On Wed, 23 Apr 2014 13:08:47 +0200 Jan Kara <j...@suse.cz> wrote: > > If you want reliable crash logging then we need to be able to set a > > printk level mask per console and just set the serial console for > > "crit/err" and the queue console for the rest, with a 'cat > > >/dev/ttywhatever' running if this feature was in use ? > Ok, now I understand. Thanks for an interesting idea. IMO people > definitely need messages logged directly into serial console when e.g. oops > is happening because very likely they won't get logged to disk and even > userspace won't have a chance to run and copy messages to the serial > console. Plus for useful softlockup reports or oops messages you need also > the KERN_NOTICE and KERN_INFO messages - stack traces, cpu numbers, process > information - all this is printed with these levels. > > These obvious places could be changed to print with lower log level I > assume but still I'm somewhat worried that some KERN_INFO messages that > would be useful for debugging a crash won't make it to console before the > crash happens. > > But if both you and Andrew think that the above problems are smaller than > the complexity connected with printk offloading, I can give it a try. > Andrew?
I'm curious about the idea of writing a new(?) console driver which the problematic machines can use. The problem of course will be in sizing the driver's queue. Perhaps we can have a driver which uses a huge queue, temporarily use that driver during boot then switch over to a conventional console driver? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
