Kernel traces coming back with trash/clutter

[Mark Hull-Richter]

I am experimenting with the kernel (CentOSv4.4 x86_64, 2.6.9-42.0.10)
and I have added a number of traces in some relatively sensitive code
in the page cache and some i/o functions.

I am getting this odd content in the trace log (dmesg), and I cannot
figure out what it is or why it is there.

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.)

Any feedback that might illuminate this would be welcome.  Please CC
me personally as I am not yet able to subscribe to this list
(apologies).

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
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