Messages in this thread | | | Date | Wed, 29 Oct 2014 22:03:20 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: e1000_netpoll(): disable_irq() triggers might_sleep() on linux-next |
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On Wed, 29 Oct 2014, Peter Zijlstra wrote:
> 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.
Well, if the net_device is not cache hot on irq entry you have lost already. The extra branch/lock is not going to add much to that.
Thanks,
tglx
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