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authorJesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>2018-11-15 02:26:33 +0100
committerDavid S. Miller <davem@davemloft.net>2018-11-17 05:39:34 +0100
commit09fd4860ea258d9666f852c213875e6bcdb1204e (patch)
tree6d76770738c3a02fbb7b9e4e1716887348abf383 /net/sched
parentetf: Cancel timer if there are no pending skbs (diff)
downloadlinux-09fd4860ea258d9666f852c213875e6bcdb1204e.tar.xz
linux-09fd4860ea258d9666f852c213875e6bcdb1204e.zip
etf: Use cached rb_root
ETF's peek() operation is heavily used so use an rb_root_cached instead and leverage rb_first_cached() which will run in O(1) instead of O(log n). Even if on 'timesortedlist_clear()' we could be using rb_erase(), we choose to use rb_erase_cached(), because if in the future we allow runtime changes to ETF parameters, and need to do a '_clear()', this might cause some hard to debug issues. Signed-off-by: Jesus Sanchez-Palencia <jesus.s.palencia@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
-rw-r--r--net/sched/sch_etf.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/net/sched/sch_etf.c b/net/sched/sch_etf.c
index fa85b24ac794..52452b546564 100644
--- a/net/sched/sch_etf.c
+++ b/net/sched/sch_etf.c
@@ -30,7 +30,7 @@ struct etf_sched_data {
int queue;
s32 delta; /* in ns */
ktime_t last; /* The txtime of the last skb sent to the netdevice. */
- struct rb_root head;
+ struct rb_root_cached head;
struct qdisc_watchdog watchdog;
ktime_t (*get_time)(void);
};
@@ -104,7 +104,7 @@ static struct sk_buff *etf_peek_timesortedlist(struct Qdisc *sch)
struct etf_sched_data *q = qdisc_priv(sch);
struct rb_node *p;
- p = rb_first(&q->head);
+ p = rb_first_cached(&q->head);
if (!p)
return NULL;
@@ -156,8 +156,9 @@ static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
struct sk_buff **to_free)
{
struct etf_sched_data *q = qdisc_priv(sch);
- struct rb_node **p = &q->head.rb_node, *parent = NULL;
+ struct rb_node **p = &q->head.rb_root.rb_node, *parent = NULL;
ktime_t txtime = nskb->tstamp;
+ bool leftmost = true;
if (!is_packet_valid(sch, nskb)) {
report_sock_error(nskb, EINVAL,
@@ -170,13 +171,15 @@ static int etf_enqueue_timesortedlist(struct sk_buff *nskb, struct Qdisc *sch,
parent = *p;
skb = rb_to_skb(parent);
- if (ktime_after(txtime, skb->tstamp))
+ if (ktime_after(txtime, skb->tstamp)) {
p = &parent->rb_right;
- else
+ leftmost = false;
+ } else {
p = &parent->rb_left;
+ }
}
rb_link_node(&nskb->rbnode, parent, p);
- rb_insert_color(&nskb->rbnode, &q->head);
+ rb_insert_color_cached(&nskb->rbnode, &q->head, leftmost);
qdisc_qstats_backlog_inc(sch, nskb);
sch->q.qlen++;
@@ -192,7 +195,7 @@ static void timesortedlist_erase(struct Qdisc *sch, struct sk_buff *skb,
{
struct etf_sched_data *q = qdisc_priv(sch);
- rb_erase(&skb->rbnode, &q->head);
+ rb_erase_cached(&skb->rbnode, &q->head);
/* The rbnode field in the skb re-uses these fields, now that
* we are done with the rbnode, reset them.
@@ -388,14 +391,14 @@ static int etf_init(struct Qdisc *sch, struct nlattr *opt,
static void timesortedlist_clear(struct Qdisc *sch)
{
struct etf_sched_data *q = qdisc_priv(sch);
- struct rb_node *p = rb_first(&q->head);
+ struct rb_node *p = rb_first_cached(&q->head);
while (p) {
struct sk_buff *skb = rb_to_skb(p);
p = rb_next(p);
- rb_erase(&skb->rbnode, &q->head);
+ rb_erase_cached(&skb->rbnode, &q->head);
rtnl_kfree_skbs(skb, skb);
sch->q.qlen--;
}