lkml.org 
[lkml]   [2022]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [GIT PULL] printk for 5.20
    On 2022-08-03 09:08:07 [-0700], Linus Torvalds wrote:
    > But thinking some more about it, even the "serious RT" people almost
    > certainly don't really want some kind of static "disable it all". Not
    > even if it was a separate Kconfig question like I suggested.
    >
    > You'd most likely want it to be dynamic, because things like "log to
    > console" is different at bootup when the system hasn't started yet -
    > you can't really have realtime response when your hardware hasn't even
    > initialized yet - and when things are actually running.
    >
    > So I think even then you really just want a "turn off console logging"
    > dynamic flag, not a Kconfig option.

    Having such a flag would mean we have to set it starting with
    SYSTEM_SCHEDULING because otherwise we risk a deadlock once the console
    driver tries to acquire its lock. The printk code invokes the console
    drivers with disabled interrupts and the console driver use spinlock_t
    locking which become sleeping locks on PREEMPT_RT and must not be
    acquired with disabled interrupts.
    The long term solution is to have a printing thread for the console
    driver and the atomic console support to print directly in an emergency
    case.

    > Which I think we already have, in the form of log levels. No?
    >
    > Linus

    Sebastian

    \
     
     \ /
      Last update: 2022-08-03 18:36    [W:5.635 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site