Hello On Thu, 2013-04-25 at 11:15 +0300, Julian Anastasov wrote: > Hello, > > On Thu, 25 Apr 2013, Simon Horman wrote: > > > It is unclear to me that there is any utility in the following: > > > > rcu_read_unlock(); > > rcu_read_lock(); > > I thought it is a good idea for fixed hash table > of IP_VS_TAB_BITS=20. May be if guarded by > > if (!((++idx) & 4095)) > > to reduce its rate to 256 (with idx++ removed from the for loop) ? > > Netfilter has no such logic for nf_conntrack because > it has limit of 16384 rows. Not sure how fatal is to try 1048576 > empty rows under RCU lock for such rare operations as > connection listing. OTOH, ip_vs_conn_array() needs to > seek at some initial position, so it can skip many > entries if reading table with many conns, for example, > 1048576 rows * 16 conns per row, we will need to > touch 16777216 conns under lock. Not sure what is the > best practice for such cases. My opinion is to keep it, people tends to do such "rare" things. It's not unusual with 256k - 1M rows... Regards Hans
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