diff options
| author | Petr Machata <petrm@mellanox.com> | 2020-03-13 01:10:57 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-03-14 21:03:46 -0700 |
| commit | 0a7fad2376ba6b37c6b1a1072ed2a2381d82cd18 (patch) | |
| tree | cecaf961e1015055ee4f9912de73fbd5d04f0722 /net/sched | |
| parent | 14bc175d9c885c86239de3d730eea85ad67bfe7b (diff) | |
net: sched: RED: Introduce an ECN nodrop mode
When the RED Qdisc is currently configured to enable ECN, the RED algorithm
is used to decide whether a certain SKB should be marked. If that SKB is
not ECN-capable, it is early-dropped.
It is also possible to keep all traffic in the queue, and just mark the
ECN-capable subset of it, as appropriate under the RED algorithm. Some
switches support this mode, and some installations make use of it.
To that end, add a new RED flag, TC_RED_NODROP. When the Qdisc is
configured with this flag, non-ECT traffic is enqueued instead of being
early-dropped.
Signed-off-by: Petr Machata <petrm@mellanox.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/sch_red.c | 31 |
1 files changed, 25 insertions, 6 deletions
diff --git a/net/sched/sch_red.c b/net/sched/sch_red.c index d4ce111704dc..3ef0a4f7399b 100644 --- a/net/sched/sch_red.c +++ b/net/sched/sch_red.c @@ -48,7 +48,7 @@ struct red_sched_data { struct Qdisc *qdisc; }; -static const u32 red_supported_flags = TC_RED_HISTORIC_FLAGS; +static const u32 red_supported_flags = TC_RED_HISTORIC_FLAGS | TC_RED_NODROP; static inline int red_use_ecn(struct red_sched_data *q) { @@ -60,6 +60,11 @@ static inline int red_use_harddrop(struct red_sched_data *q) return q->flags & TC_RED_HARDDROP; } +static int red_use_nodrop(struct red_sched_data *q) +{ + return q->flags & TC_RED_NODROP; +} + static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch, struct sk_buff **to_free) { @@ -80,23 +85,36 @@ static int red_enqueue(struct sk_buff *skb, struct Qdisc *sch, case RED_PROB_MARK: qdisc_qstats_overlimit(sch); - if (!red_use_ecn(q) || !INET_ECN_set_ce(skb)) { + if (!red_use_ecn(q)) { q->stats.prob_drop++; goto congestion_drop; } - q->stats.prob_mark++; + if (INET_ECN_set_ce(skb)) { + q->stats.prob_mark++; + } else if (!red_use_nodrop(q)) { + q->stats.prob_drop++; + goto congestion_drop; + } + + /* Non-ECT packet in ECN nodrop mode: queue it. */ break; case RED_HARD_MARK: qdisc_qstats_overlimit(sch); - if (red_use_harddrop(q) || !red_use_ecn(q) || - !INET_ECN_set_ce(skb)) { + if (red_use_harddrop(q) || !red_use_ecn(q)) { + q->stats.forced_drop++; + goto congestion_drop; + } + + if (INET_ECN_set_ce(skb)) { + q->stats.forced_mark++; + } else if (!red_use_nodrop(q)) { q->stats.forced_drop++; goto congestion_drop; } - q->stats.forced_mark++; + /* Non-ECT packet in ECN nodrop mode: queue it. */ break; } @@ -171,6 +189,7 @@ static int red_offload(struct Qdisc *sch, bool enable) opt.set.limit = q->limit; opt.set.is_ecn = red_use_ecn(q); opt.set.is_harddrop = red_use_harddrop(q); + opt.set.is_nodrop = red_use_nodrop(q); opt.set.qstats = &sch->qstats; } else { opt.command = TC_RED_DESTROY; |