Messages in this thread | | | Date | Wed, 27 Feb 2019 17:44:38 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH] printk/console: Do not suppress information about dropped messages |
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On (02/27/19 09:12), John Ogness wrote: > >> > >> My only objection to this is that the "messages dropped" only comes if a > >> non-supressed message comes. So information about dropped information > >> may never get printed unless some task prints something non-supressed. > >> > >> Imagine a situation where I am expecting a message to come, but don't > >> see it because it was dropped. But if no more non-supressed messages > >> come, I see neither the expected message nor the dropped message. > > > > I think this is exactly the problem (and thus the patch) we discussed > > some 3 years ago. > > I guess you are referring to this [0] thread.
Right.
[..] > I would agree with the proposed solution from 2016. My experience is > that the dropped messages are very important. Yes, printing them could > lead to the loss of even more messages.
Yes, printing out messages does take time. But I think it's easier to start losing messages due to preemption under console_sem than due to call_console_drivers() latencies.
> But still, it is important information that needs to get out.
I'd agree. A summary "you lost %d messages somewhere between current and previous messages" is surely better than what we have now, but is still a bit less informative than "you lost %d messages just now".
-ss
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