From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753195AbeBTQ1g (ORCPT ); Tue, 20 Feb 2018 11:27:36 -0500 Received: from mga02.intel.com ([134.134.136.20]:37765 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752783AbeBTQ1d (ORCPT ); Tue, 20 Feb 2018 11:27:33 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.46,540,1511856000"; d="scan'208";a="176701489" Date: Tue, 20 Feb 2018 09:27:37 -0700 From: Keith Busch To: Peter Zijlstra Cc: Nitesh Shetty , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, linux-block@vger.kernel.org, axboe@fb.com, linux-nvme@lists.infradead.org, joshi.k@samsung.com Subject: Re: [PATCH] blk: optimization for classic polling Message-ID: <20180220162737.GC7076@localhost.localdomain> References: <3578876466-3733-1-git-send-email-nj.shetty@samsung.com> <20180220132137.GG25314@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180220132137.GG25314@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.9.1 (2017-09-22) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 20, 2018 at 02:21:37PM +0100, Peter Zijlstra wrote: > Also, set_current_state(TASK_RUNNING) is dodgy (similarly in > __blk_mq_poll), why do you need that memory barrier? You're right. The subsequent revision that was committed removed the barrier. The commit is here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit?id=67b4110f8c8d16e588d7730db8e8b01b32c1bd8b I hope the code at least looks more reasonable. The changelog isn't much different, though.