Received: by 2002:a05:6a10:9e8c:0:0:0:0 with SMTP id y12csp476733pxx; Thu, 29 Oct 2020 07:07:31 -0700 (PDT) X-Google-Smtp-Source: ABdhPJy1DsNYF/L6NkPxt5sCgGjR8OaMRUghKeNNILdC7hun6D4Bl+PR+BmZHMs7fOrKT9PqjC73 X-Received: by 2002:a05:6402:289:: with SMTP id l9mr4235400edv.294.1603980451090; Thu, 29 Oct 2020 07:07:31 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1603980451; cv=none; d=google.com; s=arc-20160816; b=Tlq9tONHSD+zSwTGixdt/wKKRUx3pm7+uuZFCBB/83bh31ApOrLCDwm/zMWczCXzbO aXBXUS9XKWalKaDu8fVAhLQOtWI6yEVrjmXAhbYLjbqqOPgVWCEL8qq1F916/cVDvKvn +g/w/QBMWx0AolproqopD4DBylEv+MNjG4+MYc9G/tysrfeC/cVWDIgssmME9Ko34hIO eO7SkyA1JFOogDGq7hpxAs8IISZp0epWGoNYUGjUO15TplQ4HYcgpzIiIo1jzg2v0879 J4Qul6K5ZjsqJHH7qIdOddqdh26rxXppkuj3hhqOB/BXuyBvF/VzmCA0yc4/84N5I075 oURQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:in-reply-to:content-disposition:mime-version :references:message-id:subject:cc:to:from:date:dkim-signature; bh=QFX/rG1nfZIO6l4gly+0bHosD8oEdLcUGfNyFPDeo2s=; b=QHLTCZzXX79DcyjoAF947Qra4ZJFpigoUT0YsQp+ELknADjlazjCAPWNZiTgfEDE2N L79fh7AVaSm0d9hSWYSeuvAUTk/pyuGfFthH1IQCiJHlJl/V/FAf2A8T9OiAzFua3SPB tyw3xHhMEMHUm3dkP9ftXciR9GW5zNkpBvlskYd9Ga4jYy8LtRK4K99SjUcI9yElrI+C zl/ZEiznj1Ru7Kpjo2ZVbRbZxYbryff/9ic4KDXL8jOLN2hu4HCxShLgcH7veSPdZR0X 8kfZ/Iy0dAxNPac3vqVHJ4FnQbC9CFGRFESXaviNdH9/v4t6m6NssqwBawQE9DVIj1XU eYhg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=b35ci6In; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id v7si2043198edw.389.2020.10.29.07.07.06; Thu, 29 Oct 2020 07:07:31 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=casper.20170209 header.b=b35ci6In; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726289AbgJ2OFk (ORCPT + 99 others); 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-kernel@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.