Messages in this thread | | | Date | Wed, 13 Feb 2013 07:18:53 +0100 | From | Damien Wyart <> | Subject | Re: [PATCH] sched: fix env->src_cpu for active migration |
| |
Hi,
I tested this on top of 3.8-rc7 and this made the machine (x86_64, Core i7 920) unable to boot (very early as nothing at all is displayed on screen). Nothing in the kernel log (after booting with a working kernel).
Double-checked by just backing out only this patch and this made the machine boot again.
Damien
> need_active_balance uses env->src_cpu which is set only if there is more > than 1 task on the run queue. We must set the src_cpu field unconditionnally > otherwise the test "env->src_cpu > env->dst_cpu" will always fail if there is > only 1 task on the run queue > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> > --- > kernel/sched/fair.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 81fa536..32938ea 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -5044,6 +5044,10 @@ redo: > > ld_moved = 0; > lb_iterations = 1; > + > + env.src_cpu = busiest->cpu; > + env.src_rq = busiest; > + > if (busiest->nr_running > 1) { > /* > * Attempt to move tasks. If find_busiest_group has found > @@ -5052,8 +5056,6 @@ redo: > * correctly treated as an imbalance. > */ > env.flags |= LBF_ALL_PINNED; > - env.src_cpu = busiest->cpu; > - env.src_rq = busiest; > env.loop_max = min(sysctl_sched_nr_migrate, busiest->nr_running); > > update_h_load(env.src_cpu);
| |