net: speed up skb_rbtree_purge()

As measured in my prior patch ("sch_netem: faster rb tree removal"),
rbtree_postorder_for_each_entry_safe() is nice looking but much slower
than using rb_next() directly, except when tree is small enough
to fit in CPU caches (then the cost is the same)

Also note that there is not even an increase of text size :
$ size net/core/skbuff.o.before net/core/skbuff.o
   text	   data	    bss	    dec	    hex	filename
  40711	   1298	      0	  42009	   a419	net/core/skbuff.o.before
  40711	   1298	      0	  42009	   a419	net/core/skbuff.o

From: Eric Dumazet <edumazet@google.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2017-09-23 12:39:12 -07:00 committed by David S. Miller
parent 3aa605f28b
commit 7c90584c66
1 changed files with 7 additions and 4 deletions

View File

@ -2848,12 +2848,15 @@ EXPORT_SYMBOL(skb_queue_purge);
*/
void skb_rbtree_purge(struct rb_root *root)
{
struct sk_buff *skb, *next;
struct rb_node *p = rb_first(root);
rbtree_postorder_for_each_entry_safe(skb, next, root, rbnode)
while (p) {
struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);
p = rb_next(p);
rb_erase(&skb->rbnode, root);
kfree_skb(skb);
*root = RB_ROOT;
}
}
/**