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

[Sergey Senozhatsky]

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?

> Otherwise, it looks nice:
> 
> Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>

Thanks.

	-ss