netdev - Re: [RFC PATCH 1/5] net: implement support for low latency socket polling

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Message-ID: <20130304035527.GF3401@two.firstfloor.org>
Date:	Mon, 4 Mar 2013 04:55:27 +0100
From:	Andi Kleen <andi@...stfloor.org>
To:	Eric Dumazet <eric.dumazet@...il.com>
Cc:	Andi Kleen <andi@...stfloor.org>,
	Eliezer Tamir <eliezer.tamir@...ux.jf.intel.com>,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	Dave Miller <davem@...emloft.net>,
	Jesse Brandeburg <jesse.brandeburg@...el.com>,
	e1000-devel@...ts.sourceforge.net,
	Willem de Bruijn <willemb@...gle.com>, HPA <hpa@...or.com>,
	Eliezer Tamir <eliezer@...ir.org.il>
Subject: Re: [RFC PATCH 1/5] net: implement support for low latency socket
 polling

On Sun, Mar 03, 2013 at 01:20:01PM -0800, Eric Dumazet wrote:
> On Sun, 2013-03-03 at 20:21 +0100, Andi Kleen wrote:
> > > Alternative to 2) would be to use a generation id, incremented every
> > > time a napi used in spin polling enabled driver is dismantled (and freed
> > > after RCU grace period)
> > > 
> > > And store in sockets not only the pointer to napi_struct, but the
> > > current generation id : If the generation id doesnt match, disable
> > > the spinpoll until next packet rebuilds the cache again.
> > 
> > This would require rcu_read_lock, aka preempt off, during polling, right?
> > 
> 
> Of course, polling probably needs BH disabling as well to get the per
> napi lock

Ok maybe the cond_resched() is good enough.

-Andi

-- 
ak@...ux.intel.com -- Speaking for myself only.
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