* [PATCH net-next] net: speed up skb_rbtree_purge()
@ 2017-09-23 19:39 Eric Dumazet
2017-09-26 3:36 ` David Miller
0 siblings, 1 reply; 2+ messages in thread
From: Eric Dumazet @ 2017-09-23 19:39 UTC (permalink / raw)
To: David Miller; +Cc: netdev
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(-)
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);
+ }
}
/**
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net-next] net: speed up skb_rbtree_purge()
2017-09-23 19:39 [PATCH net-next] net: speed up skb_rbtree_purge() Eric Dumazet
@ 2017-09-26 3:36 ` David Miller
0 siblings, 0 replies; 2+ messages in thread
From: David Miller @ 2017-09-26 3:36 UTC (permalink / raw)
To: eric.dumazet; +Cc: netdev
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.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2017-09-23 19:39 [PATCH net-next] net: speed up skb_rbtree_purge() Eric Dumazet
2017-09-26 3:36 ` David Miller
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