From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg Kroah-Hartman Subject: [PATCH 4.9 62/71] net: speed up skb_rbtree_purge() Date: Tue, 16 Oct 2018 19:09:59 +0200 Message-ID: <20181016170542.493641718@linuxfoundation.org> References: <20181016170539.315587743@linuxfoundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "David S. Miller" To: linux-kernel@vger.kernel.org, netdev@vger.kernel.org Return-path: In-Reply-To: <20181016170539.315587743@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet 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 Signed-off-by: David S. Miller (cherry picked from commit 7c90584c66cc4b033a3b684b0e0950f79e7b7166) Signed-off-by: Greg Kroah-Hartman --- net/core/skbuff.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -2433,12 +2433,15 @@ 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); + } } /**