From 4db0acf3c0afbbbb2ae35a65f8896ca6655a47ec Mon Sep 17 00:00:00 2001 From: Jarek Poplawski Date: Mon, 24 Nov 2008 15:48:05 -0800 Subject: [PATCH] net: gen_estimator: Fix gen_kill_estimator() lookups gen_kill_estimator() linear lists lookups are very slow, and e.g. while deleting a large number of HTB classes soft lockups were reported. Here is another try to fix this problem: this time internally, with rbtree, so similarly to Jamal's hashing idea IIRC. (Looking for next hits could be still optimized, but it's really fast as it is.) Reported-by: Badalian Vyacheslav Reported-by: Denys Fedoryshchenko Signed-off-by: Jarek Poplawski Acked-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- net/core/gen_estimator.c | 76 +++++++++++++++++++++++++++++----------- 1 file changed, 56 insertions(+), 20 deletions(-) diff --git a/net/core/gen_estimator.c b/net/core/gen_estimator.c index 57abe8266be1..80aa160877e9 100644 --- a/net/core/gen_estimator.c +++ b/net/core/gen_estimator.c @@ -31,6 +31,7 @@ #include #include #include +#include #include #include @@ -89,6 +90,7 @@ struct gen_estimator u32 avpps; u32 avbps; struct rcu_head e_rcu; + struct rb_node node; }; struct gen_estimator_head @@ -102,6 +104,9 @@ static struct gen_estimator_head elist[EST_MAX_INTERVAL+1]; /* Protects against NULL dereference */ static DEFINE_RWLOCK(est_lock); +/* Protects against soft lockup during large deletion */ +static struct rb_root est_root = RB_ROOT; + static void est_timer(unsigned long arg) { int idx = (int)arg; @@ -139,6 +144,45 @@ static void est_timer(unsigned long arg) rcu_read_unlock(); } +static void gen_add_node(struct gen_estimator *est) +{ + struct rb_node **p = &est_root.rb_node, *parent = NULL; + + while (*p) { + struct gen_estimator *e; + + parent = *p; + e = rb_entry(parent, struct gen_estimator, node); + + if (est->bstats > e->bstats) + p = &parent->rb_right; + else + p = &parent->rb_left; + } + rb_link_node(&est->node, parent, p); + rb_insert_color(&est->node, &est_root); +} + +static struct gen_estimator *gen_find_node(struct gnet_stats_basic *bstats, + struct gnet_stats_rate_est *rate_est) +{ + struct rb_node *p = est_root.rb_node; + + while (p) { + struct gen_estimator *e; + + e = rb_entry(p, struct gen_estimator, node); + + if (bstats > e->bstats) + p = p->rb_right; + else if (bstats < e->bstats || rate_est != e->rate_est) + p = p->rb_left; + else + return e; + } + return NULL; +} + /** * gen_new_estimator - create a new rate estimator * @bstats: basic statistics @@ -194,6 +238,8 @@ int gen_new_estimator(struct gnet_stats_basic *bstats, mod_timer(&elist[idx].timer, jiffies + ((HZ/4) << idx)); list_add_rcu(&est->list, &elist[idx].list); + gen_add_node(est); + return 0; } @@ -209,34 +255,24 @@ static void __gen_kill_estimator(struct rcu_head *head) * @bstats: basic statistics * @rate_est: rate estimator statistics * - * Removes the rate estimator specified by &bstats and &rate_est - * and deletes the timer. + * Removes the rate estimator specified by &bstats and &rate_est. * * NOTE: Called under rtnl_mutex */ void gen_kill_estimator(struct gnet_stats_basic *bstats, - struct gnet_stats_rate_est *rate_est) + struct gnet_stats_rate_est *rate_est) { - int idx; - struct gen_estimator *e, *n; - - for (idx=0; idx <= EST_MAX_INTERVAL; idx++) { - - /* Skip non initialized indexes */ - if (!elist[idx].timer.function) - continue; + struct gen_estimator *e; - list_for_each_entry_safe(e, n, &elist[idx].list, list) { - if (e->rate_est != rate_est || e->bstats != bstats) - continue; + while ((e = gen_find_node(bstats, rate_est))) { + rb_erase(&e->node, &est_root); - write_lock_bh(&est_lock); - e->bstats = NULL; - write_unlock_bh(&est_lock); + write_lock_bh(&est_lock); + e->bstats = NULL; + write_unlock_bh(&est_lock); - list_del_rcu(&e->list); - call_rcu(&e->e_rcu, __gen_kill_estimator); - } + list_del_rcu(&e->list); + call_rcu(&e->e_rcu, __gen_kill_estimator); } } -- GitLab