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authorJarek Poplawski <jarkao2@gmail.com>2008-11-24 15:48:05 -0800
committerDavid S. Miller <davem@davemloft.net>2008-11-24 15:48:05 -0800
commit4db0acf3c0afbbbb2ae35a65f8896ca6655a47ec (patch)
treee13b52665a811f9c5ad3621a2408be1b4f70c78c
parent3f0947c3ffaed33c1c38b79e4b17f75ba072d3e9 (diff)
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 <slavon@bigtelecom.ru> Reported-by: Denys Fedoryshchenko <denys@visp.net.lb> Signed-off-by: Jarek Poplawski <jarkao2@gmail.com> Acked-by: Jamal Hadi Salim <hadi@cyberus.ca> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/core/gen_estimator.c76
1 files 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 <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/init.h>
+#include <linux/rbtree.h>
#include <net/sock.h>
#include <net/gen_stats.h>
@@ -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 @@ skip:
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);
}
}