netdev - Re: [PATCH ipvs-next] ipvs: Remove rcu_read_unlock();rcu_read

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Date:	Fri, 26 Apr 2013 02:59:26 +0200
From:	Pablo Neira Ayuso <pablo@...filter.org>
To:	Julian Anastasov <ja@....bg>
Cc:	Simon Horman <horms@...ge.net.au>, lvs-devel@...r.kernel.org,
	netdev@...r.kernel.org, netfilter-devel@...r.kernel.org,
	Wensong Zhang <wensong@...ux-vs.org>
Subject: Re: [PATCH ipvs-next] ipvs: Remove rcu_read_unlock();rcu_read_lock();

Hi Julian,

On Thu, Apr 25, 2013 at 11:15:25AM +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.

We seem to be supporting over that limit via module_param and sysfs:

/sys/module/nf_conntrack/parameters/hashsize

Regards.
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