From 89819dc01f4c5920783f561597a48d9d75220e9e Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Sun, 15 Dec 2013 20:15:09 -0800 Subject: [PATCH] net_sched: convert tcf_hashinfo to hlist and use spinlock So that we don't need to play with singly linked list, and since the code is not on hot path, we can use spinlock instead of rwlock. Cc: Jamal Hadi Salim Cc: David S. Miller Signed-off-by: Cong Wang Signed-off-by: Jamal Hadi Salim Signed-off-by: David S. Miller --- include/net/act_api.h | 16 ++++++---- net/sched/act_api.c | 69 ++++++++++++++++++------------------------ net/sched/act_police.c | 45 +++++++++++---------------- 3 files changed, 58 insertions(+), 72 deletions(-) diff --git a/include/net/act_api.h b/include/net/act_api.h index 2b5ec5abfeb3..22418d1a8396 100644 --- a/include/net/act_api.h +++ b/include/net/act_api.h @@ -9,7 +9,7 @@ #include struct tcf_common { - struct tcf_common *tcfc_next; + struct hlist_node tcfc_head; u32 tcfc_index; int tcfc_refcnt; int tcfc_bindcnt; @@ -22,7 +22,7 @@ struct tcf_common { spinlock_t tcfc_lock; struct rcu_head tcfc_rcu; }; -#define tcf_next common.tcfc_next +#define tcf_head common.tcfc_head #define tcf_index common.tcfc_index #define tcf_refcnt common.tcfc_refcnt #define tcf_bindcnt common.tcfc_bindcnt @@ -36,9 +36,9 @@ struct tcf_common { #define tcf_rcu common.tcfc_rcu struct tcf_hashinfo { - struct tcf_common **htab; + struct hlist_head *htab; unsigned int hmask; - rwlock_t lock; + spinlock_t lock; }; static inline unsigned int tcf_hash(u32 index, unsigned int hmask) @@ -48,12 +48,16 @@ static inline unsigned int tcf_hash(u32 index, unsigned int hmask) static inline int tcf_hashinfo_init(struct tcf_hashinfo *hf, unsigned int mask) { - rwlock_init(&hf->lock); + int i; + + spin_lock_init(&hf->lock); hf->hmask = mask; - hf->htab = kzalloc((mask + 1) * sizeof(struct tcf_common *), + hf->htab = kzalloc((mask + 1) * sizeof(struct hlist_head), GFP_KERNEL); if (!hf->htab) return -ENOMEM; + for (i = 0; i < mask + 1; i++) + INIT_HLIST_HEAD(&hf->htab[i]); return 0; } diff --git a/net/sched/act_api.c b/net/sched/act_api.c index 125673d5d877..dc457c957656 100644 --- a/net/sched/act_api.c +++ b/net/sched/act_api.c @@ -29,25 +29,16 @@ void tcf_hash_destroy(struct tcf_common *p, struct tcf_hashinfo *hinfo) { - unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask); - struct tcf_common **p1p; - - for (p1p = &hinfo->htab[h]; *p1p; p1p = &(*p1p)->tcfc_next) { - if (*p1p == p) { - write_lock_bh(&hinfo->lock); - *p1p = p->tcfc_next; - write_unlock_bh(&hinfo->lock); - gen_kill_estimator(&p->tcfc_bstats, - &p->tcfc_rate_est); - /* - * gen_estimator est_timer() might access p->tcfc_lock - * or bstats, wait a RCU grace period before freeing p - */ - kfree_rcu(p, tcfc_rcu); - return; - } - } - WARN_ON(1); + spin_lock_bh(&hinfo->lock); + hlist_del(&p->tcfc_head); + spin_unlock_bh(&hinfo->lock); + gen_kill_estimator(&p->tcfc_bstats, + &p->tcfc_rate_est); + /* + * gen_estimator est_timer() might access p->tcfc_lock + * or bstats, wait a RCU grace period before freeing p + */ + kfree_rcu(p, tcfc_rcu); } EXPORT_SYMBOL(tcf_hash_destroy); @@ -73,18 +64,19 @@ EXPORT_SYMBOL(tcf_hash_release); static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb, struct tc_action *a, struct tcf_hashinfo *hinfo) { + struct hlist_head *head; struct tcf_common *p; int err = 0, index = -1, i = 0, s_i = 0, n_i = 0; struct nlattr *nest; - read_lock_bh(&hinfo->lock); + spin_lock_bh(&hinfo->lock); s_i = cb->args[0]; for (i = 0; i < (hinfo->hmask + 1); i++) { - p = hinfo->htab[tcf_hash(i, hinfo->hmask)]; + head = &hinfo->htab[tcf_hash(i, hinfo->hmask)]; - for (; p; p = p->tcfc_next) { + hlist_for_each_entry_rcu(p, head, tcfc_head) { index++; if (index < s_i) continue; @@ -107,7 +99,7 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb, } } done: - read_unlock_bh(&hinfo->lock); + spin_unlock_bh(&hinfo->lock); if (n_i) cb->args[0] += n_i; return n_i; @@ -120,7 +112,9 @@ static int tcf_dump_walker(struct sk_buff *skb, struct netlink_callback *cb, static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a, struct tcf_hashinfo *hinfo) { - struct tcf_common *p, *s_p; + struct hlist_head *head; + struct hlist_node *n; + struct tcf_common *p; struct nlattr *nest; int i = 0, n_i = 0; @@ -130,14 +124,11 @@ static int tcf_del_walker(struct sk_buff *skb, struct tc_action *a, if (nla_put_string(skb, TCA_KIND, a->ops->kind)) goto nla_put_failure; for (i = 0; i < (hinfo->hmask + 1); i++) { - p = hinfo->htab[tcf_hash(i, hinfo->hmask)]; - - while (p != NULL) { - s_p = p->tcfc_next; + head = &hinfo->htab[tcf_hash(i, hinfo->hmask)]; + hlist_for_each_entry_safe(p, n, head, tcfc_head) { if (ACT_P_DELETED == tcf_hash_release(p, 0, hinfo)) module_put(a->ops->owner); n_i++; - p = s_p; } } if (nla_put_u32(skb, TCA_FCNT, n_i)) @@ -168,15 +159,15 @@ EXPORT_SYMBOL(tcf_generic_walker); struct tcf_common *tcf_hash_lookup(u32 index, struct tcf_hashinfo *hinfo) { - struct tcf_common *p; + struct tcf_common *p = NULL; + struct hlist_head *head; - read_lock_bh(&hinfo->lock); - for (p = hinfo->htab[tcf_hash(index, hinfo->hmask)]; p; - p = p->tcfc_next) { + spin_lock_bh(&hinfo->lock); + head = &hinfo->htab[tcf_hash(index, hinfo->hmask)]; + hlist_for_each_entry_rcu(p, head, tcfc_head) if (p->tcfc_index == index) break; - } - read_unlock_bh(&hinfo->lock); + spin_unlock_bh(&hinfo->lock); return p; } @@ -236,6 +227,7 @@ struct tcf_common *tcf_hash_create(u32 index, struct nlattr *est, p->tcfc_bindcnt = 1; spin_lock_init(&p->tcfc_lock); + INIT_HLIST_NODE(&p->tcfc_head); p->tcfc_index = index ? index : tcf_hash_new_index(idx_gen, hinfo); p->tcfc_tm.install = jiffies; p->tcfc_tm.lastuse = jiffies; @@ -257,10 +249,9 @@ void tcf_hash_insert(struct tcf_common *p, struct tcf_hashinfo *hinfo) { unsigned int h = tcf_hash(p->tcfc_index, hinfo->hmask); - write_lock_bh(&hinfo->lock); - p->tcfc_next = hinfo->htab[h]; - hinfo->htab[h] = p; - write_unlock_bh(&hinfo->lock); + spin_lock_bh(&hinfo->lock); + hlist_add_head(&p->tcfc_head, &hinfo->htab[h]); + spin_unlock_bh(&hinfo->lock); } EXPORT_SYMBOL(tcf_hash_insert); diff --git a/net/sched/act_police.c b/net/sched/act_police.c index f201576d25c2..0cc305e7e469 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -60,18 +60,19 @@ struct tc_police_compat { static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *cb, int type, struct tc_action *a) { + struct hlist_head *head; struct tcf_common *p; int err = 0, index = -1, i = 0, s_i = 0, n_i = 0; struct nlattr *nest; - read_lock_bh(&police_hash_info.lock); + spin_lock_bh(&police_hash_info.lock); s_i = cb->args[0]; for (i = 0; i < (POL_TAB_MASK + 1); i++) { - p = police_hash_info.htab[tcf_hash(i, POL_TAB_MASK)]; + head = &police_hash_info.htab[tcf_hash(i, POL_TAB_MASK)]; - for (; p; p = p->tcfc_next) { + hlist_for_each_entry_rcu(p, head, tcfc_head) { index++; if (index < s_i) continue; @@ -94,7 +95,7 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c } } done: - read_unlock_bh(&police_hash_info.lock); + spin_unlock_bh(&police_hash_info.lock); if (n_i) cb->args[0] += n_i; return n_i; @@ -106,25 +107,16 @@ static int tcf_act_police_walker(struct sk_buff *skb, struct netlink_callback *c static void tcf_police_destroy(struct tcf_police *p) { - unsigned int h = tcf_hash(p->tcf_index, POL_TAB_MASK); - struct tcf_common **p1p; - - for (p1p = &police_hash_info.htab[h]; *p1p; p1p = &(*p1p)->tcfc_next) { - if (*p1p == &p->common) { - write_lock_bh(&police_hash_info.lock); - *p1p = p->tcf_next; - write_unlock_bh(&police_hash_info.lock); - gen_kill_estimator(&p->tcf_bstats, - &p->tcf_rate_est); - /* - * gen_estimator est_timer() might access p->tcf_lock - * or bstats, wait a RCU grace period before freeing p - */ - kfree_rcu(p, tcf_rcu); - return; - } - } - WARN_ON(1); + spin_lock_bh(&police_hash_info.lock); + hlist_del(&p->tcf_head); + spin_unlock_bh(&police_hash_info.lock); + gen_kill_estimator(&p->tcf_bstats, + &p->tcf_rate_est); + /* + * gen_estimator est_timer() might access p->tcf_lock + * or bstats, wait a RCU grace period before freeing p + */ + kfree_rcu(p, tcf_rcu); } static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = { @@ -259,10 +251,9 @@ static int tcf_act_police_locate(struct net *net, struct nlattr *nla, police->tcf_index = parm->index ? parm->index : tcf_hash_new_index(&police_idx_gen, &police_hash_info); h = tcf_hash(police->tcf_index, POL_TAB_MASK); - write_lock_bh(&police_hash_info.lock); - police->tcf_next = police_hash_info.htab[h]; - police_hash_info.htab[h] = &police->common; - write_unlock_bh(&police_hash_info.lock); + spin_lock_bh(&police_hash_info.lock); + hlist_add_head(&police->tcf_head, &police_hash_info.htab[h]); + spin_unlock_bh(&police_hash_info.lock); a->priv = police; return ret;