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authorEric Dumazet <edumazet@google.com>2016-12-04 20:48:16 +0300
committerDavid S. Miller <davem@davemloft.net>2016-12-05 23:21:59 +0300
commit1c0d32fde5bdf1184bc274f864c09799278a1114 (patch)
tree47367d46dfc125e19294c3f5fa9a021520bd5660 /net/sched/sch_drr.c
parenta6e169312971219a34927e8fdece60046fafb8ba (diff)
downloadlinux-1c0d32fde5bdf1184bc274f864c09799278a1114.tar.xz
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 <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_drr.c')
-rw-r--r--net/sched/sch_drr.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c
index 8af5c59eef84..bb4cbdf75004 100644
--- a/net/sched/sch_drr.c
+++ b/net/sched/sch_drr.c
@@ -25,7 +25,7 @@ struct drr_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 list_head alist;
struct Qdisc *qdisc;
@@ -142,7 +142,7 @@ static int drr_change_class(struct Qdisc *sch, u32 classid, u32 parentid,
static void drr_destroy_class(struct Qdisc *sch, struct drr_class *cl)
{
- gen_kill_estimator(&cl->bstats, &cl->rate_est);
+ gen_kill_estimator(&cl->rate_est);
qdisc_destroy(cl->qdisc);
kfree(cl);
}
@@ -283,7 +283,7 @@ static int drr_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, qlen) < 0)
return -1;