On Tue, Dec 23, 2014 at 10:13:24PM +0100, Bruno Prémont wrote: > On Tue, 23 December 2014 dwal...@fifo99.com wrote: > > On Sun, Dec 21, 2014 at 07:47:53PM +0100, Bruno Prémont wrote: > > > On Sat, 20 December 2014 dwal...@fifo99.com wrote: > > > > This adds to to the console= command line options allowing the > > > > addition of a per console log level setting. > > > > > > > > examples, > > > > > > > > console=ttyS0,ll4 > > > > console=tty0,ll6 > > > > > > > > This can be used on systems which have multiple serial consoles, but > > > > it's desired for logging to be light on one and heavy on another. > > > > > > Looks useful to me. > > > What would be the best way to make these per-console loglevels > > > configurable at runtime? `dmesg -n $LEVEL` only affects the global > > > limit. > > > > > > One drawback to letting global loglevel have precedence is that > > > all consoles that should not get detailed log messages need to have > > > their loglevel explicitly lowered and it's not possible to have > > > one console forced to show more than the global loglevel. > > > > Right, reason for the patch. > > > > > > > > An approach I would prefer is to have all consoles follow global > > > loglevel except when something different had been explicitly requested > > > for them. > > > > This patch is mostly like this. It breaks down when you set the "llX" > > parameter to something above KERN_NOTICE, and the global one is also > > set above that. > > In your patch global filter applies first, then what passes global filter > gets filtered with the per-console filter. > > So I can't have `dmesg -n 3` and "console=ttyS0,ll8 console=tty0" > to get my debugging output over serial console.
Yeah .. This would improve things. I changed it after I sent the first patch, but it looks like one of your patches changes it also. I was a little concerned about altering the fast path in call_console_drivers().. With the changes I made each call into call_console_drivers is forced to go thru the whole list of consoles, instead of short circuiting prior to the list. I was thinking the max local and global log level could be saved and used for short circuiting instead of using the global log level. > > > This way a single console can be added later on (e.g. netconsole) > > > and set to pass through debug messages without affecting anyone else. > > Netconsole console can be added at any time when system is running > either through loading of its module or using dynamic configuration > via configfs. > > See also my patches. Yeah, I saw them .. Not in too much detail, but it seems worth while for it to work with netconsole. Daniel -- 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/
