slub: always align cpu_slab to honor cmpxchg_double requirement

[pandora-kernel.git] / include / linux / percpu.h

diff --git a/include/linux/percpu.h b/include/linux/percpu.h
index 8b97308..9ca008f 100644 (file)
--- a/include/linux/percpu.h
+++ b/include/linux/percpu.h
@@ -259,6 +259,9 @@ extern void __bad_size_call_parameter(void);
  * Special handling for cmpxchg_double.  cmpxchg_double is passed two
  * percpu variables.  The first has to be aligned to a double word
  * boundary and the second has to follow directly thereafter.
+ * We enforce this on all architectures even if they don't support
+ * a double cmpxchg instruction, since it's a cheap requirement, and it
+ * avoids breaking the requirement for architectures with the instruction.
  */
 #define __pcpu_double_call_return_bool(stem, pcp1, pcp2, ...)          \
 ({                                                                     \