Messages in this thread | | | Date | Fri, 25 Jul 2008 01:45:53 +0200 | From | Thomas Graf <> | Subject | Re: [PATCH] Traffic control cgroups subsystem |
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* Ranjit Manomohan <ranjitm@google.com> 2008-07-22 10:44 > The implementation consists of two parts: > > 1) A resource controller (cgroup_tc) that is used to associate packets from > a particular task belonging to a cgroup with a traffic control class id ( > tc_classid). This tc_classid is propagated to all sockets created by > tasks > in the cgroup and will be used for classifying packets at the link layer. > > 2) A modified traffic control classifier (cls_flow) that can classify > packets > based on the tc_classid field in the socket to specific destination > classes. > > An example of the use of this resource controller would be to limit > the traffic from all tasks from a file_server cgroup to 100Mbps. We could > achieve this by doing: > > # make a cgroup of file transfer processes and assign it a uniqe classid > # of 0x10 - this will be used lated to direct packets. > mkdir -p /dev/cgroup > mount -t cgroup tc -otc /dev/cgroup > mkdir /dev/cgroup/file_transfer > echo 0x10 > /dev/cgroup/file_transfer/tc.classid > echo $PID_OF_FILE_XFER_PROCESS > /dev/cgroup/file_transfer/tasks > > # Now create a HTB class that rate limits traffic to 100mbits and attach > # a filter to direct all traffic from cgroup file_transfer to this new > class. > tc qdisc add dev eth0 root handle 1: htb > tc class add dev eth0 parent 1: classid 1:10 htb rate 100mbit ceil 100mbit > tc filter add dev eth0 parent 1: handle 800 protocol ip prio 1 flow map key > cgroup-classid baseclass 1:10
It might have been easier to simply write a classifier which maps pids to classes. The interface could be as simple as two nested attributes, ADD_MAPS, REMOVE_MAPS which both take lists of pid->class mappings to either add or remove from the classifier.
I have been working on this over the past 2 weeks, it includes the classifier as just stated, a cgroup module which sends notifications about events as netlink messages and a daemon which creates qdiscs, classes and filters on the fly according to the configured distribution. It works both ingress (with some tricks) and egress.
IMHO, there is no point in a cgroup interface if the user has to create qdiscs, classes and filters manually anyway.
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