[CentOS] Strange content in the kernel dmesg traces

Tue Apr 24 22:26:22 UTC 2007
Mark Hull-Richter <mhullrich at gmail.com>

I am experimenting with the kernel (as some of you may know), and I
have added a whole slew of traces in some relatively sensitive code in
the lower levels of the page cache and i/o functions.  Most of this
tracing not only works but is highly revealing as to what the kernel
is doing and why.

However, I am now getting this odd content in the trace log (dmesg),
and I cannot figure out what it is or why it is there.  If anyone
recognizes this situation, I invite comment and suggestions on how to
eliminate or decipher it:

4296757675 pdflush(80): do_writepages: map>ops>wrtpgs ffffffffa0195ff5
4296757675 pdflush(80): mpage_writepages w/b index 49728 pages 256000
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7>__bio_add_page: 2x ph 88>128 || hw 88>88 || 360448>max
ffffffff802525d8 generic_make_request(bio 000001017c745300) 50729472, 704
__make_request(q 00000101b9293870, bio 000001017c745300: sdc; 50729600, 704)
ll_new_hw_segment: 70 + 29 > 88
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7><7>
<7><7><7><7>__bio_add_page: 2x ph 88>128 || hw 88>88 || 360448>max
ffffffff802525d8 generic_make_request(bio 000001017c745a80) 50730176, 704
__make_request(q 00000101b9293870, bio 000001017c745a80: sdc; 50730304, 704)
4296757684 swapper(0): dl_mv2dsp: sdc start 50710368 secs 1408

(The lines with the <7>s in them are long - I wrapped them for ease of
reading and to keep the width down somewhat.)

Or should I post this in the lkml?

Thanks.

-- 
Mark Hull-Richter, Linux Kernel Engineer
DATAllegro (www.datallegro.com)
85 Enterprise, Second Floor, Aliso Viejo, CA  92656
949-680-3082 - Office     949-330-7691 - fax