diff mbox series

[net-next] net: speed up skb_rbtree_purge()

Message ID 1506195552.29839.214.camel@edumazet-glaptop3.roam.corp.google.com
State Accepted, archived
Delegated to: David Miller
Headers show
Series [net-next] net: speed up skb_rbtree_purge() | expand

Commit Message

Eric Dumazet Sept. 23, 2017, 7:39 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

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>
---
 net/core/skbuff.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

Comments

David Miller Sept. 26, 2017, 3:36 a.m. UTC | #1 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 23 Sep 2017 12:39:12 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> 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>

Applied.
diff mbox series

Patch

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 16982de649b97b92423a4f9f5eac1e98ca803370..000ce735fa8d649e7abeeef2ebab8501dea96efd 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -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);
+	}
 }
 
 /**