From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751918AbdI1IIC (ORCPT ); Thu, 28 Sep 2017 04:08:02 -0400 Received: from Galois.linutronix.de ([146.0.238.70]:55294 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751817AbdI1IIA (ORCPT ); Thu, 28 Sep 2017 04:08:00 -0400 Date: Thu, 28 Sep 2017 10:07:52 +0200 (CEST) From: Thomas Gleixner To: Peter Zijlstra cc: Anna-Maria Gleixner , LKML , Ingo Molnar , Christoph Hellwig , keescook@chromium.org, John Stultz Subject: Re: [PATCH 08/25] hrtimer: Reduce conditional code (expires_next, next_timer) In-Reply-To: <20170926121039.ov3i2k7dvg5iihfj@hirez.programming.kicks-ass.net> Message-ID: References: <20170831105725.809317030@linutronix.de> <20170831105826.196081352@linutronix.de> <20170926121039.ov3i2k7dvg5iihfj@hirez.programming.kicks-ass.net> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Sep 2017, Peter Zijlstra wrote: > On Thu, Aug 31, 2017 at 12:23:37PM -0000, Anna-Maria Gleixner wrote: > > The hrtimer_cpu_base struct member expires_next and next_timer are > > conditional members (CONFIG_HIGH_RES_TIMERS). This makes the hrtimer code > > more complex and harder to understand than it actually is. > > > > Reduce the conditionals related to those two struct members. > > So this grows the data structure for !HIGH_RES for easier code? We no > longer care about archs that don't support HIGH_RES? We care, but there is a tradeoff between the required conditional code and the marginal storage overhead. Easier to follow code which does a few superflous things for the !highres case is certainly preferred. Thanks, tglx