From: Jakub Kicinski <kuba@kernel.org>
To: Shuhao Tan <tanshuhao@google.com>
Cc: "David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Simon Horman <horms@kernel.org>,
Andrew Lunn <andrew+netdev@lunn.ch>,
Shuah Khan <shuah@kernel.org>,
Mina Almasry <almasrymina@google.com>,
Samiullah Khawaja <skhawaja@google.com>,
Kuniyuki Iwashima <kuniyu@google.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-kselftest@vger.kernel.org
Subject: Re: [PATCH net-next v1 0/2] Reuse threaded NAPI kthread across napi_del()/napi_add().
Date: Mon, 29 Jun 2026 16:26:19 -0700 [thread overview]
Message-ID: <20260629162619.55297244@kernel.org> (raw)
In-Reply-To: <20260629192029.4013794-1-tanshuhao@google.com>
On Mon, 29 Jun 2026 12:20:25 -0700 Shuhao Tan wrote:
> These drivers destroy and recreate queues during configuration
> changes. If a NAPI was threaded before destruction, during the
> creation, a new kthread will be spawned for the NAPI.
>
> Some drivers do not have this problem, e.g. netdevsim. But these
> drivers and the drivers mentioned above will still lose kthread
> during link flap (ndo_stop/ndo_open).
>
> Because the kthreads before and after these configuration changes are
> different, all the attributes associated with the kthread are lost.
> These include CPU mask, priority, scheduler policy, etc.. If the
> threaded state is preserved for a NAPI, it makes sense to want to
> preserve the attributes of the thread as well.
Send a netdev Netlink notification when NAPI is re-created and
let the userspace re-apply the settings? Keeping a few u32s
around is one thing but keeping a thread running and visible
in /procfs for the lifetime of a machine feels a little bit much.
IDK.
next prev parent reply other threads:[~2026-06-29 23:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-29 19:20 [PATCH net-next v1 0/2] Reuse threaded NAPI kthread across napi_del()/napi_add() Shuhao Tan
2026-06-29 19:20 ` [PATCH net-next v1 1/2] net: Save kthread of threaded NAPI in napi_config and restore it when trying to create a new kthread Shuhao Tan
2026-06-29 19:20 ` [PATCH net-next v1 2/2] selftests: net: Add kthread preserving test in napi_threaded and busy_poll_test Shuhao Tan
2026-06-29 23:26 ` Jakub Kicinski [this message]
2026-06-30 0:47 ` [PATCH net-next v1 0/2] Reuse threaded NAPI kthread across napi_del()/napi_add() Shuhao Tan
2026-06-30 1:19 ` Jakub Kicinski
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