On 23/08/12 04:01, Tejun Heo wrote:

Hello, Sasha.

On Wed, Aug 22, 2012 at 04:26:56AM +0200, Sasha Levin wrote:

quoted

+#define DEFINE_HASHTABLE(name, bits)					\
+	struct hlist_head name[HASH_SIZE(bits)];

Shouldn't this be something like the following?

#define DEFINE_HASHTABLE(name, bits)					\
	struct hlist_head name[HASH_SIZE(bits)] =			\
		{ [0 ... HASH_SIZE(bits) - 1] = HLIST_HEAD_INIT };

Also, given that the declaration isn't non-trivial, you'll probably
want a matching DECLARE_HASHTABLE() macro too.

quoted

+/* Use hash_32 when possible to allow for fast 32bit hashing in 64bit kernels. */
+#define hash_min(val, bits) ((sizeof(val)==4) ? hash_32((val), (bits)) : hash_long((val), (bits)))

Why is the branching condition sizeof(val) == 4 instead of <= 4?
Also, no biggie but why isn't this macro in caps?

It should probably use gcc's statement expression extensions to prevent
side-effect issues with the arguments:

  #define hash_min ({		\
	sizeof(val) <= 4 ?	\
	hash_32(val, bits) :	\
	hash_long(val, bits));	\
  })

~Ryan

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>