Commit 7c90584c authored Sep 23, 2017 by Eric Dumazet Committed by David S. Miller Sep 25, 2017

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>

parent 3aa605f2

net/core/skbuff.c

+7 −4

Original line number	Diff line number	Diff line
		@@ -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)
		kfree_skb(skb);
		while (p) {
		struct sk_buff *skb = rb_entry(p, struct sk_buff, rbnode);

		*root = RB_ROOT;
		p = rb_next(p);
		rb_erase(&skb->rbnode, root);
		kfree_skb(skb);
		}
		}

		/**