Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754155AbcJFIEs (ORCPT ); Thu, 6 Oct 2016 04:04:48 -0400 Received: from mail-oi0-f52.google.com ([209.85.218.52]:36177 "EHLO mail-oi0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752044AbcJFIEn (ORCPT ); Thu, 6 Oct 2016 04:04:43 -0400 MIME-Version: 1.0 In-Reply-To: <20161004191427.GG4205@htj.duckdns.org> References: <20161004132805.GB28808@redhat.com> <20161004155616.GB4205@htj.duckdns.org> <20161004162759.GD4205@htj.duckdns.org> <278BCC7B-ED58-4FDF-9243-FAFC3F862E4D@unimore.it> <20161004172852.GB73678@anikkar-mbp.local.dhcp.thefacebook.com> <20161004185413.GF4205@htj.duckdns.org> <20161004191427.GG4205@htj.duckdns.org> From: Linus Walleij Date: Thu, 6 Oct 2016 10:04:41 +0200 Message-ID: Subject: Re: [PATCH V3 00/11] block-throttle: add .high limit To: Tejun Heo Cc: Paolo Valente , Shaohua Li , Vivek Goyal , linux-block@vger.kernel.org, "linux-kernel@vger.kernel.org" , Jens Axboe , Kernel-team@fb.com, jmoyer@redhat.com, Mark Brown , Ulf Hansson Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1072 Lines: 32 On Tue, Oct 4, 2016 at 9:14 PM, Tejun Heo wrote: > I get that bfq can be a good compromise on most desktop workloads and > behave reasonably well for some server workloads with the slice > expiration mechanism but it really isn't an IO resource partitioning > mechanism. Not just desktops, also Android phones. So why not have BFQ as a separate scheduling policy upstream, alongside CFQ, deadline and noop? I understand the CPU scheduler people's position that they want one scheduler for everyone's everyday loads (except RT and SCHED_DEADLINE) and I guess that is the source of the highlander "there can be only one" argument, but note this: kernel/Kconfig.preempt: config PREEMPT_NONE bool "No Forced Preemption (Server)" config PREEMPT_VOLUNTARY bool "Voluntary Kernel Preemption (Desktop)" config PREEMPT bool "Preemptible Kernel (Low-Latency Desktop)" We're already doing the per-usecase Kconfig thing for preemption. But maybe somebody already hates that and want to get rid of it, I don't know. Yours, Linus Walleij