On Thu, 20 May 2010, Nikita V. Youshchenko wrote: > > > Still questions: > > > > > > 1) why does that prevent klogd from working? > > > > Patch below. > > ... > > @@ -1084,18 +1084,8 @@ void release_console_mutex(void) > > #endif > > } > > console_locked = 0; > > - raw_spin_unlock_irqrestore(&logbuf_lock, flags); > > mutex_unlock(&console_mutex); > > Hmm... that lock is taken inside loop body, then control goes out of loop > at 'break' statement, and then, if this line is deteled, lock is still > held at function return. Looks wrong. Stupid me. Yes. Drop that line. > > > 3) I believe that 8250 serial driver is aware of preempt-rt. > > > Could you please comment on my "2.6.33.2-rt13: RFC: fix serial > > > console" post to linux-rt-users list > > > (http://eeek.borgchat.net/lists/linux-rt-users/msg05569.html) > > > > While that can work due to the trylock, it can introduce massive > > latencies just in case some driver reports a status change or what > > ever. > > Isn't it better just manually disable console (with 'quiet' kernel command > line option) when running in production? This may be recommended in proper > guidelines. No, anything which needs extra parameters for normal operation is wrong as it affects users. Adding a "I'm debugging, I don't care" flag for developers is the right thing to do. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
