linux-kernel - Re: [PATCH 6.6 3/3] net: Allow to use SMP threads for backlog NAPI.

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Message-ID: <20260120103833.4kssDD1Y@linutronix.de>
Date: Tue, 20 Jan 2026 11:38:33 +0100
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: Jakub Kicinski <kuba@...nel.org>, wen.yang@...ux.dev,
	stable@...r.kernel.org, linux-kernel@...r.kernel.org,
	Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCH 6.6 3/3] net: Allow to use SMP threads for backlog NAPI.

On 2026-01-20 10:21:58 [+0100], Greg Kroah-Hartman wrote:
> > > Please see patch 0/3 in this series:
> > > 	https://lore.kernel.org/all/cover.1768751557.git.wen.yang@linux.dev/
> > 
> > The reasoning why this is needed is due to PREEMPT_RT. This targets v6.6
> > and PREEMPT_RT is officially supported upstream since v6.12. For v6.6
> > you still need the out-of-tree patch. This means not only select the
> > Kconfig symbol but also a bit futex, ptrace or printk. This queue does
> > not include the three patches here but has another workaround having
> > more or less the same effect.
> > 
> > If this is needed only for PREEMPT_RT's sake I would suggest to route it
> > via the stable-rt instead and replace what is currently there.
> 
> It's already merged, should this be reverted?  I forgot RT was only for
> 6.12 and newer, sorry.

Jakub doesn't seem to be thrilled about this backport and I don't see a
requirement for it. Based on this yes, please revert it.

If Wen wants this still to happen he should either provide better
reasoning why this is needed based on the latest stable v6.6 as-is or
ask stable-rt team to take this instead the current workaround.

> greg k-h

Sebastian