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authorChristoph Lameter <cl@linux.com>2012-11-28 16:23:16 (GMT)
committerPekka Enberg <penberg@kernel.org>2012-12-11 10:14:28 (GMT)
commit4590685546a374fb0f60682ce0e3a6fd48911d46 (patch)
tree1287ce1e1633067f8bf2cf9f93f1d6fe8a1f8908 /mm/slab_common.c
parent2f9baa9fcf8d0a204ca129a671d6086cc100faab (diff)
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mm/sl[aou]b: Common alignment code
Extract the code to do object alignment from the allocators. Do the alignment calculations in slab_common so that the __kmem_cache_create functions of the allocators do not have to deal with alignment. Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Pekka Enberg <penberg@kernel.org>
Diffstat (limited to 'mm/slab_common.c')
-rw-r--r--mm/slab_common.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 497b45c..a8e76d7 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -73,6 +73,34 @@ static inline int kmem_cache_sanity_check(const char *name, size_t size)
#endif
/*
+ * 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 *));
+}
+
+
+/*
* kmem_cache_create - Create a cache.
* @name: A string which is used in /proc/slabinfo to identify this cache.
* @size: The size of objects to be created in this cache.
@@ -124,7 +152,7 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align
s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
if (s) {
s->object_size = s->size = size;
- s->align = align;
+ s->align = calculate_alignment(flags, align, size);
s->ctor = ctor;
s->name = kstrdup(name, GFP_KERNEL);
if (!s->name) {
@@ -211,7 +239,7 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t siz
s->name = name;
s->size = s->object_size = size;
- s->align = ARCH_KMALLOC_MINALIGN;
+ s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
err = __kmem_cache_create(s, flags);
if (err)