Re: [PATCHSET] printk: implement printk_header() and merging printk, take #2

[Tejun Heo <htejun@gmail.com>]

Matthew Wilcox wrote:
> On Mon, Jan 21, 2008 at 02:13:52PM +0900, Tejun Heo wrote:
>> In a nutshell, printk_header() lets you do the following atomically
>> (against other messages).
>>
>>  code:
>>   printk(KERN_INFO "ata1.00: ", "line0\nline1\nline2\n");
>>
>>  output:
>>   <6>ata1.00: line0
>>   <6>         line1
>>   <6>         line2
> 
> I think this is a really bad idea.  It's much better to have:
> 
> <6>ata1.00: line0
> <6>ata1.00: line1
> <6>ata1.00: line2
> 
> That way you can grep for ata1.00 and get all messages relevant to that
> device.

It has some pros and cons.  Having indentation makes things easier on
human eyes but more difficult on scripts, but not too difficult -
indented lines can easily be matched with a bit of scripting.  Changing
the behavior is easy but I'm still inclined toward indentation because
printing header every line loses information about message boundaries.
Maybe there's a way to satisfy both like omitting the separator from the
second line on.

ata1.00: line0
ata1.00  line1
ata1.00  line2

Hmm... Any better ideas?

-- 
tejun