On 09/12/2012 02:36 AM, Suresh Siddha wrote: > On Mon, 2012-09-10 at 15:10 +0800, Alex Shi wrote: >> Remove a redundant check for on_null_domain(cpu), and rerange the code >> that make it more readable. > > hmm, but we are now doing the on_null_domain() check always, > irrespective of whether we need the load balance or not. > > do we really need the on_null_domain() check there? What happens if we > just remove it?
A very very simple try can not show removing causes crash. But as to RCU details, I don't know. :( CC to Paul > > thanks, > suresh > >> >> Signed-off-by: Alex Shi <alex....@intel.com> >> --- >> kernel/sched/fair.c | 8 +++++--- >> 1 files changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 5bbc4bf..529092d 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -4934,11 +4934,13 @@ static inline int on_null_domain(int cpu) >> void trigger_load_balance(struct rq *rq, int cpu) >> { >> /* Don't need to rebalance while attached to NULL domain */ >> - if (time_after_eq(jiffies, rq->next_balance) && >> - likely(!on_null_domain(cpu))) >> + if (unlikely(on_null_domain(cpu))) >> + return; >> + >> + if (time_after_eq(jiffies, rq->next_balance)) >> raise_softirq(SCHED_SOFTIRQ); >> #ifdef CONFIG_NO_HZ >> - if (nohz_kick_needed(rq, cpu) && likely(!on_null_domain(cpu))) >> + if (nohz_kick_needed(rq, cpu)) >> nohz_balancer_kick(cpu); >> #endif >> } > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/