On Thu, Oct 8, 2020 at 3:15 PM Kyle Evans <kev...@freebsd.org> wrote: > > On Thu, Oct 8, 2020 at 1:02 PM Mitchell Horne <mho...@freebsd.org> wrote: > > > > Author: mhorne > > Date: Thu Oct 8 18:02:05 2020 > > New Revision: 366542 > > URL: https://svnweb.freebsd.org/changeset/base/366542 > > > > Log: > > Add a routine to dump boot metadata > > > > The boot metadata (also referred to as modinfo, or preload metadata) > > provides information about the size and location of the kernel, > > pre-loaded modules, and other metadata (e.g. the EFI framebuffer) to be > > consumed during by the kernel during early boot. It is encoded as a > > series of type-length-value entries and is usually constructed by > > loader(8) and passed to the kernel. It is also faked on some > > architectures when booted by other means. > > > > Although much of the module information is available via kldstat(8), > > there is no easy way to debug the metadata in its entirety. Add some > > routines to parse this data and allow it to be printed to the console > > during early boot or output via a sysctl. > > > > Since the output can be lengthly, printing to the console is gated > > behind the debug.dump_modinfo_at_boot kenv variable as well as the > > BOOTVERBOSE flag. The sysctl to print the metadata is named > > debug.dump_modinfo. > > > > Hi, > > Why both a tunable and boot -v? The tunable is already specifically > scoped to just this operation, it seems a little odd to double-gate > it. >
Hey Kyle, The original patch was gated behind just boot -v. In testing I realized this change is potentially quite noisy (even by bootverbose standards), so I added the tunable to make it opt-in. The thinking is that you could set debug.dump_modinfo_at_boot=1 once in loader.conf and forget it, as you wouldn't see the preload_dump() output on a normal boot. Thinking about it again, this might be overly complicated for what is at best a niche debugging feature. If gating it behind just the tunable is more in line with how other things work then I'm happy to change it. Mitchell > Thanks, > > Kyle Evans _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
