From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 81B704C3BE for ; Fri, 28 Jun 2024 12:59:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719579557; cv=none; b=TxMeD4WeiJYehRBcANu39uiDUxovAo5KRWe3MtgAjYiNq033ZKsb7jpuVWdGiGFuCCwq3vP4Cu/rDuRsCR0LsIIU349PjkfaosHQymk82jY1WGfzVwHkECR91H7tzrohCeit+rCqMNLtUleRw3RQbdzh9UkjY/+YvaGl86oaF6w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719579557; c=relaxed/simple; bh=AALzB7Je+dbwh9aqhaMZgSkeBrDEJ4ks1mzPpaq1yQU=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=q4aJt9JvGwBQBEtA8uBRsnIW2ZSgshSUc8tu/oGriVsFdxsfTpj+uWzJORMbIiDf+pMsx0y+JEt/Cf7ev/Ah2geoWNQLpuhFtjTpKHki1oDZ2qcMD/ieoA0LvnoxzkaZl7WWoW9OCsp2VzW4SSeG3ve0Dn15dzVdWSLUU5nX1W8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=DDwFXP0J; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="DDwFXP0J" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A098EC116B1; Fri, 28 Jun 2024 12:59:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1719579557; bh=AALzB7Je+dbwh9aqhaMZgSkeBrDEJ4ks1mzPpaq1yQU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DDwFXP0Jezjh6HwRwWyN4HiJxGhb1hSRwHt/ZYzmyzmOCyrPwU/rNrckD4px3ywZd E8odmGUnqgblI3gL/sdST1uqbx785TAEVx98PMpcJIwajUWnwnNy5io8K4FjqaZzh3 q7N3prYya54Qn95j3rXkErV9SKsVK1a23VS1VV9JXms5ID3YTy5TvnsEBu+bdVWdGY xhQCOLU+Cd1I2HZ1HUlg7ZE/g/4OVyLO7tuNZogKO7k4wF3fEDY/wALEmkRoctDL9H SidVEi+c01SgPB7yBsR0uqmON+sGOUc6WFtEY0lXT2QeKRNh6ewq+bznFm8KTCk2Pb uI5N+xPfkNc5w== Date: Fri, 28 Jun 2024 13:59:12 +0100 From: Simon Horman To: Kurt Kanzenbach Cc: Jesse Brandeburg , Tony Nguyen , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Sebastian Andrzej Siewior , Maciej Fijalkowski , Vinicius Costa Gomes , intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org Subject: Re: [PATCH iwl-next v2] igc: Get rid of spurious interrupts Message-ID: <20240628125912.GF783093@kernel.org> References: <20240611-igc_irq-v2-1-c63e413c45c4@linutronix.de> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240611-igc_irq-v2-1-c63e413c45c4@linutronix.de> On Fri, Jun 21, 2024 at 08:56:30AM +0200, Kurt Kanzenbach wrote: > When running the igc with XDP/ZC in busy polling mode with deferral of hard > interrupts, interrupts still happen from time to time. That is caused by > the igc task watchdog which triggers Rx interrupts periodically. > > That mechanism has been introduced to overcome skb/memory allocation > failures [1]. So the Rx clean functions stop processing the Rx ring in case > of such failure. The task watchdog triggers Rx interrupts periodically in > the hope that memory became available in the mean time. > > The current behavior is undesirable for real time applications, because the > driver induced Rx interrupts trigger also the softirq processing. However, > all real time packets should be processed by the application which uses the > busy polling method. > > Therefore, only trigger the Rx interrupts in case of real allocation > failures. Introduce a new flag for signaling that condition. > > [1] - https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=3be507547e6177e5c808544bd6a2efa2c7f1d436 > > Reviewed-by: Sebastian Andrzej Siewior > Acked-by: Vinicius Costa Gomes > Acked-by: Maciej Fijalkowski > Signed-off-by: Kurt Kanzenbach Reviewed-by: Simon Horman