Messages in this thread | | | Date | Mon, 7 Jan 2008 12:09:04 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH] kthread: always create the kernel threads with normal priority |
| |
> > This causes a practical problem. When a runaway real-time task is > > eating 100% CPU and we attempt to put the CPU offline, sometimes we > > block while waiting for the creation of the highest-priority > > "kstopmachine" thread.
sched-devel.git has new mechanisms against runaway RT tasks. There's a new RLIMIT_RTTIME rlimit - if an RT task exceeds that rlimit then it is sent SIGXCPU.
there's also a new group scheduling extension that is driven via a sysctl:
/proc/sys/kernel/sched_rt_ratio
this way if a user has a runaway RT task, other users (and root) will still have some CPU time left. (in Peter's latest patchset that is replaced via rt_runtime_ns - but this is a detail)
so instead of the never-ending arms race of kernel thread priorities against RT task priorities, we are going towards making RT tasks safer on a policy level.
Ingo
| |