From: "Maciej W. Rozycki" <macro@orcam.me.uk>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: netdev@vger.kernel.org, linux-mips@vger.kernel.org,
Jakub Kicinski <kuba@kernel.org>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>
Subject: Re: [PATCH net-next v2] declance: Remove IRQF_ONESHOT
Date: Mon, 4 May 2026 23:35:42 +0100 (BST) [thread overview]
Message-ID: <alpine.DEB.2.21.2605042332070.46195@angie.orcam.me.uk> (raw)
In-Reply-To: <alpine.DEB.2.21.2603292037020.60268@angie.orcam.me.uk>
On Sun, 29 Mar 2026, Maciej W. Rozycki wrote:
> I've now got back to it and while preparing the justification for the
> removal of the IRQF_ONESHOT recommendation and having looked through
> Documentation/core-api/real-time/differences.rst I became stumped and
> need a further clarification after all.
>
> I read in the document that:
>
> "However, on a PREEMPT_RT system, interrupts are forced-threaded and no
> longer run in hard IRQ context."
>
> and:
>
> "All interrupts are forced-threaded in a PREEMPT_RT system. The exceptions
> are interrupts that are requested with the IRQF_NO_THREAD, IRQF_PERCPU, or
> IRQF_ONESHOT flags."
>
> -- do I infer correctly that on a PREEMPT_RT system in the absence of any
> flags passed to request_irq() the handler requested such as one concerned
> here (i.e. lance_dma_merr_int()) will run with interrupts locally enabled
> on the CPU?
No reply, but I've gone through irq_setup_forced_threading() now and my
inference was indeed correct, and the handler does need to be installed
with IRQF_NO_THREAD. I'll send corrective patches shortly.
Maciej
next prev parent reply other threads:[~2026-05-04 22:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-01-27 13:53 [PATCH net-next v2] declance: Remove IRQF_ONESHOT Sebastian Andrzej Siewior
2026-01-27 15:46 ` Maciej W. Rozycki
2026-01-27 16:54 ` Sebastian Andrzej Siewior
2026-01-27 18:35 ` Maciej W. Rozycki
2026-03-29 20:27 ` Maciej W. Rozycki
2026-05-04 22:35 ` Maciej W. Rozycki [this message]
2026-05-05 7:29 ` Sebastian Andrzej Siewior
2026-05-05 12:02 ` Maciej W. Rozycki
2026-05-05 12:32 ` Sebastian Andrzej Siewior
2026-05-05 14:00 ` Maciej W. Rozycki
2026-05-05 15:24 ` Sebastian Andrzej Siewior
2026-05-06 9:25 ` Maciej W. Rozycki
2026-05-07 7:34 ` Sebastian Andrzej Siewior
2026-05-07 11:45 ` Maciej W. Rozycki
2026-01-29 3:50 ` patchwork-bot+netdevbpf
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