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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 25EEEC55179 for ; Thu, 29 Oct 2020 14:05:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B85D820825 for ; Thu, 29 Oct 2020 14:05:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="b35ci6In" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726212AbgJ2OFk (ORCPT ); Thu, 29 Oct 2020 10:05:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33226 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726044AbgJ2OFk (ORCPT ); Thu, 29 Oct 2020 10:05:40 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A1B2C0613D3; Thu, 29 Oct 2020 07:05:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=QFX/rG1nfZIO6l4gly+0bHosD8oEdLcUGfNyFPDeo2s=; b=b35ci6InfXu1GLmFPpVcMezq0t ngEwd6LKqAH04tvmf/uby22B13TxPisuejy+HoRD1GK0154yp/JZnQkum0Qw44N6IapT6WrhngL0E fdOHcJfJpb9ea4uvQg3Aggs8s8+6uYSAhBpmNXF+R6+6TTdb/o6ugVie9c/EmBhdetzSAN4BTt+K/ Ck9fPhw1BiqPr54xjrNlR/msky9ij4cjqUH2Q9LJw4yjVA6eeP0JOvjcxBzBDujEldGcYdYFGfetA FafwISEqui2jmvffxC2QshrHbl0fiZkJCzdr0ZekujAxZYQGxXlYBCk1AwL1c931+06NCsxIpS+1H E4l+d6oQ==; Received: from hch by casper.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1kY8Ya-0001mV-AN; Thu, 29 Oct 2020 14:05:36 +0000 Date: Thu, 29 Oct 2020 14:05:36 +0000 From: Christoph Hellwig To: Sebastian Andrzej Siewior Cc: linux-block@vger.kernel.org, Christoph Hellwig , Thomas Gleixner , David Runge , linux-rt-users@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org, Peter Zijlstra , Daniel Wagner , Mike Galbraith Subject: Re: [PATCH 3/3] blk-mq: Use llist_head for blk_cpu_done Message-ID: <20201029140536.GA6376@infradead.org> References: <20201028065616.GA24449@infradead.org> <20201028141251.3608598-1-bigeasy@linutronix.de> <20201028141251.3608598-3-bigeasy@linutronix.de> <20201029131212.dsulzvsb6pahahbs@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201029131212.dsulzvsb6pahahbs@linutronix.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org On Thu, Oct 29, 2020 at 02:12:12PM +0100, Sebastian Andrzej Siewior wrote: > Are there many drivers completing the SCSI requests in preemtible > context? In this case it would be more efficient to complete the request > directly (usb_stor_control_thread() goes to sleep after that anyway and > there is only one request at a time). Well, usb-storage obviously seems to do it, and the block layer does not prohibit it.