RE: [RFC PATCH 1/5] printk: implement pr_cont_t

From: David Laight
Date: Thu Aug 20 2020 - 08:33:35 EST


From: Petr Mladek
> Sent: 20 August 2020 11:16
...
> Now that I think about it. This is the biggest problem with any temporary buffer
> for pr_cont() lines. I am more and more convinced that we should just
> _keep the current behavior_. It is not ideal. But sometimes mixed
> messages are always better than lost ones.

Maybe a marker to say 'more expected' might be useful.
OTOH lack of a trailing '\n' probably signifies that a
pr_cont() is likely to be next.

Unexpected pr_cont() could be output with a leading "... "
to help indicate the message is a continuation.

> That said, some printk() API using local buffer would be still
> valuable for pieces of code where people really want to avoid
> mixed lines. But it should be optional and people should be
> aware of the risks.

That could be very useful if it supported multi-line output.
Thing like the stack backtrace code could use it avoid
the mess that happens when multiple processes generate
tracebacks at the same time.

David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)