linux - kjournald reasons for high usage

I'm trying to figure out why is
kjournald going crazy on my machine. It's an 8-core box with
loads of memory. It's got ~50% cpu load.

The
iotop doesn't seem to point at any specific processes - some bursts of writes here and
there (mostly cron starting, some monitoring stats generated, etc.) When I used
sys/vm/block_dump to gather the write statistics, I got lists
like this:

kjournald(1352):
            1909
sendmail(28934): 13
cron(28910): 12
cron(28912):
            11

munin-node(29015): 3
cron(28913):
            3
check_asterisk_(28917): 3
sh(28917):
            2
munin-node(29022): 2
munin-node(29021):
            2

Where
kjournald actions are just
WRITEs.

Why is that happening? What
else should I look at to limit the kjournald activity a bit? It seems disproportionate
to what's actually being written.