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authorDavid S. Miller <davem@davemloft.net>2016-06-15 14:08:36 -0700
committerDavid S. Miller <davem@davemloft.net>2016-06-15 14:08:36 -0700
commit88da48f4977a4b31e03cac1b6ea38f24d7916d10 (patch)
tree462e30cb64cf066c1d13cd98eb0ea502115bafda
parent35c55c9877f8de0ab129fa1a309271d0ecc868b9 (diff)
parentfea024784f588a1c50e7718d6053697ebdcc033e (diff)
downloadlinux-stericsson-88da48f4977a4b31e03cac1b6ea38f24d7916d10.tar.gz
Merge branch 'sched_skb_free_defer'
Eric Dumazet says: ==================== net_sched: defer skb freeing while changing qdiscs qdiscs/classes 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. I saw spikes of 50+ ms on quite fast hardware... This patch series adds a simple queue protected by RTNL where skbs can be placed until RTNL is released. Note that this might also serve in the future for optional reinjection of packets when a qdisc is replaced. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--include/linux/rtnetlink.h5
-rw-r--r--include/net/sch_generic.h16
-rw-r--r--net/core/rtnetlink.c22
-rw-r--r--net/sched/sch_choke.c8
-rw-r--r--net/sched/sch_codel.c2
-rw-r--r--net/sched/sch_fq.c19
-rw-r--r--net/sched/sch_fq_codel.c17
-rw-r--r--net/sched/sch_generic.c2
-rw-r--r--net/sched/sch_hhf.c4
-rw-r--r--net/sched/sch_htb.c4
-rw-r--r--net/sched/sch_netem.c4
-rw-r--r--net/sched/sch_pie.c2
-rw-r--r--net/sched/sch_sfq.c2
13 files changed, 72 insertions, 35 deletions
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index c006cc900c44..2daece8979f7 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -89,8 +89,9 @@ void net_inc_egress_queue(void);
void net_dec_egress_queue(void);
#endif
-extern void rtnetlink_init(void);
-extern void __rtnl_unlock(void);
+void rtnetlink_init(void);
+void __rtnl_unlock(void);
+void rtnl_kfree_skbs(struct sk_buff *head, struct sk_buff *tail);
#define ASSERT_RTNL() do { \
if (unlikely(!rtnl_is_locked())) { \
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index 9a0d177884c6..4f7cee8344c4 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -683,19 +683,21 @@ static inline struct sk_buff *qdisc_dequeue_peeked(struct Qdisc *sch)
return skb;
}
-static inline void __qdisc_reset_queue(struct Qdisc *sch,
- struct sk_buff_head *list)
+static inline void __qdisc_reset_queue(struct sk_buff_head *list)
{
/*
* We do not know the backlog in bytes of this list, it
* is up to the caller to correct it
*/
- __skb_queue_purge(list);
+ if (!skb_queue_empty(list)) {
+ rtnl_kfree_skbs(list->next, list->prev);
+ __skb_queue_head_init(list);
+ }
}
static inline void qdisc_reset_queue(struct Qdisc *sch)
{
- __qdisc_reset_queue(sch, &sch->q);
+ __qdisc_reset_queue(&sch->q);
sch->qstats.backlog = 0;
}
@@ -716,6 +718,12 @@ static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
return old;
}
+static inline void rtnl_qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
+{
+ rtnl_kfree_skbs(skb, skb);
+ qdisc_qstats_drop(sch);
+}
+
static inline int qdisc_drop(struct sk_buff *skb, struct Qdisc *sch)
{
kfree_skb(skb);
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_choke.c b/net/sched/sch_choke.c
index 04e0b0583e00..789b69ee9e51 100644
--- a/net/sched/sch_choke.c
+++ b/net/sched/sch_choke.c
@@ -375,11 +375,11 @@ static void choke_reset(struct Qdisc *sch)
q->head = (q->head + 1) & q->tab_mask;
if (!skb)
continue;
- qdisc_qstats_backlog_dec(sch, skb);
- --sch->q.qlen;
- qdisc_drop(skb, sch);
+ rtnl_qdisc_drop(skb, sch);
}
+ sch->q.qlen = 0;
+ sch->qstats.backlog = 0;
memset(q->tab, 0, (q->tab_mask + 1) * sizeof(struct sk_buff *));
q->head = q->tail = 0;
red_restart(&q->vars);
@@ -455,7 +455,7 @@ static int choke_change(struct Qdisc *sch, struct nlattr *opt)
dropped += qdisc_pkt_len(skb);
qdisc_qstats_backlog_dec(sch, skb);
--sch->q.qlen;
- qdisc_drop(skb, sch);
+ rtnl_qdisc_drop(skb, sch);
}
qdisc_tree_reduce_backlog(sch, oqlen - sch->q.qlen, dropped);
q->head = 0;
diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c
index dddf3bb65a32..c5bc424e3b3c 100644
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -174,7 +174,7 @@ static int codel_change(struct Qdisc *sch, struct nlattr *opt)
dropped += qdisc_pkt_len(skb);
qdisc_qstats_backlog_dec(sch, skb);
- qdisc_drop(skb, sch);
+ rtnl_qdisc_drop(skb, sch);
}
qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);
diff --git a/net/sched/sch_fq.c b/net/sched/sch_fq.c
index f49c81e91acd..6eb06674f778 100644
--- a/net/sched/sch_fq.c
+++ b/net/sched/sch_fq.c
@@ -514,17 +514,25 @@ out:
return skb;
}
+static void fq_flow_purge(struct fq_flow *flow)
+{
+ rtnl_kfree_skbs(flow->head, flow->tail);
+ flow->head = NULL;
+ flow->qlen = 0;
+}
+
static void fq_reset(struct Qdisc *sch)
{
struct fq_sched_data *q = qdisc_priv(sch);
struct rb_root *root;
- struct sk_buff *skb;
struct rb_node *p;
struct fq_flow *f;
unsigned int idx;
- while ((skb = fq_dequeue_head(sch, &q->internal)) != NULL)
- kfree_skb(skb);
+ sch->q.qlen = 0;
+ sch->qstats.backlog = 0;
+
+ fq_flow_purge(&q->internal);
if (!q->fq_root)
return;
@@ -535,8 +543,7 @@ static void fq_reset(struct Qdisc *sch)
f = container_of(p, struct fq_flow, fq_node);
rb_erase(p, root);
- while ((skb = fq_dequeue_head(sch, f)) != NULL)
- kfree_skb(skb);
+ fq_flow_purge(f);
kmem_cache_free(fq_flow_cachep, f);
}
@@ -737,7 +744,7 @@ static int fq_change(struct Qdisc *sch, struct nlattr *opt)
if (!skb)
break;
drop_len += qdisc_pkt_len(skb);
- kfree_skb(skb);
+ rtnl_kfree_skbs(skb, skb);
drop_count++;
}
qdisc_tree_reduce_backlog(sch, drop_count, drop_len);
diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c
index a302e8ef5498..2dc0a849515a 100644
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -336,6 +336,12 @@ begin:
return skb;
}
+static void fq_codel_flow_purge(struct fq_codel_flow *flow)
+{
+ rtnl_kfree_skbs(flow->head, flow->tail);
+ flow->head = NULL;
+}
+
static void fq_codel_reset(struct Qdisc *sch)
{
struct fq_codel_sched_data *q = qdisc_priv(sch);
@@ -346,18 +352,13 @@ static void fq_codel_reset(struct Qdisc *sch)
for (i = 0; i < q->flows_cnt; i++) {
struct fq_codel_flow *flow = q->flows + i;
- while (flow->head) {
- struct sk_buff *skb = dequeue_head(flow);
-
- qdisc_qstats_backlog_dec(sch, skb);
- kfree_skb(skb);
- }
-
+ fq_codel_flow_purge(flow);
INIT_LIST_HEAD(&flow->flowchain);
codel_vars_init(&flow->cvars);
}
memset(q->backlogs, 0, q->flows_cnt * sizeof(u32));
sch->q.qlen = 0;
+ sch->qstats.backlog = 0;
q->memory_usage = 0;
}
@@ -433,7 +434,7 @@ static int fq_codel_change(struct Qdisc *sch, struct nlattr *opt)
struct sk_buff *skb = fq_codel_dequeue(sch);
q->cstats.drop_len += qdisc_pkt_len(skb);
- kfree_skb(skb);
+ rtnl_kfree_skbs(skb, skb);
q->cstats.drop_count++;
}
qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, q->cstats.drop_len);
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;
diff --git a/net/sched/sch_hhf.c b/net/sched/sch_hhf.c
index c51791848a38..c44593b8e65a 100644
--- a/net/sched/sch_hhf.c
+++ b/net/sched/sch_hhf.c
@@ -464,7 +464,7 @@ static void hhf_reset(struct Qdisc *sch)
struct sk_buff *skb;
while ((skb = hhf_dequeue(sch)) != NULL)
- kfree_skb(skb);
+ rtnl_kfree_skbs(skb, skb);
}
static void *hhf_zalloc(size_t sz)
@@ -574,7 +574,7 @@ static int hhf_change(struct Qdisc *sch, struct nlattr *opt)
while (sch->q.qlen > sch->limit) {
struct sk_buff *skb = hhf_dequeue(sch);
- kfree_skb(skb);
+ rtnl_kfree_skbs(skb, skb);
}
qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen,
prev_backlog - sch->qstats.backlog);
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 07dcd2933f01..a454605ab5cb 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -957,7 +957,7 @@ static void htb_reset(struct Qdisc *sch)
}
}
qdisc_watchdog_cancel(&q->watchdog);
- __skb_queue_purge(&q->direct_queue);
+ __qdisc_reset_queue(&q->direct_queue);
sch->q.qlen = 0;
sch->qstats.backlog = 0;
memset(q->hlevel, 0, sizeof(q->hlevel));
@@ -1231,7 +1231,7 @@ static void htb_destroy(struct Qdisc *sch)
htb_destroy_class(sch, cl);
}
qdisc_class_hash_destroy(&q->clhash);
- __skb_queue_purge(&q->direct_queue);
+ __qdisc_reset_queue(&q->direct_queue);
}
static int htb_delete(struct Qdisc *sch, unsigned long arg)
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 876df13c745a..e271967439bf 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -368,9 +368,7 @@ static void tfifo_reset(struct Qdisc *sch)
struct sk_buff *skb = netem_rb_to_skb(p);
rb_erase(p, &q->t_root);
- skb->next = NULL;
- skb->prev = NULL;
- kfree_skb(skb);
+ rtnl_kfree_skbs(skb, skb);
}
}
diff --git a/net/sched/sch_pie.c b/net/sched/sch_pie.c
index 71ae3b9629f9..912a46a5d02e 100644
--- a/net/sched/sch_pie.c
+++ b/net/sched/sch_pie.c
@@ -234,7 +234,7 @@ static int pie_change(struct Qdisc *sch, struct nlattr *opt)
dropped += qdisc_pkt_len(skb);
qdisc_qstats_backlog_dec(sch, skb);
- qdisc_drop(skb, sch);
+ rtnl_qdisc_drop(skb, sch);
}
qdisc_tree_reduce_backlog(sch, qlen - sch->q.qlen, dropped);
diff --git a/net/sched/sch_sfq.c b/net/sched/sch_sfq.c
index a2e0b855d1c8..57d118b41cad 100644
--- a/net/sched/sch_sfq.c
+++ b/net/sched/sch_sfq.c
@@ -520,7 +520,7 @@ sfq_reset(struct Qdisc *sch)
struct sk_buff *skb;
while ((skb = sfq_dequeue(sch)) != NULL)
- kfree_skb(skb);
+ rtnl_kfree_skbs(skb, skb);
}
/*