Messages in this thread | | | Date | Tue, 28 Apr 2020 17:45:32 +0200 | From | Michal Hocko <> | Subject | Re: [PATCH] printk: Add loglevel for "do not print to consoles". |
| |
On Tue 28-04-20 22:11:19, Tetsuo Handa wrote: > On 2020/04/28 21:18, Michal Hocko wrote: > > On Tue 28-04-20 20:33:21, Tetsuo Handa wrote: > >> On 2020/04/27 15:21, Sergey Senozhatsky wrote: > >>>> KERN_NO_CONSOLES is for type of messages where "saved for later analysis" is > >>>> important but "printed for immediate notification" is not important. > >>>> In other words, KERN_NO_CONSOLES is NOT for dying messages where "printed for > >>>> immediate notification" is important. > >>> > >>> per-console loglevel is a user configurable parameter. > >>> KERN_NO_CONSOLES is a hard-coded policy. > >> > >> But given that whether to use KERN_NO_CONSOLES is configurable via e.g. sysctl, > >> KERN_NO_CONSOLES will become a user configurable parameter. What's still wrong? > > > > How do I as a kernel developer know that KERN_NO_CONSOLES should be > > used? In other words, how can I assume what a user will consider > > important on the console? > > > > Existing KERN_$LEVEL allows a user to determine whether he/she wants that message > to be printed on consoles (even if it spams his/her operation doing on consoles), and > at the same time constrains that user whether that message is saved to log files. > KERN_NO_CONSOLES allows a user to control whether he/she wants that message to be > saved to log files (without spamming his/her operation doing on consoles).
I understand that. But how do I know whether the user considers the particular information important enough to be dumped on the console. This sounds like a policy in the kernel to me. I simply cannot forsee any console configuration to tell whether my information is going to swamp the console to no use or not. Compare that to KERN_$LEVEL instead. I know that an information is of low/high importance. It is the user policy to decide and base some filtering on top of that priority. -- Michal Hocko SUSE Labs
| |