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From: wen.yang@linux.dev
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable@vger.kernel.org, linux-kernel@vger.kernel.org,
	Wen Yang <wen.yang@linux.dev>
Subject: [PATCH 6.6 0/2] fix do_softirq_post_smp_call_flush warnings caused by NET_RX_SOFTIRQ
Date: Mon, 29 Dec 2025 15:53:15 +0800	[thread overview]
Message-ID: <cover.1766987153.git.wen.yang@linux.dev> (raw)

From: Wen Yang <wen.yang@linux.dev>

do_softirq_post_smp_call_flush() on PREEMPT_RT kernels carries a
WARN_ON_ONCE() for any SOFTIRQ being raised from an SMP-call-function.
Since do_softirq_post_smp_call_flush() is called with preempt disabled,
raising a SOFTIRQ during flush_smp_call_function_queue() can lead to
longer preempt disabled sections.

RPS distributes network processing load across CPUs by enqueuing
packets on a remote CPU's backlog and raising NET_RX_SOFTIRQ to
process them.
    
The following patches fixes this issue.

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, 115 insertions(+), 47 deletions(-)

-- 
2.25.1


             reply	other threads:[~2025-12-29  7:53 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-12-29  7:53 wen.yang [this message]
2025-12-29  7:53 ` [PATCH 6.6 1/2] net: Remove conditional threaded-NAPI wakeup based on task state wen.yang
2025-12-29  7:53 ` [PATCH 6.6 2/2] net: Allow to use SMP threads for backlog NAPI wen.yang

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