From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E7E5EC77B7D for ; Sat, 20 May 2023 04:29:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RSUeOTZAffF59T3jGSt/Qwrj01b3ZeGJAbfyxu27A9k=; b=T7V5I58b4e+SukvSgZPEwQxgZz YZ2AauvCD8nj+82VqxSwzL2DCCRdfyyKsy+xRppDtpbrqUhWVkdagnIBKDJCNQfelQlgMnzzas8mp EEROUJgvHXur2fRtUfcaGpSCFDzXwoL9Li7PzwCzsHnrG0dqxvCHitmq9hh5LBQApnJoTON8WHAJG nPvKh1jskES8XjycssNoDVPA/bw8wXZPPxMW9s53er227tpjfWU2Xo7aQhPqxEhO6fqj75oJHY+aX KQ5SVIk+zzXis2zlAqc5doqNGYDLF8kLxGsXsmP+6gamV/VZ4aNYO9YUah9S+PQ4FugkLA55n6iZJ 6zy+7Keg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1q0EDC-000fsi-1g; Sat, 20 May 2023 04:28:58 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1q0ED8-000frE-2m for linux-nvme@lists.infradead.org; Sat, 20 May 2023 04:28:56 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 71D1468CFE; Sat, 20 May 2023 06:28:51 +0200 (CEST) Date: Sat, 20 May 2023 06:28:51 +0200 From: Christoph Hellwig To: Uday Shankar Cc: Costa Sapuntzakis , Randy Jennings , Hannes Reinecke , Sagi Grimberg , Keith Busch , Christoph Hellwig , Jens Axboe , linux-nvme@lists.infradead.org Subject: Re: [PATCH v3 1/3] nvme: double KA polling frequency to avoid KATO with TBKAS on Message-ID: <20230520042851.GD31780@lst.de> References: <20230518183311.3224326-1-ushankar@purestorage.com> <20230518183311.3224326-2-ushankar@purestorage.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230518183311.3224326-2-ushankar@purestorage.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230519_212855_066587_228C41FD X-CRM114-Status: GOOD ( 13.87 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, May 18, 2023 at 12:33:09PM -0600, Uday Shankar wrote: > + * > + * When TBKAS is on, we need to run nvme_keep_alive_work at twice this > + * frequency, as one command completion can postpone sending a keep alive > + * command by up to twice the delay between runs. > */ > static void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl) > { > - queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ / 2); > + unsigned long delay = (ctrl->ctratt & NVME_CTRL_ATTR_TBKAS) ? > + ctrl->kato * HZ / 4 : ctrl->kato * HZ / 2; > + queue_delayed_work(nvme_wq, &ctrl->ka_work, delay); Kernel coding style wants an empty line after the variable declarations. I also find the style rather hard to read. Why not: unsigned long delay = ctrl->kato * HZ / 2; /* * When using Traffic Based Keep Alive, we need to run * nvme_keep_alive_work at twice the normal frequency, as one command * completion can postpone sending a keep alive command by up to * twice the delay between runs. */ if (ctrl->ctratt & NVME_CTRL_ATTR_TBKAS) delay /= 2; queue_delayed_work(nvme_wq, &ctrl->ka_work, delay); That's not quite as dense, but relaly gets the point across to the reader much better.