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

From: Jan Engelhardt
Date: Wed Feb 20 2008 - 11:36:01 EST



On Feb 20 2008 15:47, Ilpo JÃrvinen wrote:
>
>-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.
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