Date: Wed, 21 Feb 2018 10:18:07 -0800 (PST) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: cem@freebsd.org Cc: David Wolfskill <david@catwhisker.org>, current <current@freebsd.org>, Warner Losh <imp@freebsd.org> Subject: Re: Kernel selection in Lua loader Message-ID: <201802211818.w1LII7fh087166@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <CAG6CVpUxXgNe1ZoXrzthPcgO=SwDkg-4f-NyME=GTbvdLCiUjw@mail.gmail.com>
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> On Wed, Feb 21, 2018 at 6:11 AM, Kyle Evans <kevans@freebsd.org> wrote: > > On Wed, Feb 21, 2018 at 6:36 AM, David Wolfskill <david@catwhisker.org> wrote: > >> > >> ... > >> kernels="kernel kernel.old kernel.save" > >> > >> and the Forth loader presented (precisely) those kernels as the > >> available options for selecting a kernel to load and boot. > >> > > > > Right, so, we (and by we I mean cem@) actually implemented a form of > > auto-detection for kernels. Any directory in in /boot with a file > > named 'kernel' inside will be automatically listed, and that > > supplemented(*) 'kernels' and 'kernel' specified in loader.conf(5). > > > > (*) I use "supplemented" because I changed that in r329709, just a > > little bit ago, to not do the autodetection if a 'kernels' is > > explicitly set in loader.conf(5) My reasoning here is that there's > > probably a reason one has set it explicitly, whether it be to hide > > bogus kernels or just to slim down the list of kernels they need to > > cycle through. > > Yep. And to add a little more detail, because I like this behavior, > I've convinced Kyle to add a knob to re-enable the autodetection > behavior even in the presence of kernels="", by adding a > kernels_autodetect="yes" knob to loader.conf (r329733). Or how about parse a wildcard * in kernels= to mean do the same as kernels_autodetect=yes the should make it possible to control the order of them on the list bo doing something like kernels=/boot/kernel;/boot/kernel.old;*;/altboot/kernel;/altboot/kernel.GENERIC > Note that any kernels in kernels="" are offered first in the list, in > the same order as configured; any additional autodetected kernels > follow at the end (as you observed earlier): The mechansism now only allows autodetec at end, use of a wildcard to show when to insert autodetect allows a fairly arbitrary order. > >> with the Lua loader, I was being offered a choice among 4 kernels > >> (rather than the expected 3). Cycling through them (twice; I wanted > >> to be sure the behavior was reproducible), I noted that the presented > >> options were: > >> > >> * default/kernel > >> * kernel.old > >> * kernel.save > >> * kernel.panic > >> > >> (in that sequence). > > Best, > Conrad -- Rod Grimes rgrimes@freebsd.org
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