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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10201CD5BCB for ; Tue, 19 Sep 2023 14:25:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232792AbjISOZL convert rfc822-to-8bit (ORCPT ); Tue, 19 Sep 2023 10:25:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36058 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232801AbjISOZF (ORCPT ); Tue, 19 Sep 2023 10:25:05 -0400 Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2912EEA; Tue, 19 Sep 2023 07:24:56 -0700 (PDT) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.95) with esmtps (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1qibek-001CsS-ED; Tue, 19 Sep 2023 16:24:50 +0200 Received: from p5b13a40a.dip0.t-ipconnect.de ([91.19.164.10] helo=[192.168.178.81]) by inpost2.zedat.fu-berlin.de (Exim 4.95) with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (envelope-from ) id 1qibek-0024rB-4a; Tue, 19 Sep 2023 16:24:50 +0200 Message-ID: Subject: Re: Arches that don't support PREEMPT From: John Paul Adrian Glaubitz To: Peter Zijlstra Cc: Matthew Wilcox , Thomas Gleixner , Linus Torvalds , Ankur Arora , linux-kernel@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, mingo@redhat.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, mgorman@suse.de, rostedt@goodmis.org, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, boris.ostrovsky@oracle.com, konrad.wilk@oracle.com, jgross@suse.com, andrew.cooper3@citrix.com, Geert Uytterhoeven , linux-m68k@lists.linux-m68k.org, Richard Weinberger , Anton Ivanov , Johannes Berg , linux-um@lists.infradead.org, Brian Cain , linux-hexagon@vger.kernel.org, Richard Henderson , Ivan Kokshaysky , Matt Turner , linux-alpha@vger.kernel.org Date: Tue, 19 Sep 2023 16:24:48 +0200 In-Reply-To: <20230919141627.GB39281@noisy.programming.kicks-ass.net> References: <20230911150410.GC9098@noisy.programming.kicks-ass.net> <87h6o01w1a.fsf@oracle.com> <20230912082606.GB35261@noisy.programming.kicks-ass.net> <87cyyfxd4k.ffs@tglx> <87led2wdj0.ffs@tglx> <0e69f7df80dc5878071deb0d80938138d19de1d1.camel@physik.fu-berlin.de> <20230919134218.GA39281@noisy.programming.kicks-ass.net> <20230919141627.GB39281@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT User-Agent: Evolution 3.48.4 MIME-Version: 1.0 X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 91.19.164.10 X-ZEDAT-Hint: PO Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2023-09-19 at 16:16 +0200, Peter Zijlstra wrote: > > I find it a bit unfair that maintainers of architectures that have huge companies > > behind them use their manpower to urge less popular architectures for removal just > > because they don't have 150 people working on the port so they can keep up with > > design changes quickly. > > PREEMPT isn't something new. Also, I don't think the arch part for > actually supporting it is particularly hard, mostly it is sticking the > preempt_schedule_irq() call in return from interrupt code path. > > If you convert the arch to generic-entry (a much larger undertaking) > then you get this for free. If the conversion isn't hard, why is the first reflex the urge to remove an architecture instead of offering advise how to get the conversion done? Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer `. `' Physicist `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913