From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966153AbeBMXqL (ORCPT ); Tue, 13 Feb 2018 18:46:11 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36584 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966064AbeBMXqJ (ORCPT ); Tue, 13 Feb 2018 18:46:09 -0500 Date: Tue, 13 Feb 2018 15:46:07 -0800 From: Andrew Morton To: David Rientjes Cc: Jonathan Corbet , Vlastimil Babka , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org Subject: Re: [patch 1/2] mm, page_alloc: extend kernelcore and movablecore for percent Message-Id: <20180213154607.f631e2e033f42c32925e3d2d@linux-foundation.org> In-Reply-To: References: X-Mailer: Sylpheed 3.4.1 (GTK+ 2.24.23; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 12 Feb 2018 16:24:25 -0800 (PST) David Rientjes wrote: > Both kernelcore= and movablecore= can be used to define the amount of > ZONE_NORMAL and ZONE_MOVABLE on a system, respectively. This requires > the system memory capacity to be known when specifying the command line, > however. > > This introduces the ability to define both kernelcore= and movablecore= > as a percentage of total system memory. This is convenient for systems > software that wants to define the amount of ZONE_MOVABLE, for example, as > a proportion of a system's memory rather than a hardcoded byte value. > > To define the percentage, the final character of the parameter should be > a '%'. Is this fine-grained enough? We've had percentage-based tunables in the past, and 10 years later when systems are vastly larger, 1% is too much.