible_cpus);
 
         for_each_possible_cpu(i) {
                 __per_cpu_offset[i] = ptr - __per_cpu_start;