From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EEAA7D2E9 for ; Wed, 8 Nov 2023 07:41:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Rro5imfK"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="AzsxTUEV" Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 54B5F1706 for ; Tue, 7 Nov 2023 23:41:38 -0800 (PST) From: Kurt Kanzenbach DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1699429295; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JvV0BBV98ILtpySlH9Oy5VCvWdR00btlLeloaBlnNPk=; b=Rro5imfKbpyGNO2QI7p1EbzRmMa1jAcE/6ktJe3prM5zfB8FbtlXRmrZwEdKCnlnEgGtMb 955LX4+LLPr48YVy7tV7guSEDx3JvD/9bw0LHBmWoIpYKxYw6nQSsfWVG7ilvJ2iHGFU5x 72zL16thJCeCY93depqNLSLBBa1wp4tX3pgaDIRlKUfjL48Ry3+TN+KaM72DnCqVkTDiNo DsvxwR16+RDJYfD+nt0dSQHe2DE9ji9/+sv3URuSbtS1chE2dz0tOGSq+mvQLxFKvm+zRc SXMa1Dskfs9J7M475Ts7XjGnoq9Br+sZHw1YpqJ+yvuyrlPGUNrOaCpagrPrGw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1699429295; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=JvV0BBV98ILtpySlH9Oy5VCvWdR00btlLeloaBlnNPk=; b=AzsxTUEVui+m87B8FzDkQqF6IEZUg7h7BzaNt2WZGkNGD+bquyueuCwsHIWncpA9s+A/Pk /E4vQ4yd87pHYYAQ== To: Florian Bezdeka , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, Sebastian Andrzej Siewior , jan.kiszka@siemens.com, vivek.behera@siemens.com Subject: Re: [PATCH net-next] net/core: Enable socket busy polling on -RT In-Reply-To: References: <20230523111518.21512-1-kurt@linutronix.de> <87zg033vox.fsf@kurt> Date: Wed, 08 Nov 2023 08:41:34 +0100 Message-ID: <87bkc44rpt.fsf@kurt> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain Hi Florian, On Mon Oct 30 2023, Florian Bezdeka wrote: >> > > Allow RX_BUSY_POLL on PREEMPT_RT if NETPOLL is disabled. Don't disable >> > > preemption on PREEMPT_RT within the busy poll loop. > > Sorry, I need one more information here: We try to re-use the kernel > and its configuration from Debian whenever possible. NETPOLL/NETCONSOLE > is build as module there. > > Will this limitation be addressed in the future? Is someone already > working on that? Is that maybe on the radar for the ongoing printk() > work? (Assuming printk() with NETCONSOLE enabled is the underlying > problem) > > We don't use NETPOLL/NETCONSOLE during runtime but it is enabled at > build time. Sadly we can not use busy polling mode in combination with > XDP now. (Ignoring the fact that we could adjust the kernel > configuration, build on our own, ...) > > Would love to hear your thoughts about that. Thanks a lot! Yes, the busy polling conflicts with netpoll due to the locking. At the moment you have to disable it in the kernel configuration and re-compile. I don't think anyone is working on solving this limitation yet. Thanks, Kurt --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJHBAEBCgAxFiEEvLm/ssjDfdPf21mSwZPR8qpGc4IFAmVLO64THGt1cnRAbGlu dXRyb25peC5kZQAKCRDBk9HyqkZzgpe9EACsA1Ztrm3UbfQhG+IvHsd0kuvKTQ1y rKlGmGl4XYhtDCISkvEqbVSYfhlpZgTDKXgbUccGZXWsQ81CJHVchEk5YAtkM1Qx xGWOWqqBbIYJWedznJ2kl7Zj3xsr4djI+K20vYt9nuDPOvjk1/HbZgsSwhZEiLoC 9s3bCkdPnMD0kpdYv0wqsi7d4zhhigDT7U7zWbNPLSet2WdPyiT1sThHp9h44YCH OFhTXapzo0tHO8o7TF7ZJluJ1qUZe2ZW+M/WRKy5Q8QYjZiuWZiH6BF5vU2Fs5zr ameT+FJW1tc+kTHqBGayE4NNDXFK6Dq+xwYVsSaPZw3SyWqelzaJfccQsEdUNIng T1MadFGpRJik9imaMfzJIIONPpo5cGb0ywl18r9yL4t7D9j/anWXtlWoYXYL+W/Z q2jnpfmSM9WYo8c0EpXlFq0ZvAEOaNuXjU+EJbYe1qfEnsu1iBzFMCZ71C3hg+1a 4KvzmhooUeCJWLbX1K9ufB/CFx7XoEF5TsoqSLkb8xx2DpJHrXyWTIaRyy8tL3H1 SkpP+Hy5tppow/tF56X/yMSaweh9CkT8IpWpYDnwzxLHY4pzuoRlo622cP7VNvTl nM/ElLCzBLDUSHi6OMZYLg3IqcWhJelT7nnkH7SKlGiDwldgzHmnQn61KQF/BVnM EQINhP4razNCqQ== =Xj6p -----END PGP SIGNATURE----- --=-=-=--