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Subject: Re: sched: restore sanity
From: Joe Perches <joe@perches.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: San Mehat <san@google.com>, Ingo Molnar <mingo@elte.hu>,
       Arjan van de Ven <arjan@infradead.org>,
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Date: Sun, 20 Dec 2009 09:22:23 -0800
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On Sun, 2009-12-20 at 16:19 +0100, Peter Zijlstra wrote:
> On Sun, 2009-12-20 at 07:05 -0800, San Mehat wrote:
> > >> Probably, but the rest is just as annoying, pr_* is crap.
> > Oh? Out of curiosity whats wrong with it?
> That's what should be asked of printk().

pr_<level> offers some things printk cannot:

o standardization, eliminates frequent missing KERN_ levels
  and missing/typo/misspelled module prefixes  
o visually shorter, fewer chars used, less 80 char wrapping
o finer grained ability to eliminate unnecessary messages
  for embedded systems
o standardized mechanism to prefix messages with module/function
o eventual code reduction via use of a singleton instead of
  duplicated module/function names
o eventual dynamic_debug styled control of prefix by
  module/function

There are quite of number of arbitrarily named module wrapper
macros and functions that build on printk.

Standardizing them around a fewer number of prefixes would
ease grepping for logging.

A standardized logging function to filter messages by
bitmask or level could also be useful. 

> We try to stick to ANSI-C as much as possible, we've got
> kalloc,kfree,strcmp,strnlen and all the other 'regular' C bits,
> deviating from that serves no purpose but seed confusion.

There is a lot of kernel code that isn't 'regular' C.

Nothing in pr_<level> is not ANSI-C, it just builds on printk.

> But I feel this has no place in the core kernel at all, esp when its
> getting in the way of things without offering a single benefit.

What are the negatives of using pr_<level>?


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