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 E1589C433E7 for ; Fri, 9 Oct 2020 11:26:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76CDA22269 for ; Fri, 9 Oct 2020 11:26:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="mZnwceWe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388081AbgJIL0q (ORCPT ); Fri, 9 Oct 2020 07:26:46 -0400 Received: from mx2.suse.de ([195.135.220.15]:59784 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731442AbgJIL0p (ORCPT ); Fri, 9 Oct 2020 07:26:45 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1602242804; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=SuCMHls48f4xLMwBK0m/Wzqo51WwaFK9373PeeO+uwo=; b=mZnwceWeAenutkEypdAM2WaVtaYclewuw0N8vBzN3RFN+NdfP5m15ymsCxtfWUHeQ+5T5M uvSTSKHgfpjweQO57N5YesKoet2VB09b7VbqL0XLC4stJTimcTQi0Imr/+rsXkcySbdszv FiuFvpPuThPxXoTiQnYfliujgb+FRyI= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 50C14AC84; Fri, 9 Oct 2020 11:26:44 +0000 (UTC) Date: Fri, 9 Oct 2020 13:26:43 +0200 From: Michal Hocko To: Peter Zijlstra Cc: Thomas Gleixner , Frederic Weisbecker , LKML , Mel Gorman , Ingo Molnar Subject: Re: [RFC PATCH] kernel: allow to configure PREEMPT_NONE, PREEMPT_VOLUNTARY on kernel command line Message-ID: <20201009112643.GM4967@dhcp22.suse.cz> References: <20201007120401.11200-1-mhocko@kernel.org> <20201007122144.GF2628@hirez.programming.kicks-ass.net> <20201007123553.GK29020@dhcp22.suse.cz> <20201009094741.GH2628@hirez.programming.kicks-ass.net> <20201009101405.GI4967@dhcp22.suse.cz> <20201009102009.GK2628@hirez.programming.kicks-ass.net> <20201009104808.GK4967@dhcp22.suse.cz> <20201009111703.GL4967@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201009111703.GL4967@dhcp22.suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 09-10-20 13:17:04, Michal Hocko wrote: [...] > +config PREEMPT_DYNAMIC > + bool "Allow boot time preemption model selection" depends on !ARCH_NO_PREEMPT > + depends on PREEMPT_NONE || PREEMPT_VOLUNTARY > + help > + This option allows to define the preemption model on the kernel > + command line parameter and thus override the default preemption > + model defined during compile time. > + > + The feature is primarily interesting for Linux distributions which > + provide a pre-built kernel binary to reduce the number of kernel > + flavors they offer while still offering different usecases. > + > + The runtime overhead is negligible with JUMP_LABELS enabled but if > + runtime patching is not available for the specific architecture then > + the potential overhead should be considered. > + > + Select if you the same pre-built kernel should be used for both Server > + and Desktop workloads. > + > config PREEMPT_COUNT > bool -- Michal Hocko SUSE Labs