[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <59224c52-1864-4920-8bac-9da308d257db@linux.ibm.com>
Date: Mon, 25 Mar 2024 10:42:05 +0530
From: Shrikanth Hegde <sshegde@...ux.ibm.com>
To: Qais Yousef <qyousef@...alina.io>
Cc: mingo@...nel.org, peterz@...radead.org, vincent.guittot@...aro.org,
dietmar.eggemann@....com, linux-kernel@...r.kernel.org,
vschneid@...hat.com, qperret@...gle.com
Subject: Re: [PATCH v2 2/2] sched/fair: Use helper functions to access
rd->overload
On 3/24/24 6:46 AM, Qais Yousef wrote:
> On 03/22/24 19:46, Shrikanth Hegde wrote:
>>
>> if (!env->sd->parent) {
>> /* update overload indicator if we are at root domain */
>> - if (READ_ONCE(env->dst_rq->rd->overload) != (sg_status & SG_OVERLOAD))
>> - WRITE_ONCE(env->dst_rq->rd->overload, sg_status & SG_OVERLOAD);
>> + if (is_rd_overloaded(env->dst_rq->rd) != (sg_status & SG_OVERLOAD))
>> + set_rd_overload_status(env->dst_rq->rd,
>> + sg_status & SG_OVERLOAD);
>
> A bit picky, but..
>
> Wouldn't it be better to encapsulate the check of whether we're writing a new
> value inside set_rd_overload_status()? Only write if it the value changed and
> all future users wouldn't care then.
>
> I think no need to wrap the line too.
>
Yes. Makes sense all the places do the check and update, can be wrapped.
I will send out v3.
>>
>> /* Update over-utilization (tipping point, U >= 0) indicator */
>> set_rd_overutilized_status(env->dst_rq->rd,
>> @@ -12344,7 +12345,7 @@ static int sched_balance_newidle(struct rq *this_rq, struct rq_flags *rf)
>> rcu_read_lock();
>> sd = rcu_dereference_check_sched_domain(this_rq->sd);
>>
>> - if (!READ_ONCE(this_rq->rd->overload) ||
>> + if (!is_rd_overloaded(this_rq->rd) ||
>> (sd && this_rq->avg_idle < sd->max_newidle_lb_cost)) {
>>
>> if (sd)
>> @@ -2518,8 +2528,8 @@ static inline void add_nr_running(struct rq *rq, unsigned count)
>>
>> #ifdef CONFIG_SMP
>> if (prev_nr < 2 && rq->nr_running >= 2) {
>> - if (!READ_ONCE(rq->rd->overload))
>> - WRITE_ONCE(rq->rd->overload, 1);
>> + if (!is_rd_overloaded(rq->rd))
>> + set_rd_overload_status(rq->rd, 1);
>
> While at it, could you write SG_OVERLOAD instead of 1?
Done.
>
> Both patches LGTM otherwise
>
> Reviewed-by: Qais Yousef <qyousef@...alina.io>
>
>
Powered by blists - more mailing lists