Re: [RFC PATCH 3/8] [NET]: uninline dev_alloc_skb, de-bloats a lot

Jan Engelhardt wrote:

On Feb 20 2008 15:47, Ilpo Järvinen wrote:

quoted

-23668  392 funcs, 104 +, 23772 -, diff: -23668 --- dev_alloc_skb

-static inline struct sk_buff *dev_alloc_skb(unsigned int length)
-{
-	return __dev_alloc_skb(length, GFP_ATOMIC);
-}
+extern struct sk_buff *dev_alloc_skb(unsigned int length);

Striking. How can this even happen? A callsite which calls

	dev_alloc_skb(n)

is just equivalent to

	__dev_alloc_skb(n, GFP_ATOMIC);

which means there's like 4 (or 8 if it's long) bytes more on the
stack. For a worst case, count in another 8 bytes for push and pop or mov on
the stack. But that still does not add up to 23 kb.

__dev_alloc_skb() is also an inline function which performs
some extra work. Which raises the question - if dev_alloc_skb()
is uninlined, shouldn't __dev_alloc_skb() be uninline as well?