From 1c0d32fde5bdf1184bc274f864c09799278a1114 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 4 Dec 2016 09:48:16 -0800 Subject: net_sched: gen_estimator: complete rewrite of rate estimators 1) Old code was hard to maintain, due to complex lock chains. (We probably will be able to remove some kfree_rcu() in callers) 2) Using a single timer to update all estimators does not scale. 3) Code was buggy on 32bit kernel (WRITE_ONCE() on 64bit quantity is not supposed to work well) In this rewrite : - I removed the RB tree that had to be scanned in gen_estimator_active(). qdisc dumps should be much faster. - Each estimator has its own timer. - Estimations are maintained in net_rate_estimator structure, instead of dirtying the qdisc. Minor, but part of the simplification. - Reading the estimator uses RCU and a seqcount to provide proper support for 32bit kernels. - We reduce memory need when estimators are not used, since we store a pointer, instead of the bytes/packets counters. - xt_rateest_mt() no longer has to grab a spinlock. (In the future, xt_rateest_tg() could be switched to per cpu counters) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_qfq.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'net/sched/sch_qfq.c') diff --git a/net/sched/sch_qfq.c b/net/sched/sch_qfq.c index ca0516e6f743..f9e712ce2d15 100644 --- a/net/sched/sch_qfq.c +++ b/net/sched/sch_qfq.c @@ -137,7 +137,7 @@ struct qfq_class { struct gnet_stats_basic_packed bstats; struct gnet_stats_queue qstats; - struct gnet_stats_rate_est64 rate_est; + struct net_rate_estimator __rcu *rate_est; struct Qdisc *qdisc; struct list_head alist; /* Link for active-classes list. */ struct qfq_aggregate *agg; /* Parent aggregate. */ @@ -508,7 +508,7 @@ set_change_agg: new_agg = kzalloc(sizeof(*new_agg), GFP_KERNEL); if (new_agg == NULL) { err = -ENOBUFS; - gen_kill_estimator(&cl->bstats, &cl->rate_est); + gen_kill_estimator(&cl->rate_est); goto destroy_class; } sch_tree_lock(sch); @@ -533,7 +533,7 @@ static void qfq_destroy_class(struct Qdisc *sch, struct qfq_class *cl) struct qfq_sched *q = qdisc_priv(sch); qfq_rm_from_agg(q, cl); - gen_kill_estimator(&cl->bstats, &cl->rate_est); + gen_kill_estimator(&cl->rate_est); qdisc_destroy(cl->qdisc); kfree(cl); } @@ -667,7 +667,7 @@ static int qfq_dump_class_stats(struct Qdisc *sch, unsigned long arg, if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), d, NULL, &cl->bstats) < 0 || - gnet_stats_copy_rate_est(d, &cl->bstats, &cl->rate_est) < 0 || + gnet_stats_copy_rate_est(d, &cl->rate_est) < 0 || gnet_stats_copy_queue(d, NULL, &cl->qdisc->qstats, cl->qdisc->q.qlen) < 0) return -1; -- cgit v1.2.3