From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f72.google.com (mail-pg0-f72.google.com [74.125.83.72]) by kanga.kvack.org (Postfix) with ESMTP id 8ED926B0003 for ; Wed, 14 Feb 2018 04:59:15 -0500 (EST) Received: by mail-pg0-f72.google.com with SMTP id b6so1666214pgu.16 for ; Wed, 14 Feb 2018 01:59:15 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id l63-v6si8764547plb.565.2018.02.14.01.59.14 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 14 Feb 2018 01:59:14 -0800 (PST) Date: Wed, 14 Feb 2018 10:59:11 +0100 From: Michal Hocko Subject: Re: [patch 1/2] mm, page_alloc: extend kernelcore and movablecore for percent Message-ID: <20180214095911.GB28460@dhcp22.suse.cz> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Andrew Morton , Jonathan Corbet , Vlastimil Babka , Mel Gorman , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org On Mon 12-02-18 16:24:25, 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 '%'. I do not have any objections regarding the extension. What I am more interested in is _why_ people are still using this command line parameter at all these days. Why would anybody want to introduce lowmem issues from 32b days. I can see the CMA/Hotplug usecases for ZONE_MOVABLE but those have their own ways to define zone movable. I was tempted to simply remove the kernelcore already. Could you be more specific what is your usecase which triggered a need of an easier scaling of the size? -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org