Messages in this thread | | | Date | Fri, 5 Apr 2024 11:48:07 +0200 | Subject | Re: [PATCH 6/7] sched/fair: Remove on_null_domain() and redundant checks | From | Pierre Gondois <> |
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Hello Peter,
On 4/4/24 09:27, Peter Zijlstra wrote: > On Wed, Apr 03, 2024 at 05:05:38PM +0200, Pierre Gondois wrote: >> CPUs with a NULL sched domain are removed from the HKR_TYPE_SCHED >> isolation mask. The two following checks are equialent: >> - !housekeeping_runtime_test_cpu(cpu, HKR_TYPE_SCHED) >> - on_null_domain(rq) >> >> Remove on_null_domain() and the redundant checks. >> >> Signed-off-by: Pierre Gondois <pierre.gondois@arm.com> >> --- >> kernel/sched/fair.c | 18 ++++++------------ >> 1 file changed, 6 insertions(+), 12 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index 3e0f2a0f153f..9657c8f2176b 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -11830,11 +11830,6 @@ static void sched_balance_domains(struct rq *rq, enum cpu_idle_type idle) >> >> } >> >> -static inline int on_null_domain(struct rq *rq) >> -{ >> - return unlikely(!rcu_dereference_sched(rq->sd)); >> -} >> - >> #ifdef CONFIG_NO_HZ_COMMON >> /* >> * NOHZ idle load balancing (ILB) details: >> @@ -12040,7 +12035,7 @@ void nohz_balance_exit_idle(struct rq *rq) >> SCHED_WARN_ON(rq != this_rq()); >> >> /* If we're a completely isolated CPU, we don't play: */ >> - if (on_null_domain(rq)) >> + if (!housekeeping_runtime_test_cpu(cpu_of(rq), HKR_TYPE_SCHED)) >> return; >> >> if (likely(!rq->nohz_tick_stopped)) > > This seems broken, the whole null domain can happen with cpusets, but > this housekeeping nonsense is predicated on CPU_ISOLATION and none of > that is mandatory for CPUSETS.
ok right, I will try to remove this implicit dependency,
Regards, Pierre
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