Re: [PATCHv2] printk: wake up klogd in vprintk_emit

[Petr Mladek]

On Fri 2018-04-20 10:52:21, Sergey Senozhatsky wrote:
> On (04/19/18 12:02), Petr Mladek wrote:
> > On Thu 2018-04-19 10:42:50, Sergey Senozhatsky wrote:
> > > We wake up klogd very late - only when current console_sem owner
> > > is done pushing pending kernel messages to the serial/net consoles.
> > > In some cases this results in lost syslog messages, because kernel
> > > log buffer is a circular buffer and if we don't wakeup syslog long
> > > enough there are chances that logbuf simply will wrap around.
> > > 
> > > The patch moves the klog wake up call to vprintk_emit(), which is
> > > the only legit way for a kernel message to appear in the logbuf,
> > > right before we attempt to grab the console_sem (possibly spinning
> > > on it waiting for the hand off) and call console drivers.
> > 
> > The last two lines need an update. What about?
> 
> Ah. Indeed!
> 
> > "right after the attempt to handle consoles. As a result, klog
> > will get waken either after flushing the new message to consoles
> > or immediately when consoles are still busy with older messages."
> 
> Looks good. Do you want me to resend the patch?

No need to resend. I could update the patch when pushing.

I'll wait few more days to give people time to respond.

Best Regards,
Petr