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authorEric Dumazet <edumazet@google.com>2016-06-14 06:21:50 +0300
committerDavid S. Miller <davem@davemloft.net>2016-06-16 00:08:34 +0300
commit1b5c5493e3e68181be344cb51bf9df192d05ffc2 (patch)
tree9c0f004d07c1fe3314b155695a93f2de51a315c6 /net
parent35c55c9877f8de0ab129fa1a309271d0ecc868b9 (diff)
downloadlinux-1b5c5493e3e68181be344cb51bf9df192d05ffc2.tar.xz
net_sched: add the ability to defer skb freeing
qdisc are changed under RTNL protection and often while blocking BH and root qdisc spinlock. When lots of skbs need to be dropped, we free them under these locks causing TX/RX freezes, and more generally latency spikes. This commit adds rtnl_kfree_skbs(), used to queue skbs for deferred freeing. Actual freeing happens right after RTNL is released, with appropriate scheduling points. rtnl_qdisc_drop() can also be used in place of disc_drop() when RTNL is held. qdisc_reset_queue() and __qdisc_reset_queue() get the new behavior, so standard qdiscs like pfifo, pfifo_fast... have their ->reset() method automatically handled. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/rtnetlink.c22
-rw-r--r--net/sched/sch_generic.c2
2 files changed, 23 insertions, 1 deletions
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index d69c4644f8f2..eb49ca24274a 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -71,9 +71,31 @@ void rtnl_lock(void)
}
EXPORT_SYMBOL(rtnl_lock);
+static struct sk_buff *defer_kfree_skb_list;
+void rtnl_kfree_skbs(struct sk_buff *head, struct sk_buff *tail)
+{
+ if (head && tail) {
+ tail->next = defer_kfree_skb_list;
+ defer_kfree_skb_list = head;
+ }
+}
+EXPORT_SYMBOL(rtnl_kfree_skbs);
+
void __rtnl_unlock(void)
{
+ struct sk_buff *head = defer_kfree_skb_list;
+
+ defer_kfree_skb_list = NULL;
+
mutex_unlock(&rtnl_mutex);
+
+ while (head) {
+ struct sk_buff *next = head->next;
+
+ kfree_skb(head);
+ cond_resched();
+ head = next;
+ }
}
void rtnl_unlock(void)
diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 0c9cb516f2e3..773b632e1e33 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -493,7 +493,7 @@ static void pfifo_fast_reset(struct Qdisc *qdisc)
struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
for (prio = 0; prio < PFIFO_FAST_BANDS; prio++)
- __qdisc_reset_queue(qdisc, band2list(priv, prio));
+ __qdisc_reset_queue(band2list(priv, prio));
priv->bitmap = 0;
qdisc->qstats.backlog = 0;