A few days ago I had a very big problem with tc. On the machine tc is used in
many ways:
- from crontab to load night-time and day-time bandwidth (at 1am and 8am)
- from crontab to get statistics for qdiscs on WAN interfaces (every minute)
- from perl/php database for changing user bandwidth (sometimes)
What happened:
At 1am the night-time bandwidth should be loaded. tc hanged up, and also every
tc (for qdisc stats) loaded every minute from cron was waiting(?) for the
first one to finish its job. So the next day I had several hundreds tcs
running and I was unable to kill any of them. (loadavg 800 looks pretty bad).
reboot -f was the only solution (some other deamons stopped working and
everything was really slow).
The same thing happened about year ago on some other server. After it I added
some changes in qdisc stats script to check if there is any other tc running
and in that case don''t check qdisc stats and therefore don''t
run any more tc.
The similiraity between those two servers is that they have 2 processors. It
never happened to me on any other machine with 1 processor.
Current setup on which the problem appeared a few days ago is Linux 2.4.31,
iproute2-ss051107, iptables v1.3.2, Debian (probably testing, I''m not
maintaining the system).
Setup which caused probles ~year ago is Linux 2.4.28, iproute2-ss041019,
iptables v1.2.11, Slackware (mostly "current").
Kernels are heavy patched with p-o-m, imq and grsec.
Did anyone had similar problems?
And what is the difference between sources (.tar.gz):
iproute2-date_only
iproute2-2.6.X-date
iproute2-ssdate
?
In current setups I''m using iproute2-2.6.X-date.tar.gz, which results
in:
[root@XXX src]# ls | grep iproute
iproute2-2.6.14-051107
[root@XXX src]# ip -V
ip utility, iproute2-ss051107
and the log says:
Table to handle kernel paging request at virtual address ffffffe4
(http://tuxpowered.net/tc_lockup/log.txt)
Unfortunatly I don''t have System.map for this kernel anymore :(
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| Kajetan Staszkiewicz | JID: vegeta@chrome.pl |
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