| From foo@baz Mon Sep 17 13:33:56 CEST 2018 |
| From: Stephen Hemminger <stephen@networkplumber.org> |
| Date: Thu, 13 Sep 2018 07:58:53 -0700 |
| Subject: net: speed up skb_rbtree_purge() |
| To: davem@davemloft.net, gregkh@linuxfoundation.org |
| Cc: netdev@vger.kernel.org, stable@vger.kernel.org, edumazet@google.com |
| Message-ID: <20180913145902.17531-22-sthemmin@microsoft.com> |
| |
| 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> |
| |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| (cherry picked from commit 7c90584c66cc4b033a3b684b0e0950f79e7b7166) |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/core/skbuff.c | 11 +++++++---- |
| 1 file changed, 7 insertions(+), 4 deletions(-) |
| |
| --- a/net/core/skbuff.c |
| +++ b/net/core/skbuff.c |
| @@ -2850,12 +2850,15 @@ 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); |
| + } |
| } |
| |
| /** |
