Date: Wed, 13 Sep 2017 10:07:33 -0600 From: Alan Somers <asomers@freebsd.org> To: "Michael W. Lucas" <mwlucas@michaelwlucas.com> Cc: "freebsd-hackers@freebsd.org" <hackers@freebsd.org> Subject: Re: required kernel rebuilds Message-ID: <CAOtMX2g6F9nb8xt-h=zWZHRsO9bFvyFaG-DXn9ki8NE49eQQhQ@mail.gmail.com> In-Reply-To: <20170913155542.GA25871@mail.michaelwlucas.com> References: <20170913155542.GA25871@mail.michaelwlucas.com>
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On Wed, Sep 13, 2017 at 9:55 AM, Michael W. Lucas <mwlucas@michaelwlucas.com> 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
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