Re: [PATCH 5/6] mm: add some KERN_CONT markers to continuationlines

From: Joe Perches
Date: Wed Mar 02 2011 - 00:28:08 EST


On Tue, 2011-03-01 at 13:46 -0800, Linus Torvalds wrote:
> the concept of
> printk(KERN_CONT "\n")
> is just crazy: you're saying "I want to continue the line, in order to
> print a newline". Whaa?

It's a trivially useful "end of collected printk" mark,
which was made a bit superfluous by the code that added
any necessary newline before every KERN_<level>.

There are a thousand or so of them today.

$ grep -rP --include=*.[ch] "\b(printk\s*\(\s*KERN_CONT|pr_cont\s*\(|printk\s*\()\s*\"\\\n\"" * | wc -l
1061

That code made all message terminating newlines a bit
obsolete. I won't be submitting any patches to remove
those EOM newlines any time soon.

I hope no one does that.

It would be actually useful to have some form like:

cookie = collected_printk_start()
loop:
collected_printk(cookie, ...) (...)
collected_printk_end(cookie)

so that interleaved messages from multiple
concurrent streams could be sensibly collected
either post processed or buffered.

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