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Date: Fri, 7 Aug 2026 18:07:09 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Nam Cao <namcao@linutronix.de>
Cc: Kuniyuki Iwashima <kuniyu@google.com>, "David S . Miller"
 <davem@davemloft.net>, Eric Dumazet <edumazet@google.com>, Paolo Abeni
 <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
 netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-rt-devel@lists.linux.dev
Subject: Re: [PATCH net-next v4 1/1] af_unix: Do not wait for garbage
 collector in sendmsg()
Message-ID: <20260807180709.6fb7f2b2@kernel.org>
In-Reply-To: <bc759ceba26d6e20fab3bcf7333ee7e6246696b6.1785824313.git.namcao@linutronix.de>
References: <cover.1785824313.git.namcao@linutronix.de>
	<bc759ceba26d6e20fab3bcf7333ee7e6246696b6.1785824313.git.namcao@linutronix.de>
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On Tue,  4 Aug 2026 08:46:16 +0200 Nam Cao wrote:
> AF_UNIX sockets' sendmsg() schedules and blocks on the garbage collector if
> user has too many inflight unix sockets and there is cyclic reference in
> the system. This causes real-time issues, as cyclic reference can be
> created by any task in the system, and high priority tasks who do need to
> send lots of AF_UNIX sockets get blocked by the garbage collector which
> runs as workqueue, causing a priority inversion scenario.

Hi Kuniyuki! Any thoughts?