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ipvs: use cond_resched_rcu() helper when walking connections 

This avoids the situation where walking of a large number of connections
may prevent scheduling for a long time while also avoiding excessive
calls to rcu_read_unlock() and rcu_read_lock().

Note that in the case of !CONFIG_PREEMPT_RCU this will
add a call to cond_resched().

Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Simon Horman 2013-05-22 14:50:32 +09:00 committed by Pablo Neira Ayuso
parent f6f3c437d0
commit a38e5e230e
1 changed files with 8 additions and 15 deletions
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23
net/netfilter/ipvs/ip_vs_conn.c
View File

@ -975,8 +975,7 @@ static void *ip_vs_conn_array(struct seq_file *seq, loff_t pos)
return cp;
}
}
rcu_read_unlock();
rcu_read_lock();
cond_resched_rcu();
}
return NULL;
@ -1015,8 +1014,7 @@ static void *ip_vs_conn_seq_next(struct seq_file *seq, void *v, loff_t *pos)
iter->l = &ip_vs_conn_tab[idx];
return cp;
}
rcu_read_unlock();
rcu_read_lock();
cond_resched_rcu();
}
iter->l = NULL;
return NULL;
@ -1206,17 +1204,13 @@ void ip_vs_random_dropentry(struct net *net)
int idx;
struct ip_vs_conn *cp, *cp_c;
rcu_read_lock();
/*
* Randomly scan 1/32 of the whole table every second
*/
for (idx = 0; idx < (ip_vs_conn_tab_size>>5); idx++) {
unsigned int hash = net_random() & ip_vs_conn_tab_mask;
/*
* Lock is actually needed in this loop.
*/
rcu_read_lock();
hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[hash], c_list) {
if (cp->flags & IP_VS_CONN_F_TEMPLATE)
/* connection template */
@ -1252,8 +1246,9 @@ void ip_vs_random_dropentry(struct net *net)
__ip_vs_conn_put(cp);
}
}
rcu_read_unlock();
cond_resched_rcu();
}
rcu_read_unlock();
}
@ -1267,11 +1262,8 @@ static void ip_vs_conn_flush(struct net *net)
struct netns_ipvs *ipvs = net_ipvs(net);
flush_again:
rcu_read_lock();
for (idx = 0; idx < ip_vs_conn_tab_size; idx++) {
/*
* Lock is actually needed in this loop.
*/
rcu_read_lock();
hlist_for_each_entry_rcu(cp, &ip_vs_conn_tab[idx], c_list) {
if (!ip_vs_conn_net_eq(cp, net))
@ -1286,8 +1278,9 @@ flush_again:
__ip_vs_conn_put(cp);
}
}
rcu_read_unlock();
cond_resched_rcu();
}
rcu_read_unlock();
/* the counter may be not NULL, because maybe some conn entries
are run by slow timer handler or unhashed but still referred */