From: Jakub Kicinski <kuba@kernel.org>
To: Heiner Kallweit <hkallweit1@gmail.com>
Cc: John Keeping <john@metanate.com>,
netdev@vger.kernel.org,
Giuseppe Cavallaro <peppe.cavallaro@st.com>,
Alexandre Torgue <alexandre.torgue@st.com>,
Jose Abreu <joabreu@synopsys.com>,
"David S. Miller" <davem@davemloft.net>,
Maxime Coquelin <mcoquelin.stm32@gmail.com>,
linux-stm32@st-md-mailman.stormreply.com,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH] net: stmmac: Don't call _irqoff() with hardirqs enabled
Date: Sun, 11 Oct 2020 09:06:20 -0700 [thread overview]
Message-ID: <20201011090620.48afafd7@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <c73866a9-2ee8-b549-f578-75d62b9263b4@gmail.com>
On Sun, 11 Oct 2020 11:24:41 +0200 Heiner Kallweit wrote:
> >> qeth_qdio_poll
> >> netvsc_channel_cb
> >> napi_watchdog
> >
> > This one runs from a hrtimer, which I believe will be a hard irq
> > context on anything but RT. I could be wrong.
> >
>
> A similar discussion can be found e.g. here:
> https://lore.kernel.org/netdev/20191126222013.1904785-1-bigeasy@linutronix.de/
> However I don't see any actual outcome.
Interesting, hopefully Eric will chime in. I think the hrtimer issue
was solved. But I'm not actually seeing a lockdep_assert_irqs_disabled()
in __raise_softirq_irqoff() in net, so IDK what that's for?
In any case if NAPI thinks it has irqs off while they're not, and
interacts with other parts of the kernel we may be in for a game of
whack-a-mole.
Perhaps a way around touching force_irqthreads directly in net/ would
be some form of a helper like "theaded_local_irq_save" or such that'd
disable IRQs only if force_irqthreads == 1? Is that cheating? :)
next prev parent reply other threads:[~2020-10-11 16:07 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 16:27 [PATCH] net: stmmac: Don't call _irqoff() with hardirqs enabled John Keeping
2020-10-08 23:46 ` Vladimir Oltean
2020-10-09 9:59 ` John Keeping
2020-10-09 10:12 ` Vladimir Oltean
2020-10-09 14:54 ` Heiner Kallweit
2020-10-09 15:58 ` Jakub Kicinski
2020-10-09 16:06 ` Heiner Kallweit
2020-10-10 13:08 ` Heiner Kallweit
2020-10-10 15:22 ` Jakub Kicinski
2020-10-11 9:24 ` Heiner Kallweit
2020-10-11 16:06 ` Jakub Kicinski [this message]
2020-10-11 13:42 ` Heiner Kallweit
2020-10-11 15:56 ` Jakub Kicinski
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