fq_codel: should use qdisc backlog as threshold

codel_should_drop() logic allows a packet being not dropped if queue
size is under max packet size.

In fq_codel, we have two possible backlogs : The qdisc global one, and
the flow local one.

The meaningful one for codel_should_drop() should be the global backlog,
not the per flow one, so that thin flows can have a non zero drop/mark
probability.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Dave Taht <dave.taht@bufferbloat.net>
Cc: Kathleen Nichols <nichols@pollere.com>
Cc: Van Jacobson <van@pollere.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet
2012-05-16 04:39:09 +00:00
committed by David S. Miller
parent c27b46e7f1
commit 865ec5523d
3 changed files with 12 additions and 12 deletions

View File

@@ -205,7 +205,7 @@ static codel_time_t codel_control_law(codel_time_t t,
static bool codel_should_drop(const struct sk_buff *skb,
unsigned int *backlog,
struct Qdisc *sch,
struct codel_vars *vars,
struct codel_params *params,
struct codel_stats *stats,
@@ -219,13 +219,13 @@ static bool codel_should_drop(const struct sk_buff *skb,
}
vars->ldelay = now - codel_get_enqueue_time(skb);
*backlog -= qdisc_pkt_len(skb);
sch->qstats.backlog -= qdisc_pkt_len(skb);
if (unlikely(qdisc_pkt_len(skb) > stats->maxpacket))
stats->maxpacket = qdisc_pkt_len(skb);
if (codel_time_before(vars->ldelay, params->target) ||
*backlog <= stats->maxpacket) {
sch->qstats.backlog <= stats->maxpacket) {
/* went below - stay below for at least interval */
vars->first_above_time = 0;
return false;
@@ -249,8 +249,7 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
struct codel_params *params,
struct codel_vars *vars,
struct codel_stats *stats,
codel_skb_dequeue_t dequeue_func,
u32 *backlog)
codel_skb_dequeue_t dequeue_func)
{
struct sk_buff *skb = dequeue_func(vars, sch);
codel_time_t now;
@@ -261,7 +260,7 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
return skb;
}
now = codel_get_time();
drop = codel_should_drop(skb, backlog, vars, params, stats, now);
drop = codel_should_drop(skb, sch, vars, params, stats, now);
if (vars->dropping) {
if (!drop) {
/* sojourn time below target - leave dropping state */
@@ -292,7 +291,7 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
qdisc_drop(skb, sch);
stats->drop_count++;
skb = dequeue_func(vars, sch);
if (!codel_should_drop(skb, backlog,
if (!codel_should_drop(skb, sch,
vars, params, stats, now)) {
/* leave dropping state */
vars->dropping = false;
@@ -313,7 +312,7 @@ static struct sk_buff *codel_dequeue(struct Qdisc *sch,
stats->drop_count++;
skb = dequeue_func(vars, sch);
drop = codel_should_drop(skb, backlog, vars, params,
drop = codel_should_drop(skb, sch, vars, params,
stats, now);
}
vars->dropping = true;