From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: [RFC PATCH 11/13] net: sched: pfifo_fast use alf_queue Date: Wed, 17 Aug 2016 12:38:10 -0700 Message-ID: <20160817193810.27032.27544.stgit@john-Precision-Tower-5810> References: <20160817193120.27032.20918.stgit@john-Precision-Tower-5810> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: john.r.fastabend@intel.com, netdev@vger.kernel.org, john.fastabend@gmail.com, davem@davemloft.net To: xiyou.wangcong@gmail.com, jhs@mojatatu.com, alexei.starovoitov@gmail.com, eric.dumazet@gmail.com, brouer@redhat.com Return-path: Received: from mail-oi0-f66.google.com ([209.85.218.66]:35158 "EHLO mail-oi0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752761AbcHQTid (ORCPT ); Wed, 17 Aug 2016 15:38:33 -0400 Received: by mail-oi0-f66.google.com with SMTP id e80so13014296oig.2 for ; Wed, 17 Aug 2016 12:38:32 -0700 (PDT) In-Reply-To: <20160817193120.27032.20918.stgit@john-Precision-Tower-5810> Sender: netdev-owner@vger.kernel.org List-ID: This converts the pfifo_fast qdisc to use the alf_queue enqueue and dequeue routines then sets the NOLOCK bit. This also removes the logic used to pick the next band to dequeue from and instead just checks each alf_queue for packets from top priority to lowest. This might need to be a bit more clever but seems to work for now. Signed-off-by: John Fastabend --- net/sched/sch_generic.c | 133 +++++++++++++++++++++++++++-------------------- 1 file changed, 77 insertions(+), 56 deletions(-) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index f5b7254..c41a5dd 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -26,6 +26,7 @@ #include #include #include +#include #include #include #include @@ -555,88 +556,79 @@ static const u8 prio2band[TC_PRIO_MAX + 1] = { /* * Private data for a pfifo_fast scheduler containing: - * - queues for the three band - * - bitmap indicating which of the bands contain skbs + * - rings for priority bands */ struct pfifo_fast_priv { - u32 bitmap; - struct sk_buff_head q[PFIFO_FAST_BANDS]; + struct skb_array q[PFIFO_FAST_BANDS]; }; -/* - * Convert a bitmap to the first band number where an skb is queued, where: - * bitmap=0 means there are no skbs on any band. - * bitmap=1 means there is an skb on band 0. - * bitmap=7 means there are skbs on all 3 bands, etc. - */ -static const int bitmap2band[] = {-1, 0, 1, 0, 2, 0, 1, 0}; - -static inline struct sk_buff_head *band2list(struct pfifo_fast_priv *priv, - int band) +static inline struct skb_array *band2list(struct pfifo_fast_priv *priv, + int band) { - return priv->q + band; + return &priv->q[band]; } static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc, struct sk_buff **to_free) { - if (skb_queue_len(&qdisc->q) < qdisc_dev(qdisc)->tx_queue_len) { - int band = prio2band[skb->priority & TC_PRIO_MAX]; - struct pfifo_fast_priv *priv = qdisc_priv(qdisc); - struct sk_buff_head *list = band2list(priv, band); - - priv->bitmap |= (1 << band); - qdisc->q.qlen++; - return __qdisc_enqueue_tail(skb, qdisc, list); - } + int band = prio2band[skb->priority & TC_PRIO_MAX]; + struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + struct skb_array *q = band2list(priv, band); + int err; - return qdisc_drop(skb, qdisc, to_free); + err = skb_array_produce(q, skb); + + if (unlikely(err)) + return qdisc_drop_cpu(skb, qdisc, to_free); + + qdisc_qstats_cpu_qlen_inc(qdisc); + qdisc_qstats_cpu_backlog_inc(qdisc, skb); + return NET_XMIT_SUCCESS; } static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc) { struct pfifo_fast_priv *priv = qdisc_priv(qdisc); - int band = bitmap2band[priv->bitmap]; + struct sk_buff *skb = NULL; + int band; - if (likely(band >= 0)) { - struct sk_buff_head *list = band2list(priv, band); - struct sk_buff *skb = __qdisc_dequeue_head(qdisc, list); + for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) { + struct skb_array *q = band2list(priv, band); - qdisc->q.qlen--; - if (skb_queue_empty(list)) - priv->bitmap &= ~(1 << band); + if (__skb_array_empty(q)) + continue; - return skb; + skb = skb_array_consume(q); } - return NULL; -} - -static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc) -{ - struct pfifo_fast_priv *priv = qdisc_priv(qdisc); - int band = bitmap2band[priv->bitmap]; - - if (band >= 0) { - struct sk_buff_head *list = band2list(priv, band); - - return skb_peek(list); + if (likely(skb)) { + qdisc_qstats_cpu_backlog_dec(qdisc, skb); + qdisc_bstats_cpu_update(qdisc, skb); + qdisc_qstats_cpu_qlen_dec(qdisc); } - return NULL; + return skb; } static void pfifo_fast_reset(struct Qdisc *qdisc) { - int prio; + int i, band; struct pfifo_fast_priv *priv = qdisc_priv(qdisc); - for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) - __qdisc_reset_queue(band2list(priv, prio)); + for (band = 0; band < PFIFO_FAST_BANDS; band++) { + struct skb_array *q = band2list(priv, band); + struct sk_buff *skb; - priv->bitmap = 0; - qdisc->qstats.backlog = 0; - qdisc->q.qlen = 0; + while ((skb = skb_array_consume(q)) != NULL) + kfree_skb(skb); + } + + for_each_possible_cpu(i) { + struct gnet_stats_queue *q = per_cpu_ptr(qdisc->cpu_qstats, i); + + q->backlog = 0; + q->qlen = 0; + } } static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb) @@ -654,24 +646,53 @@ nla_put_failure: static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt) { - int prio; + unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len; struct pfifo_fast_priv *priv = qdisc_priv(qdisc); + int prio; + + /* guard against zero length rings */ + if (!qlen) + return -EINVAL; - for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) - __skb_queue_head_init(band2list(priv, prio)); + for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { + struct skb_array *q = band2list(priv, prio); + int err; + + err = skb_array_init(q, qlen, GFP_KERNEL); + if (err) + return -ENOMEM; + } + + atomic_set(&qdisc->qlen_atomic, 0); /* Can by-pass the queue discipline */ qdisc->flags |= TCQ_F_CAN_BYPASS; + qdisc->flags |= TCQ_F_NOLOCK; + qdisc->flags |= TCQ_F_CPUSTATS; + return 0; } +static void pfifo_fast_destroy(struct Qdisc *sch) +{ + struct pfifo_fast_priv *priv = qdisc_priv(sch); + int prio; + + for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) { + struct skb_array *q = band2list(priv, prio); + + skb_array_cleanup(q); + } +} + struct Qdisc_ops pfifo_fast_ops __read_mostly = { .id = "pfifo_fast", .priv_size = sizeof(struct pfifo_fast_priv), .enqueue = pfifo_fast_enqueue, .dequeue = pfifo_fast_dequeue, - .peek = pfifo_fast_peek, + .peek = qdisc_peek_dequeued_cpu, .init = pfifo_fast_init, + .destroy = pfifo_fast_destroy, .reset = pfifo_fast_reset, .dump = pfifo_fast_dump, .owner = THIS_MODULE,