Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4db0acf3 authored by Jarek Poplawski's avatar Jarek Poplawski Committed by David S. Miller
Browse files

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: default avatarBadalian Vyacheslav <slavon@bigtelecom.ru>
Reported-by: default avatarDenys Fedoryshchenko <denys@visp.net.lb>
Signed-off-by: default avatarJarek Poplawski <jarkao2@gmail.com>
Acked-by: default avatarJamal Hadi Salim <hadi@cyberus.ca>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3f0947c3

net/core/gen_estimator.c

+56 −20
Original line number Diff line number Diff line
@@ -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;

}
@@ -209,26 +255,17 @@ 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)

{

	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;
@@ -238,7 +275,6 @@ void gen_kill_estimator(struct gnet_stats_basic *bstats, 
		call_rcu(&e->e_rcu, __gen_kill_estimator);

	}

}

}



/**

 * gen_replace_estimator - replace rate estimator configuration