From: Peter Zijlstra <peterz@infradead.org>
To: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: mingo@redhat.com, valentin.schneider@arm.com,
dietmar.eggemann@arm.com, vincent.guittot@linaro.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] sched/fair: Add group_misfit_task load-balance type
Date: Mon, 19 Feb 2018 14:56:44 +0100 [thread overview]
Message-ID: <20180219135644.GG25181@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1518711654-23503-3-git-send-email-morten.rasmussen@arm.com>
On Thu, Feb 15, 2018 at 04:20:49PM +0000, Morten Rasmussen wrote:
> @@ -6733,9 +6758,12 @@ done: __maybe_unused
> if (hrtick_enabled(rq))
> hrtick_start_fair(rq, p);
>
> + update_misfit_status(p, rq);
> +
> return p;
>
> idle:
> + update_misfit_status(NULL, rq);
> new_tasks = idle_balance(rq, rf);
>
> /*
So we set a point when picking a task (or tick). We clear said pointer
when idle.
> @@ -7822,6 +7855,10 @@ static inline void update_sg_lb_stats(struct lb_env *env,
> */
> if (!nr_running && idle_cpu(i))
> sgs->idle_cpus++;
> +
> + if (env->sd->flags & SD_ASYM_CPUCAPACITY &&
> + !sgs->group_misfit_task_load && rq->misfit_task_load)
> + sgs->group_misfit_task_load = rq->misfit_task_load;
> }
>
> /* Adjust by relative CPU capacity of the group */
And we read said pointer from another CPU, without holding the
respective rq->lock.
What happens, if right after we set sgs->group_misfit_task_load, our
task decides to exit?
next prev parent reply other threads:[~2018-02-20 13:04 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-15 16:20 [PATCH 0/7] sched/fair: Migrate 'misfit' tasks on asymmetric capacity systems Morten Rasmussen
2018-02-15 16:20 ` [PATCH 1/7] sched: Add static_key for asymmetric cpu capacity optimizations Morten Rasmussen
2018-02-16 13:47 ` Peter Zijlstra
2018-02-16 15:41 ` Morten Rasmussen
2018-02-16 16:51 ` Peter Zijlstra
2018-02-19 11:49 ` Morten Rasmussen
2018-02-16 17:39 ` Quentin Perret
2018-02-16 17:43 ` Peter Zijlstra
2018-02-15 16:20 ` [PATCH 2/7] sched/fair: Add group_misfit_task load-balance type Morten Rasmussen
2018-02-19 13:56 ` Peter Zijlstra [this message]
2018-02-19 13:58 ` Peter Zijlstra
2018-02-20 16:01 ` Morten Rasmussen
2018-02-15 16:20 ` [PATCH 3/7] sched/fair: Consider misfit tasks when load-balancing Morten Rasmussen
2018-02-15 16:20 ` [PATCH 4/7] sched/fair: Avoid unnecessary balancing of asymmetric capacity groups Morten Rasmussen
2018-02-19 14:50 ` Peter Zijlstra
2018-02-19 14:53 ` Peter Zijlstra
2018-02-20 16:22 ` Morten Rasmussen
2018-02-19 15:10 ` Peter Zijlstra
2018-02-20 16:33 ` Morten Rasmussen
2018-02-20 18:26 ` Peter Zijlstra
2018-02-23 16:38 ` Morten Rasmussen
2018-02-23 16:47 ` Peter Zijlstra
2018-02-26 15:06 ` Morten Rasmussen
2018-02-15 16:20 ` [PATCH 5/7] sched/fair: Kick nohz balance if rq->misfit_task Morten Rasmussen
2018-02-15 16:20 ` [PATCH 6/7] sched: Rename root_domain->overload to should_idle_balance Morten Rasmussen
2018-02-16 9:14 ` Juri Lelli
2018-02-16 9:49 ` Peter Zijlstra
2018-02-16 11:59 ` Valentin Schneider
2018-02-15 16:20 ` [PATCH 7/7] sched/fair: Set sd->should_idle_balance when misfit Morten Rasmussen
2018-02-28 7:46 ` [PATCH 0/7] sched/fair: Migrate 'misfit' tasks on asymmetric capacity systems Gaku Inami
2018-03-01 11:59 ` Valentin Schneider
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