[PATCH] mm/slab: make calculate_alignment() function static

Byongho Lee
2017-12-09T23:01:57Z

calculate_alignment() function is only used inside 'slab_common.c'.
So make it static and let compiler do more optimizations.

After this patch there's small improvements in 'text' and 'data' size.

$ gcc --version
gcc (GCC) 7.2.1 20171128

Before:
text data bss dec hex filename
9890457 3828702 1212364 14931523 e3d643 vmlinux

After:
text data bss dec hex filename
9890437 3828670 1212364 14931471 e3d60f vmlinux

Also I fixed a 'style problem' reported by 'scripts/checkpatch.pl'.

WARNING: Missing a blank line after declarations
#53: FILE: mm/slab_common.c:286:
+ unsigned long ralign = cache_line_size();
+ while (size <= ralign / 2)

Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
---
mm/slab.h | 3 ---
mm/slab_common.c | 56 +++++++++++++++++++++++++++++---------------------------
2 files changed, 29 insertions(+), 30 deletions(-)

diff --git a/mm/slab.h b/mm/slab.h
index 028cdc7df67e..e894889dc24a 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -79,9 +79,6 @@ extern const struct kmalloc_info_struct {
unsigned long size;
} kmalloc_info[];

-unsigned long calculate_alignment(unsigned long flags,
- unsigned long align, unsigned long size);
-
#ifndef CONFIG_SLOB
/* Kmalloc array related functions */
void setup_kmalloc_cache_index_table(void);
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 0d7fe71ff5e4..d25e7b56e20b 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -267,6 +267,35 @@ static inline void memcg_unlink_cache(struct kmem_cache *s)
}
#endif /* CONFIG_MEMCG && !CONFIG_SLOB */

+/*
+ * Figure out what the alignment of the objects will be given a set of
+ * flags, a user specified alignment and the size of the objects.
+ */
+static unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align, unsigned long size)
+{
+ /*
+ * If the user wants hardware cache aligned objects then follow that
+ * suggestion if the object is sufficiently large.
+ *
+ * The hardware cache alignment cannot override the specified
+ * alignment though. If that is greater then use it.
+ */
+ if (flags & SLAB_HWCACHE_ALIGN) {
+ unsigned long ralign;
+
+ ralign = cache_line_size();
+ while (size <= ralign / 2)
+ ralign /= 2;
+ align = max(align, ralign);
+ }
+
+ if (align < ARCH_SLAB_MINALIGN)
+ align = ARCH_SLAB_MINALIGN;
+
+ return ALIGN(align, sizeof(void *));
+}
+
/*
* Find a mergeable slab cache
*/
@@ -337,33 +366,6 @@ struct kmem_cache *find_mergeable(size_t size, size_t align,
return NULL;
}

-/*
- * Figure out what the alignment of the objects will be given a set of
- * flags, a user specified alignment and the size of the objects.
- */
-unsigned long calculate_alignment(unsigned long flags,
- unsigned long align, unsigned long size)
-{
- /*
- * If the user wants hardware cache aligned objects then follow that
- * suggestion if the object is sufficiently large.
- *
- * The hardware cache alignment cannot override the specified
- * alignment though. If that is greater then use it.
- */
- if (flags & SLAB_HWCACHE_ALIGN) {
- unsigned long ralign = cache_line_size();
- while (size <= ralign / 2)
- ralign /= 2;
- align = max(align, ralign);
- }
-
- if (align < ARCH_SLAB_MINALIGN)
- align = ARCH_SLAB_MINALIGN;
-
- return ALIGN(align, sizeof(void *));
-}
-
static struct kmem_cache *create_cache(const char *name,
size_t object_size, size_t size, size_t align,
unsigned long flags, void (*ctor)(void *),
--
2.15.1