Messages in this thread | | | Date | Wed, 20 Dec 2023 20:18:44 +0530 | Subject | Re: [PATCH] sched: move access of avg_rt and avg_dl into existing helper functions | From | Shrikanth Hegde <> |
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On 12/20/23 7:29 PM, Vincent Guittot wrote:
Hi Vincent, thanks for taking a look.
> On Wed, 20 Dec 2023 at 07:55, Shrikanth Hegde > <sshegde@linux.vnet.ibm.com> wrote: >> >> This is a minor code simplification. There are helper functions called >> cpu_util_dl and cpu_util_rt which gives the average utilization of DL >> and RT respectively. But there are few places in code where these >> variables are used directly. >> >> Instead use the helper function so that code becomes simpler and easy to >> maintain later on. >> >> Signed-off-by: Shrikanth Hegde <sshegde@linux.vnet.ibm.com> >> --- >> kernel/sched/fair.c | 12 +++++------- >> 1 file changed, 5 insertions(+), 7 deletions(-) >> >> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c >> index bcea3d55d95d..02631060ca7e 100644 >> --- a/kernel/sched/fair.c >> +++ b/kernel/sched/fair.c >> @@ -9212,19 +9212,17 @@ static inline bool cfs_rq_has_blocked(struct cfs_rq *cfs_rq) >> >> static inline bool others_have_blocked(struct rq *rq) >> { >> - if (READ_ONCE(rq->avg_rt.util_avg)) >> + if (cpu_util_rt(rq)) >> return true; >> >> - if (READ_ONCE(rq->avg_dl.util_avg)) >> + if (cpu_util_dl(rq)) >> return true; >> >> if (thermal_load_avg(rq)) >> return true; >> >> -#ifdef CONFIG_HAVE_SCHED_AVG_IRQ >> - if (READ_ONCE(rq->avg_irq.util_avg)) >> + if (cpu_util_irq(rq)) > > cpu_util_irq doesn't call READ_ONCE() >
I see. Actually it would be right if cpu_util_irq does call READ_ONCE no?
Sorry i havent yet understood the memory barriers in details. Please correct me if i am wrong here, since ___update_load_avg(&rq->avg_irq, 1) does use WRITE_ONCE and reading out this value using cpu_util_irq on a different CPU should use READ_ONCE no?
> >> return true; >> -#endif >> >> return false; >> } >> @@ -9481,8 +9479,8 @@ static unsigned long scale_rt_capacity(int cpu) >> * avg_thermal.load_avg tracks thermal pressure and the weighted >> * average uses the actual delta max capacity(load). >> */ >> - used = READ_ONCE(rq->avg_rt.util_avg); >> - used += READ_ONCE(rq->avg_dl.util_avg); >> + used = cpu_util_rt(rq); >> + used += cpu_util_dl(rq); >> used += thermal_load_avg(rq); >> >> if (unlikely(used >= max)) >> -- >> 2.39.3 >>
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