From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Sabrina Dubroca <sd@queasysnail.net>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
jeffrey.t.kirsher@intel.com
Subject: Re: e1000_netpoll(): disable_irq() triggers might_sleep() on linux-next
Date: Wed, 29 Oct 2014 21:51:31 +0100 [thread overview]
Message-ID: <20141029205131.GI10501@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.11.1410292119350.5308@nanos>
On Wed, Oct 29, 2014 at 09:23:42PM +0100, Thomas Gleixner wrote:
> But at least it allows to mitigate the impact by making it conditional
> at a central point.
>
> static inline void netpoll_lock(struct net_device *nd)
> {
> if (netpoll_active(nd))
> spin_lock(&nd->netpoll_lock);
> }
branch fail vs lock might be a toss on most machines, but if we're
hitting cold cachelines we loose big.
> and let the core code make sure that activation/deactivation of
> netpoll on a particular interface is serialized against the interrupt
> and netpoll calls.
>
> Not sure if it's worth the trouble, but at least it allows to deal
> with it in the core instead of dealing with it on a per driver base.
Does multi-queue have one netdev per queue or does that need moar
logicz?
next prev parent reply other threads:[~2014-10-29 20:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-29 15:56 e1000_netpoll(): disable_irq() triggers might_sleep() on linux-next Sabrina Dubroca
2014-10-29 18:07 ` Peter Zijlstra
2014-10-29 18:33 ` Thomas Gleixner
2014-10-29 19:36 ` Peter Zijlstra
2014-10-29 19:40 ` Jeff Kirsher
2014-10-29 19:53 ` Thomas Gleixner
2014-10-29 19:49 ` Thomas Gleixner
2014-10-29 19:50 ` Peter Zijlstra
2014-10-29 20:07 ` Thomas Gleixner
2014-10-29 20:23 ` Thomas Gleixner
2014-10-29 20:51 ` Peter Zijlstra [this message]
2014-10-29 21:03 ` Thomas Gleixner
2014-12-02 16:35 ` Sabrina Dubroca
2014-12-22 15:28 ` Bart Van Assche
2015-01-05 10:06 ` Bart Van Assche
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