linux-kernel - Re: [PATCH 6.6 0/3] net: Backlog NAPI threading for PREEMPT

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Message-ID: <2f5f4a18-82b4-4f67-ae98-cdf5b7f8012b@linux.dev>
Date: Mon, 19 Jan 2026 01:02:47 +0800
From: Wen Yang <wen.yang@...ux.dev>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: stable@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6.6 0/3] net: Backlog NAPI threading for PREEMPT_RT



Sorry, we accidentally wrote 'PATCH 6.1' as' PATCH 6.6 ', please ignore 
this series.
We will resend the correct one, thanks.

--
Best wishes,
Wen


On 1/19/26 00:15, wen.yang@...ux.dev wrote:
> From: Wen Yang <wen.yang@...ux.dev>
> 
> Backport three upstream commits to fix a warning on PREEMPT_RT kernels
> where raising SOFTIRQ from smp_call_functio triggers WARN_ON_ONCE()
> in do_softirq_post_smp_call_flush().
> 
> The issue occurs when RPS sends IPIs for backlog NAPI, causing softirqs
> from irq context on PREEMPT_RT. The solution implements backlog
> NAPI threads to avoid IPI-triggered softirqs, which is required for
> PREEMPT_RT kernels.
> 
> commit 8fcb76b934da ("net: napi_schedule_rps() cleanup") and
> commit 56364c910691 ("net: Remove conditional threaded-NAPI wakeup based on task state.")
> are prerequisites.
> 
> The remaining dependencies have not been backported, as they modify
> structure definitions in header files and represent optimizations
> rather than bug fixes, including:
> c59647c0dc67 net: add softnet_data.in_net_rx_action
> a1aaee7f8f79 net: make napi_threaded_poll() aware of sd->defer_list
> 87eff2ec57b6 net: optimize napi_threaded_poll() vs RPS/RFS
> 2b0cfa6e4956 net: add generic percpu page_pool allocator
> ...
> 
> Eric Dumazet (1):
>    net: napi_schedule_rps() cleanup
> 
> Sebastian Andrzej Siewior (2):
>    net: Remove conditional threaded-NAPI wakeup based on task state.
>    net: Allow to use SMP threads for backlog NAPI.
> 
>   net/core/dev.c | 162 +++++++++++++++++++++++++++++++++++--------------
>   1 file changed, 118 insertions(+), 44 deletions(-)
>