From owner-freebsd-hackers@freebsd.org Wed Sep 13 23:26:33 2017 Return-Path: Delivered-To: freebsd-hackers@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 EBCC6E152AA for ; Wed, 13 Sep 2017 23:26:33 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from mailman.ysv.freebsd.org (mailman.ysv.freebsd.org [IPv6:2001:1900:2254:206a::50:5]) by mx1.freebsd.org (Postfix) with ESMTP id CF93E7F3B4 for ; Wed, 13 Sep 2017 23:26:33 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: by mailman.ysv.freebsd.org (Postfix) id CEDDDE152A7; Wed, 13 Sep 2017 23:26:33 +0000 (UTC) Delivered-To: hackers@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 CE676E152A5 for ; Wed, 13 Sep 2017 23:26:33 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from hz.grosbein.net (hz.grosbein.net [78.47.246.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "hz.grosbein.net", Issuer "hz.grosbein.net" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 60EB47F3B3 for ; Wed, 13 Sep 2017 23:26:32 +0000 (UTC) (envelope-from eugen@grosbein.net) Received: from eg.sd.rdtc.ru (root@eg.sd.rdtc.ru [62.231.161.221] (may be forged)) by hz.grosbein.net (8.15.2/8.15.2) with ESMTPS id v8DNQJBY079675 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Thu, 14 Sep 2017 01:26:20 +0200 (CEST) (envelope-from eugen@grosbein.net) X-Envelope-From: eugen@grosbein.net X-Envelope-To: mwlucas@michaelwlucas.com Received: from [10.58.0.4] ([10.58.0.4]) by eg.sd.rdtc.ru (8.15.2/8.15.2) with ESMTPS id v8DNQAkn004978 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NOT); Thu, 14 Sep 2017 06:26:10 +0700 (+07) (envelope-from eugen@grosbein.net) Subject: Re: required kernel rebuilds To: "Michael W. Lucas" , hackers@freebsd.org References: <20170913155542.GA25871@mail.michaelwlucas.com> From: Eugene Grosbein Message-ID: <59B9BE8D.5050807@grosbein.net> Date: Thu, 14 Sep 2017 06:26:05 +0700 User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 MIME-Version: 1.0 In-Reply-To: <20170913155542.GA25871@mail.michaelwlucas.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=2.2 required=5.0 tests=BAYES_00, LOCAL_FROM, RDNS_NONE autolearn=no autolearn_force=no version=3.4.1 X-Spam-Report: * -2.3 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * 2.6 LOCAL_FROM From my domains * 1.9 RDNS_NONE Delivered to internal network by a host with no rDNS X-Spam-Level: ** X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on hz.grosbein.net X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 13 Sep 2017 23:26:34 -0000 13.09.2017 22:55, Michael W. Lucas пишет: > Hi, > > Book research question. > > Way back in the Dark Ages of the 1990s, it wasn't uncommon to rebuild > a kernel to fix a recurring panic. You'd have to tune MAXUSERS, or > PMAP_SHPGPERPROC. > > AFAIK, dang near everything is tunable in either loader.conf or > sysctl.conf. I really want to say that kernel rebuilds for these kinds > of limits aren't needed any more. > > Does anyone have a counter-example, though? Is anything possibly > crash-inducing non-tunable without a kernel rebuild? Kernel stack overflow produce "double fault" panic and while i386 and amd64 platforms have loader tunnable kern.kstack_pages to increase this limit without need to rebuild the kernel, other platforms still do not have such tunnable and have kernel config file "options KSTACK_PAGES" only. See also https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219476 for details.