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 X-Spam-Level: X-Spam-Status: No, score=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 46977C2D0DB for ; Fri, 31 Jan 2020 18:51:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F9E920CC7 for ; Fri, 31 Jan 2020 18:51:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725954AbgAaSvo (ORCPT ); Fri, 31 Jan 2020 13:51:44 -0500 Received: from mga03.intel.com ([134.134.136.65]:48951 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725939AbgAaSvo (ORCPT ); Fri, 31 Jan 2020 13:51:44 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Jan 2020 10:51:43 -0800 X-IronPort-AV: E=Sophos;i="5.70,386,1574150400"; d="scan'208";a="223229675" Received: from ajakowsk-mobl1.amr.corp.intel.com (HELO localhost.localdomain) ([10.78.25.164]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-SHA; 31 Jan 2020 10:51:43 -0800 Subject: Re: [PATCH 1/2] block: introduce polling on bio level To: Christoph Hellwig Cc: axboe@kernel.dk, song@kernel.org, linux-block@vger.kernel.org, linux-raid@vger.kernel.org, Artur Paszkiewicz References: <20200126044138.5066-1-andrzej.jakowski@linux.intel.com> <20200126044138.5066-2-andrzej.jakowski@linux.intel.com> <20200131063407.GB6267@infradead.org> From: Andrzej Jakowski Message-ID: <081badca-ab0f-f666-1e5e-71992f93a157@linux.intel.com> Date: Fri, 31 Jan 2020 11:51:43 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <20200131063407.GB6267@infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 1/30/20 11:34 PM, Christoph Hellwig wrote: > Can you explain this check? This looks weird to me I think we need > a generalized check if a make_request based driver supports REQ_NOWAIT > instead (and as a separate patch / patchset). Original check used to reject polled IO for stackable block devices as "not supported". To solve that situation I introduced additional check to reject all non REQ_HIPRI requests. That check is not intended to generalize, like you indicated, but to conservatively select which requests to accept. Perhaps there is better way to do that. Any suggestions?