On Sat, 2016-04-09 at 11:11 +0200, Jesper Dangaard Brouer wrote:
> Hi Eric,
> Above code is okay. But do you think we also can get away with the same
> trick we do with the SKB refcnf? Where we avoid an atomic operation if
> refcnt==1.
>
> void kfree_skb(struct sk_buff *skb)
> {
> if (unlikely(!skb))
> return;
> if (likely(atomic_read(&skb->users) == 1))
> smp_rmb();
> else if (likely(!atomic_dec_and_test(&skb->users)))
> return;
> trace_kfree_skb(skb, __builtin_return_address(0));
> __kfree_skb(skb);
> }
> EXPORT_SYMBOL(kfree_skb);
No we can not use this trick this for pages :
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ec91698360b3818ff426488a1529811f7a7ab87f
