mm: only define hashdist variable when needed

For !CONFIG_NUMA, hashdist will always be 0, since it's setter is
otherwise compiled out.  So we can save 4 bytes of data and some .text
(although mostly in __init functions) by only defining it for
CONFIG_NUMA.

Signed-off-by: Rasmus Villemoes <[email protected]>
Acked-by: David Rientjes <[email protected]>
Reviewed-by: Michal Hocko <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/include/linux/bootmem.h b/include/linux/bootmem.h
index 0995c2de8162c2f6368647503ddda9017a68f6c6..f589222bfa87e457aa211469c22be8341450b6d5 100644 (file)
--- a/include/linux/bootmem.h
+++ b/include/linux/bootmem.h
@@ -357,12 +357,12 @@ extern void *alloc_large_system_hash(const char *tablename,
 /* Only NUMA needs hash distribution. 64bit NUMA architectures have
  * sufficient vmalloc space.
  */
-#if defined(CONFIG_NUMA) && defined(CONFIG_64BIT)
-#define HASHDIST_DEFAULT 1
+#ifdef CONFIG_NUMA
+#define HASHDIST_DEFAULT IS_ENABLED(CONFIG_64BIT)
+extern int hashdist;           /* Distribute hashes across NUMA nodes? */
 #else
-#define HASHDIST_DEFAULT 0
+#define hashdist (0)
 #endif
-extern int hashdist;           /* Distribute hashes across NUMA nodes? */
 
 
 #endif /* _LINUX_BOOTMEM_H */

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ebffa0e4a9c0451cfbd78bcf4835825ffd72c6de..159dbbc3375d66bf208bd778bf7c2a925a4e3fef 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6013,9 +6013,9 @@ out:
        return ret;
 }
 
+#ifdef CONFIG_NUMA
 int hashdist = HASHDIST_DEFAULT;
 
-#ifdef CONFIG_NUMA
 static int __init set_hashdist(char *str)
 {
        if (!str)