From owner-svn-src-head@freebsd.org Fri Aug 19 08:50:45 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id EFA39BBE876; Fri, 19 Aug 2016 08:50:45 +0000 (UTC) (envelope-from tsoome@me.com) Received: from st13p35im-asmtp004.me.com (st13p35im-asmtp004.me.com [17.164.199.67]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id C39591ACC; Fri, 19 Aug 2016 08:50:45 +0000 (UTC) (envelope-from tsoome@me.com) Received: from process-dkim-sign-daemon.st13p35im-asmtp004.me.com by st13p35im-asmtp004.me.com (Oracle Communications Messaging Server 7.0.5.38.0 64bit (built Feb 26 2016)) id <0OC500H00EWOGM00@st13p35im-asmtp004.me.com>; Fri, 19 Aug 2016 08:50:39 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=me.com; s=4d515a; t=1471596639; bh=Qn2zRAbUldPkiw3VAJBhJSvOLsuK4ZF7r/VRJIhyp14=; h=Content-type:MIME-version:Subject:From:Date:Message-id:To; b=bpQv2ld4eAm/smsz3OUEU+tTMtRxJ83gl5gBN/ey78sOezV7Srq66mDWb6tb3IxO0 JXOa+Rx2WTeDS9R8jdnNGqyXh6f1sBmqLjJhi1BcUgCv3mjwo7WuPlm+m/cWoT4PDy UGmDs356ElYkijpRyd8Ylt9+EBIXW+pt0i3uuTXsLjlizNI8SL2GxezIAh7VJhC6QK X64JnvWCUeFMnjZieH9SSQH1xXkExQaEcafwDjc46Cr72+iG9Cdlo5MidtzGBsYeUX QvlJxztq3g7B1OIebA1rVxXbbWZz49ElrSAAKDeEjpaAodimDi2O9lEx3gKxGhv1aX gc5DqWg5gWtpw== Received: from [88.196.10.181] (181-10-196-88.dyn.estpak.ee [88.196.10.181]) by st13p35im-asmtp004.me.com (Oracle Communications Messaging Server 7.0.5.38.0 64bit (built Feb 26 2016)) with ESMTPSA id <0OC5000O1F8BK040@st13p35im-asmtp004.me.com>; Fri, 19 Aug 2016 08:50:39 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2016-08-19_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 clxscore=1011 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1603290000 definitions=main-1608190115 Content-type: text/plain; charset=utf-8 MIME-version: 1.0 (Mac OS X Mail 9.3 \(3124\)) Subject: Re: svn commit: r304187 - in head: . share/man/man4 sys/conf sys/dev/mcd sys/modules sys/modules/mcd From: Toomas Soome In-reply-to: <20160819073955.GC83214@kib.kiev.ua> Date: Fri, 19 Aug 2016 11:50:35 +0300 Cc: Warner Losh , Julian Elischer , John Baldwin , src-committers , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" Content-transfer-encoding: quoted-printable Message-id: <50AAF049-C8A7-4C69-A206-C3983FFA7867@me.com> References: <201608152038.u7FKc2NL026330@repo.freebsd.org> <2065331.KaGOSftJhd@ralph.baldwin.cx> <0d6c2e45-e4da-9bb7-a50c-212135d9ac4f@freebsd.org> <20160819073955.GC83214@kib.kiev.ua> To: Konstantin Belousov X-Mailer: Apple Mail (2.3124) X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 19 Aug 2016 08:50:46 -0000 > On 19. aug 2016, at 10:39, Konstantin Belousov = wrote: >=20 > On Thu, Aug 18, 2016 at 09:28:57PM -0600, Warner Losh wrote: >> On Thu, Aug 18, 2016 at 12:50 AM, Julian Elischer = wrote: >>> On 16/08/2016 4:54 AM, John Baldwin wrote: >>>>=20 >>>> On Monday, August 15, 2016 08:38:02 PM John Baldwin wrote: >>>>>=20 >>>>> Author: jhb >>>>> Date: Mon Aug 15 20:38:02 2016 >>>>> New Revision: 304187 >>>>> URL: https://svnweb.freebsd.org/changeset/base/304187 >>>>>=20 >>>>> Log: >>>>> Remove the mcd(4) driver for Mitsumi CD-ROM players. >>>>> This is a driver for a pre-ATAPI ISA CD-ROM adapter. As noted = in >>>>> the manpage, this driver is only useful as a backend to cdcontrol = to >>>>> play audio CDs since it doesn't use DMA, so its data performance = is >>>>> "abysmal" (and that was true in the mid 90's). >>>>=20 >>>> No one stepped up to test patches for it either when I last posted = patches >>>> to >>>> convert it from timeout(9) to callout(9). I have a few more = drivers that >>>> are >>>> both very old and that people have no business using in 12 (think = ISA >>>> adapters that don't do DMA and can't be used with pccard) that I = will be >>>> removing over the next little while. I brought up a list of = drivers on >>>> arch@ >>>> a couple of years ago and the conversation drifted off into the = weeds >>>> about >>>> trimming GENERIC, etc. No one objected to the specific drivers I = listed >>>> though (and I got a few pleas of "please remove"). If someone = shows up >>>> desperately clutching an ISA adapter they can always dig up the = source >>>> from >>>> svn and deal with forward porting it for whatever API changes have >>>> happened >>>> since it was removed. >>>=20 >>>=20 >>> I would imagine any machine still holding one of these probably has = not >>> enough memory to run FreeBSD. >>>=20 >>> would we still run in 2MB? >>=20 >> With insane levels of tuning, we can run in 32MB userland that can do >> things. Even 64MB is tight w/o some tuning. 16MB is almost certainly >> right out except for very specialized situations. 2MB? We can't even >> load the loader in that :(. Oh, and all these memory configs are only >> possible if you tweak the loader's block cache... >>=20 >=20 > 32MB is quite usable. Without any tuning, you get slightly less than = 10MB > for userspace, which is enough to for many things, and plenty if swap = is > added. >=20 > Note that you cannot boot on such configurations since loader was = broken, > but if you do manage to jump to kernel, things were fine several = months > ago. I tested my relatively recent OOM changes on 32MB qemu config. >> Warner >=20 If the target is to go as low memory as possible, sure, you can strip = all off, from boot loader point, you should load kernel from stage2 and = not use loader at all (you can load and jump kernel even now from = stage2, assuming it wont need any special configuration from loader = config) etc etc. This means highly specialized build and has nothing to = do with generic all purpose system. Also at some point, there is an question about how reasonable it is to = have such configuration as part of generic code base for special bits = like boot loader itself, as the problem is, testing all those variants = is becoming impossible and even keeping reasonable code base in all of = the #if #else #endif spaghetti is getting quite hard and error prone. =46rom developers point of view, it is not really encouraging to have = possible feedback like =E2=80=9Coh, but you did break my 32MB system = boot=E2=80=9D ;) This does bring back some memories however. For first 2 = unix systems I was dealing with, one had 8MB and another had 12MB of = memory=E2=80=A6 it was ~ 1992-1993;) Right now the loader and stage2 are set to use 64MB heap to make it = possible to implement zfs feature support and later on, for more = features. Also note that UEFI setups are much harder to deal with regard of memory = management, because as long as BS are in control, you can not really = control the memory management there and can end up with fragmented = unusable (for kernel loading) layout. This is especially nasty as = apparently some (buggy) systems actually have runtime services using = boot services memory areas, so you can end up in setup where you can not = re-use BS memory and those chunks can be all over the low memory address = space=E2=80=A6=20 rgds, toomas=