From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752137AbcAFMn1 (ORCPT ); Wed, 6 Jan 2016 07:43:27 -0500 Received: from mail-ig0-f177.google.com ([209.85.213.177]:33290 "EHLO mail-ig0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751777AbcAFMnX (ORCPT ); Wed, 6 Jan 2016 07:43:23 -0500 Subject: Re: [PATCH] Add possibility to set /dev/tty number To: One Thousand Gnomes References: <20160104154305.GA24533@kroah.com> <568AA47D.6010604@gmail.com> <20160104171121.GA25961@kroah.com> <568ABCBD.3070909@gmail.com> <568C0DB5.8070200@gmail.com> <20160105204745.760727c1@lxorguk.ukuu.org.uk> Cc: Greg KH , Pierre Paul MINGOT , jslaby@suse.cz, linux-kernel@vger.kernel.org From: "Austin S. Hemmelgarn" Message-ID: <568D0BB6.30606@gmail.com> Date: Wed, 6 Jan 2016 07:42:30 -0500 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.5.0 MIME-Version: 1.0 In-Reply-To: <20160105204745.760727c1@lxorguk.ukuu.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Antivirus: avast! (VPS 160106-0, 2016-01-06), Outbound message X-Antivirus-Status: Clean Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016-01-05 15:47, One Thousand Gnomes wrote: >> This means that not including the VT subsystem resulted in a 128k >> reduction in runtime footprint, and having only half the number of VT's >> resulted in a 52k reduction. Assuming a linear correlation between the >> number of VT's and the runtime footprint of the subsystem, that means >> the subsystem itself incurs 26k of overhead, and each VT incurs >> approximately 1.6k of overhead. > > Doesn't seem an unreasonable value - so yes you've made an argument for > dynamically allocating the vt structures when they are first referenced. No, I've made an argument for finding some way to reduce the runtime impact of the VT subsystem. Dynamic allocation is one way to do that, but not the only way. In fact, there already appears to be some degree of allocation on demand for VT's (otherwise deallocvt has no point), just not for everything associated with the VT. I'd be willing to bet that almost everything that reasonably can be dynamically allocated already is, there is a bare minimum required for even a virtual device after all.