SLUB: add support for dynamic cacheline size determination
SLUB currently assumes that the cacheline size is static. However, i386 f.e.
supports dynamic cache line size determination.
Use cache_line_size() instead of L1_CACHE_BYTES in the allocator.
That also explains the purpose of SLAB_HWCACHE_ALIGN. So we will need to keep
that one around to allow dynamic aligning of objects depending on boot
determination of the cache line size.
[akpm@linux-foundation.org: need to define it before we use it]
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/slub.c b/mm/slub.c
index 5db3da5..40e92d8 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -157,6 +157,11 @@
/* Internal SLUB flags */
#define __OBJECT_POISON 0x80000000 /* Poison object */
+/* Not all arches define cache_line_size */
+#ifndef cache_line_size
+#define cache_line_size() L1_CACHE_BYTES
+#endif
+
static int kmem_size = sizeof(struct kmem_cache);
#ifdef CONFIG_SMP
@@ -1480,8 +1485,8 @@
* then use it.
*/
if ((flags & SLAB_HWCACHE_ALIGN) &&
- size > L1_CACHE_BYTES / 2)
- return max_t(unsigned long, align, L1_CACHE_BYTES);
+ size > cache_line_size() / 2)
+ return max_t(unsigned long, align, cache_line_size());
if (align < ARCH_SLAB_MINALIGN)
return ARCH_SLAB_MINALIGN;
@@ -1667,8 +1672,8 @@
size += sizeof(void *);
/*
* Determine the alignment based on various parameters that the
- * user specified (this is unecessarily complex due to the attempt
- * to be compatible with SLAB. Should be cleaned up some day).
+ * user specified and the dynamic determination of cache line size
+ * on bootup.
*/
align = calculate_alignment(flags, align, s->objsize);
@@ -2280,7 +2285,7 @@
printk(KERN_INFO "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
" Processors=%d, Nodes=%d\n",
- KMALLOC_SHIFT_HIGH, L1_CACHE_BYTES,
+ KMALLOC_SHIFT_HIGH, cache_line_size(),
slub_min_order, slub_max_order, slub_min_objects,
nr_cpu_ids, nr_node_ids);
}