On Tue, 16 Jan 2018, Matthew Wilcox wrote:

On Tue, Jan 16, 2018 at 12:17:01PM -0600, Christopher Lameter wrote:

quoted

Draft patch of how the data structs could change. kmem_cache_attr is read
only.

Looks good.  Although I would add Kees' user feature:

Sure I tried to do this quickly so that the basic struct changes are
visible.

And I'd start with
+struct kmem_cache *kmem_cache_create_attr(const kmem_cache_attr *);

leaving the old kmem_cache_create to kmalloc a kmem_cache_attr and
initialise it.

Well at some point we should convert the callers by putting the
definitions into const kmem_cache_attr initializations. That way
the callbacks function pointers are safe.

Can we also do something like this?

-#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
-		sizeof(struct __struct), __alignof__(struct __struct),\
-		(__flags), NULL)
+#define KMEM_CACHE(__struct, __flags) ({				\
+	const struct kmem_cache_attr kca ## __stringify(__struct) = {	\
+		.name = #__struct,					\
+		.size = sizeof(struct __struct),			\
+		.align = __alignof__(struct __struct),			\
+		.flags = (__flags),					\
+	};								\
+	kmem_cache_create_attr(&kca ## __stringify(__struct));		\
+})

That way we won't need to convert any of those users.

Yep thats what I was planning.