> And the patch below, I added your signed-off-by if it looks good to you. Don't... > Here is the patch seems solve the problem, it looks all good in my box, my > only concern is how will this affect our RT code. > > >>From 8e4fa4e9a7b510bdaf90b8140ce1e847375abccf Mon Sep 17 00:00:00 2001 > From: Qiang Huang <h.huangqiang@xxxxxxxxxx> > Date: Thu, 25 Apr 2013 10:22:01 +0800 > Subject: [PATCH] sched: don't clear PF_THREAD_BOUND in select_fallback_rq > > 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> > Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx> You shoudn't have added my SOB... I didn't write this patch and I didn't even sugguest this fix or check if this is a correct fix. Please read Documentation/SubmittingPatches to learn how SOB should be used. > --- > 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; > } > -- 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
