Messages in this thread |  | | | Date | Wed, 12 Sep 2012 15:58:30 +0800 | | From | Alex Shi <> | | Subject | Re: [PATCH 2/2] sched: trigger_load_balance clean up |
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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.shi@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 >> } > >
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