On May 4, 2013, at 23:38, Qiang Huang <h.huangqiang@xxxxxxxxxx> wrote: > On 2013/5/4 6:39, Luis Claudio R. Goncalves wrote: >> On Fri, May 03, 2013 at 10:46:10PM +0200, Sebastian Andrzej Siewior wrote: >> | * Qiang Huang | 2013-04-25 17:01:18 [+0800]: >> | >> | >This is revert of "sched-clear-pf-thread-bound-on-fallback-rq.patch" >> | >(commit 0d939066acdcb in v3.4-rt),. >> | > >> | >Select_fallback_rq() can be easilly called during system boot, because >> | >select_task_rq_fair() just return task_cpu(p) for bounded kernel threads, >> | >which is 0 during system boot and not in tsk_cpus_allowed, so >> | >select_fallback_rq() is called and PF_THREAD_BOUND is cleared. In my >> | >box, 1/3 bounded kernel threads will clear that flag after boot. >> | > >> | >And it will cause problems, for example: >> | ># for pid in `ps -e -o pid`; do taskset -p -c 0-15 $pid; done >> | >this command will cause system hung. >> | > >> | >What's more, I don't see why we need to clear this flag any more, >> | >because "cpu/rt: Rework cpu down for PREEMPT_RT" already remove the >> | >optimization for PF_THREAD_BOUND on migrate_disable/enable. >> | > >> | >Signed-off-by: Qiang Huang <h.huangqiang@xxxxxxxxxx> >> | >> | I can execute the command you mendtion above on v3.4 and v3.8 with no >> | hangs. Can you give me number of your cpus and maybe the config or >> | another detail? > > My cpu number is 16, and I think SMP is necessary for reproduce the > problem which should fit for most of us. > > But the config maybe an issue, with RT disabled, the problem is easy > to be reproduced, but with RT enabled, I do met an situation which can > not trigger the problem, and I haven't found the root cause yet, I have > both configs which can trigger the problem and not(with RT enabled), I > can send them to you privately if you need them. Your config - is it proprietary somehow that you cannot share it? -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
