From: Heiner Kallweit <hkallweit1@gmail.com>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>, netdev <netdev@vger.kernel.org>,
Realtek linux nic maintainers <nic_swsd@realtek.com>
Subject: Re: [patchlet] r8169: fix napi_schedule_irqoff() called with irqs enabled warning
Date: Fri, 16 Oct 2020 16:41:50 +0200 [thread overview]
Message-ID: <a3c87f21-7e49-99a5-026f-4a24e0cb7a86@gmail.com> (raw)
In-Reply-To: <20201016142611.zpp63qppmazxl4k7@skbuf>
On 16.10.2020 16:26, Vladimir Oltean wrote:
> On Fri, Oct 16, 2020 at 01:34:55PM +0200, Heiner Kallweit wrote:
>> I'm aware of the topic, but missing the benefits of the irqoff version
>> unconditionally doesn't seem to be the best option.
>
> What are the benefits of the irqoff version? As far as I see it, the
> only use case for that function is when the caller has _explicitly_
> disabled interrupts.
>
If the irqoff version wouldn't have a benefit, then I think we wouldn't
have it ..
> The plain napi_schedule call will check if irqs are disabled. If they
> are, it won't do anything further in that area. There is no performance
> impact except for a check.
>
There is no such check, and in general currently attempts are made to
remove usage of e.g. in_interrupt(). napi_schedule() has additional calls
to local_irq_save() and local_irq_restore().
>> Needed is a function that dynamically picks the right version.
>
> So you want to replace a check with another check, am I right? How will
> that improve anything performance-wise?
>
next prev parent reply other threads:[~2020-10-16 14:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 11:26 [patchlet] r8169: fix napi_schedule_irqoff() called with irqs enabled warning Mike Galbraith
2020-10-16 11:34 ` Heiner Kallweit
2020-10-16 11:57 ` Mike Galbraith
2020-10-16 14:26 ` Vladimir Oltean
2020-10-16 14:41 ` Heiner Kallweit [this message]
2020-10-16 15:40 ` Vladimir Oltean
2020-10-16 17:11 ` Mike Galbraith
2020-10-16 17:19 ` Vladimir Oltean
2020-10-16 19:15 ` Heiner Kallweit
2020-10-17 2:26 ` Mike Galbraith
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