From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751391AbbJLJQI (ORCPT ); Mon, 12 Oct 2015 05:16:08 -0400 Received: from foss.arm.com ([217.140.101.70]:46289 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750858AbbJLJQF (ORCPT ); Mon, 12 Oct 2015 05:16:05 -0400 Date: Mon, 12 Oct 2015 10:16:02 +0100 From: Will Deacon To: Timur Tabi Cc: Robert Richter , Catalin Marinas , Robert Richter , Tirumalesh Chalamarla , lkml , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] arm64: Increase the max granular size Message-ID: <20151012091601.GA16124@arm.com> References: <1442944788-17254-1-git-send-email-rric@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 10, 2015 at 12:39:25PM -0500, Timur Tabi wrote: > On Tue, Sep 22, 2015 at 12:59 PM, Robert Richter wrote: > > > > -#define L1_CACHE_SHIFT 6 > > +#define L1_CACHE_SHIFT 7 > > #define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT) > > Would it be better if this were a Kconfig option, like it is on ARM32? > > http://lxr.free-electrons.com/source/arch/arm/include/asm/cache.h#L7 I don't think it adds anything, to be honest. We really want one kernel that runs everywhere and we don't (yet) have the SoC variation that exists on arch/arm/, so we may as well just keep it as big as it needs to be. Of course, if we start to get significant divergence between the minimum and maximum value and that in turn shows a non-trivial impact on kernel size and/or performance, then we could consider a Kconfig option but at that point we'd probably also need to consider whether there are alternative ways of providing this information to the kernel. If somebody really wants to change it for their particular kernel build, modifying the #define isn't exactly rocket science. Will