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> --- kernel/sched/core.c | 6 ------ 1 files changed, 0 insertions(+), 6 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 751ec60..8db6e3b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -1327,12 +1327,6 @@ out: } } - /* - * Clear PF_THREAD_BOUND, otherwise we wreckage - * migrate_disable/enable. See optimization for - * PF_THREAD_BOUND tasks there. - */ - p->flags &= ~PF_THREAD_BOUND; return dest_cpu; } -- 1.7.1 -- 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
