On Jan 23, 2008 8:48 AM, Andrea Righi <[EMAIL PROTECTED]> wrote: > > > > 1. Implementation of soft limits (limit on contention of resource) > > gets harder > > Why? do you mean implementing a grace time when the soft-limit is > exceeded? this could be done in cgroup_nl_throttle() introducing 3 > additional attributes to struct netlimit (i.e. hard_limit, > last_time_exceeded grace_time) and perform something like: > ... > if ((current_rate > hard_limit) || > time_after(jiffies, last_time_exceeded + grace_time)) > schedule_timeout(sleep); > ...
He's talking about cases where we want the behaviour to be work-conserving, whilst still offering guarantees in the event of contention. e.g. cgroups A and B each get a 20% guarantee on the TX path if they need it, but anyone can use any otherwise-idle bandwidth. (This is relatively straightforward to set up from userspace with the standard Linux traffic control tools). > > Yes, the integration with iptables (as Paul said), and traffic shaping > rules would be absolutely the right way(tm) in perspective. I was just > proposing a possible simple API to implement the limiting stuff. But this issue (traffic control for cgroups) is too complex to be described by a simple API. Any simple API you choose to try to describe the limiting directly will be insufficient for a good number of the potential users. Better to just provide a (very simple) API to hook into the existing (complex) traffic control API and leave the tricky stuff to userspace, where anyone can construct arbitrarily complex queueing schemes with a shell script and a few calls to "tc". Paul -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
