Messages in this thread | | | Subject | Re: [PATCH] [request for inclusion] Realtime LSM | From | utz <> | Date | Tue, 11 Jan 2005 23:17:47 +0100 |
| |
On Tue, 2005-01-11 at 13:28 -0800, Matt Mackall wrote: > On Tue, Jan 11, 2005 at 12:47:07PM -0800, Chris Wright wrote: > > Guys, could we please bring this back to a useful discussion. None of > > you have commented on whether the rlimits for priority are useful. As I > > said before, I've no real problem with the module as it stands since it's > > tiny, quite contained, and does something people need. But I agree it'd > > be better to find something that's workable as long term solution. > > I almost like it. I don't like that it exposes the internal scheduler > priorities directly (-tiny in fact has options to change these!). So > perhaps some thought could be given to either stratifying it a bit > more (>2000 for SCHED_FIFO, >1000 for SCHED_RR, then SCHED_OTHER) or > separate limits for the different scheduling disciplines. > > Right now, you can make a good argument that SCHED_FIFO > SCHED_RR > > SCHED_OTHER from a privilege point of view, but that could change if > we add a pseudo-RT scheduling class of some sort. Similarly, adding a > discipline means adding an rlimit with the split approach, so that's > not very friendly either. > > Another way: > > 0-20: normal nice values (inverted) > >20: privilege to set any RT priority > > Limiting to below normal nice is a little weird and the offset to make > everything positive is weird as well. Above 20, any RT app can starve > SCHED_OTHER and it's less important to dole out fine-grained levels > here as these apps must be engineered to cooperate to some degree > anyway.
Limiting to positive nice values are needed too. At leased i need such thing. Normal users are only allowed to increase the nice value (lower prio). If a user job runs at nice 15 they can't renice it to 5. I get about 3 calls a week to do this as root.
And the presentation of the usual nice values can be done in userspace. pamlimits and ulimit already converts values (min -> s, KiB -> Bytes).
And separating the nice and RT part is useful to prevent confusion in userspace tools and for the admin.
I patched PAM which allows the setting of nice and realtime rlimits in limits.conf:
nice goes from 19 to -20 (internally converted to 0-39). realtime from 0 - 99.
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |