From owner-freebsd-hackers@freebsd.org Wed Sep 13 16:07:36 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 EA391E03279 for ; Wed, 13 Sep 2017 16:07:36 +0000 (UTC) (envelope-from asomers@gmail.com) 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 C72F06B813 for ; Wed, 13 Sep 2017 16:07:36 +0000 (UTC) (envelope-from asomers@gmail.com) Received: by mailman.ysv.freebsd.org (Postfix) id C31A5E03278; Wed, 13 Sep 2017 16:07:36 +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 C257AE03277 for ; Wed, 13 Sep 2017 16:07:36 +0000 (UTC) (envelope-from asomers@gmail.com) Received: from mail-lf0-x22b.google.com (mail-lf0-x22b.google.com [IPv6:2a00:1450:4010:c07::22b]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 473316B812 for ; Wed, 13 Sep 2017 16:07:36 +0000 (UTC) (envelope-from asomers@gmail.com) Received: by mail-lf0-x22b.google.com with SMTP id l196so1895044lfl.1 for ; Wed, 13 Sep 2017 09:07:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:sender:in-reply-to:references:from:date:message-id :subject:to:cc; bh=6gv/QkK4PMg+Lew1BRf18M+unKNfByaApZSM0kwUBg0=; b=bHAyglC2xlnUUBS69KYKN2KUTjvfT+2sw6tB5NKkt/jlvZ6uWoti8Mua57JohxMQBS lIQLZm7t1kLlD6ijyz7t3gAMeyM/raAccEYwMGBspZ2WZo5hcwXyAhMDQyv7T+wrGxn2 0Pi4J0nncxjINwALU/68hVlzi7N2tA6FhY2zOCyGs6ZQOYGxv+NUGGbaWx68tUZgI5Fa UGSfl2spwiCvWjUutlkl6hZXPd90qzQgonbnqKAlc0ZVx9a56zeaY7STVzoZsdVSi60O Qj3VxMip6AydiVeIGIfbb+K/3zEW60AOAMJnaV76ymPndVd7g1MxejYCpVqJBiB3JNZ/ k0FA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:sender:in-reply-to:references:from :date:message-id:subject:to:cc; bh=6gv/QkK4PMg+Lew1BRf18M+unKNfByaApZSM0kwUBg0=; b=pmbsJTwSJLbaui17uSjq2higyaOcT+1NEI30+Klx/IRKsQG0OTPod6B7+ssHmtunRM 6ulS74r3zMNbY44kIe7DHmNQLPHNJHDaBe88YYRhP1o/8CE80gNHov+sE+glELO211Tj yFPgxB9A04u163hYjdPPw7hDzjQjdae2zUnjxOpZp+O9yEHZRmzZZtSXcI7FF5q/k4/v EPm8Do5UCFrX4doC399ozaHKIcg/cdfR5UF3g6RLFkuIeKGx7WJxVpc7tOmh+j655EWa eQ3Gmw3yJEHj85a1KgXwdHfCLdyKMZKLOHMHyDx/Z0zadjEQY0ZWuiQQv/Nvnf0QB2im tyJw== X-Gm-Message-State: AHPjjUhApVWTGFgkThh9KIJ4SJ8V8VK4Mf/H63X05IFxlNU614KJFeRH zZDtndpS99GVmuafxX5X6LvP8tiZeuP0NWiEzso= X-Google-Smtp-Source: AOwi7QBJgfUYza7G8yMLUm0Pb8bpAXRtLWQkcgylpRQiSpp1jq55VBm92vlc3xByOL5Ue2uHjvVuHGyJnNg9Fji/kPU= X-Received: by 10.25.217.203 with SMTP id s72mr5748568lfi.68.1505318854191; Wed, 13 Sep 2017 09:07:34 -0700 (PDT) MIME-Version: 1.0 Sender: asomers@gmail.com Received: by 10.179.26.6 with HTTP; Wed, 13 Sep 2017 09:07:33 -0700 (PDT) In-Reply-To: <20170913155542.GA25871@mail.michaelwlucas.com> References: <20170913155542.GA25871@mail.michaelwlucas.com> From: Alan Somers Date: Wed, 13 Sep 2017 10:07:33 -0600 X-Google-Sender-Auth: 1gUYETpApJGr2N7vQ6EMU77a8z8 Message-ID: Subject: Re: required kernel rebuilds To: "Michael W. Lucas" Cc: "freebsd-hackers@freebsd.org" Content-Type: text/plain; charset="UTF-8" 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 16:07:37 -0000 On Wed, Sep 13, 2017 at 9:55 AM, Michael W. Lucas wrote: > 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? > > Thanks, > ==ml Enabling VIMAGE still requires a kernel rebuild, because of the possibility of crashes. I've seen such crashes on 10.2 or 10.3. I don't know if they're fixed in 11.1, but I haven't seen any yet. Changing MAXPHYS also requires a kernel rebuild. AFAIK MAXPHYS isn't related to any kernel crashes, but it does have performance implications. -Alan