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/core/gen_stats.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) (limited to 'net/core/gen_stats.c') diff --git a/net/core/gen_stats.c b/net/core/gen_stats.c index 508e051304fb..87f28557b329 100644 --- a/net/core/gen_stats.c +++ b/net/core/gen_stats.c @@ -194,8 +194,7 @@ EXPORT_SYMBOL(gnet_stats_copy_basic); /** * gnet_stats_copy_rate_est - copy rate estimator statistics into statistics TLV * @d: dumping handle - * @b: basic statistics - * @r: rate estimator statistics + * @rate_est: rate estimator * * Appends the rate estimator statistics to the top level TLV created by * gnet_stats_start_copy(). @@ -205,18 +204,17 @@ EXPORT_SYMBOL(gnet_stats_copy_basic); */ int gnet_stats_copy_rate_est(struct gnet_dump *d, - const struct gnet_stats_basic_packed *b, - struct gnet_stats_rate_est64 *r) + struct net_rate_estimator __rcu **rate_est) { + struct gnet_stats_rate_est64 sample; struct gnet_stats_rate_est est; int res; - if (b && !gen_estimator_active(b, r)) + if (!gen_estimator_read(rate_est, &sample)) return 0; - - est.bps = min_t(u64, UINT_MAX, r->bps); + est.bps = min_t(u64, UINT_MAX, sample.bps); /* we have some time before reaching 2^32 packets per second */ - est.pps = r->pps; + est.pps = sample.pps; if (d->compat_tc_stats) { d->tc_stats.bps = est.bps; @@ -226,11 +224,11 @@ gnet_stats_copy_rate_est(struct gnet_dump *d, if (d->tail) { res = gnet_stats_copy(d, TCA_STATS_RATE_EST, &est, sizeof(est), TCA_STATS_PAD); - if (res < 0 || est.bps == r->bps) + if (res < 0 || est.bps == sample.bps) return res; /* emit 64bit stats only if needed */ - return gnet_stats_copy(d, TCA_STATS_RATE_EST64, r, sizeof(*r), - TCA_STATS_PAD); + return gnet_stats_copy(d, TCA_STATS_RATE_EST64, &sample, + sizeof(sample), TCA_STATS_PAD); } return 0; -- cgit v1.2.3-58-ga151