From: Qais Yousef <qais.yousef@arm.com> To: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <peterz@infradead.org>, Steven Rostedt <rostedt@goodmis.org>, Dietmar Eggemann <dietmar.eggemann@arm.com>, Pavan Kondeti <pkondeti@codeaurora.org> Cc: Juri Lelli <juri.lelli@redhat.com>, Vincent Guittot <vincent.guittot@linaro.org>, Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>, linux-kernel@vger.kernel.org, Qais Yousef <qais.yousef@arm.com> Subject: [PATCH v2 3/6] sched/rt: Optimize cpupri_find on non-heterogenous systems Date: Sun, 23 Feb 2020 18:39:58 +0000 [thread overview] Message-ID: <20200223184001.14248-4-qais.yousef@arm.com> (raw) In-Reply-To: <20200223184001.14248-1-qais.yousef@arm.com> By introducing a new cpupri_find_fitness() function that takes the fitness_fn as an argument and only called when asym_system static key is enabled. cpupri_find() is now a wrapper function that calls cpupri_find_fitness() passing NULL as a fitness_fn, hence disabling the logic that handles fitness by default. Reported-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Fixes: 804d402fb6f6 ("sched/rt: Make RT capacity-aware") LINK: https://lore.kernel.org/lkml/c0772fca-0a4b-c88d-fdf2-5715fcf8447b@arm.com/ Signed-off-by: Qais Yousef <qais.yousef@arm.com> --- kernel/sched/cpupri.c | 10 ++++++++-- kernel/sched/cpupri.h | 6 ++++-- kernel/sched/rt.c | 23 +++++++++++++++++++---- 3 files changed, 31 insertions(+), 8 deletions(-) diff --git a/kernel/sched/cpupri.c b/kernel/sched/cpupri.c index 1bcfa1995550..dd3f16d1a04a 100644 --- a/kernel/sched/cpupri.c +++ b/kernel/sched/cpupri.c @@ -94,8 +94,14 @@ static inline int __cpupri_find(struct cpupri *cp, struct task_struct *p, return 1; } +int cpupri_find(struct cpupri *cp, struct task_struct *p, + struct cpumask *lowest_mask) +{ + return cpupri_find_fitness(cp, p, lowest_mask, NULL); +} + /** - * cpupri_find - find the best (lowest-pri) CPU in the system + * cpupri_find_fitness - find the best (lowest-pri) CPU in the system * @cp: The cpupri context * @p: The task * @lowest_mask: A mask to fill in with selected CPUs (or NULL) @@ -111,7 +117,7 @@ static inline int __cpupri_find(struct cpupri *cp, struct task_struct *p, * * Return: (int)bool - CPUs were found */ -int cpupri_find(struct cpupri *cp, struct task_struct *p, +int cpupri_find_fitness(struct cpupri *cp, struct task_struct *p, struct cpumask *lowest_mask, bool (*fitness_fn)(struct task_struct *p, int cpu)) { diff --git a/kernel/sched/cpupri.h b/kernel/sched/cpupri.h index 32dd520db11f..efbb492bb94c 100644 --- a/kernel/sched/cpupri.h +++ b/kernel/sched/cpupri.h @@ -19,8 +19,10 @@ struct cpupri { #ifdef CONFIG_SMP int cpupri_find(struct cpupri *cp, struct task_struct *p, - struct cpumask *lowest_mask, - bool (*fitness_fn)(struct task_struct *p, int cpu)); + struct cpumask *lowest_mask); +int cpupri_find_fitness(struct cpupri *cp, struct task_struct *p, + struct cpumask *lowest_mask, + bool (*fitness_fn)(struct task_struct *p, int cpu)); void cpupri_set(struct cpupri *cp, int cpu, int pri); int cpupri_init(struct cpupri *cp); void cpupri_cleanup(struct cpupri *cp); diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c index 2c3fae637cef..e48d7c215aee 100644 --- a/kernel/sched/rt.c +++ b/kernel/sched/rt.c @@ -1504,7 +1504,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) * let's hope p can move out. */ if (rq->curr->nr_cpus_allowed == 1 || - !cpupri_find(&rq->rd->cpupri, rq->curr, NULL, NULL)) + !cpupri_find(&rq->rd->cpupri, rq->curr, NULL)) return; /* @@ -1512,7 +1512,7 @@ static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p) * see if it is pushed or pulled somewhere else. */ if (p->nr_cpus_allowed != 1 && - cpupri_find(&rq->rd->cpupri, p, NULL, NULL)) + cpupri_find(&rq->rd->cpupri, p, NULL)) return; /* @@ -1691,6 +1691,7 @@ static int find_lowest_rq(struct task_struct *task) struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask); int this_cpu = smp_processor_id(); int cpu = task_cpu(task); + int ret; /* Make sure the mask is initialized first */ if (unlikely(!lowest_mask)) @@ -1699,8 +1700,22 @@ static int find_lowest_rq(struct task_struct *task) if (task->nr_cpus_allowed == 1) return -1; /* No other targets possible */ - if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask, - rt_task_fits_capacity)) + /* + * If we're on asym system ensure we consider the different capacities + * of the CPUs when searching for the lowest_mask. + */ + if (static_branch_unlikely(&sched_asym_cpucapacity)) { + + ret = cpupri_find_fitness(&task_rq(task)->rd->cpupri, + task, lowest_mask, + rt_task_fits_capacity); + } else { + + ret = cpupri_find(&task_rq(task)->rd->cpupri, + task, lowest_mask); + } + + if (!ret) return -1; /* No targets found */ /* -- 2.17.1
next prev parent reply other threads:[~2020-02-23 18:40 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-02-23 18:39 [PATCH v2 0/6] RT Capacity Awareness Fixes & Improvements Qais Yousef 2020-02-23 18:39 ` [PATCH v2 1/6] sched/rt: cpupri_find: implement fallback mechanism for !fit case Qais Yousef 2020-02-23 18:39 ` [PATCH v2 2/6] sched/rt: Re-instate old behavior in select_task_rq_rt Qais Yousef 2020-02-25 15:21 ` Dietmar Eggemann 2020-02-26 11:34 ` Qais Yousef 2020-02-23 18:39 ` Qais Yousef [this message] 2020-02-23 18:39 ` [PATCH v2 4/6] sched/rt: allow pulling unfitting task Qais Yousef 2020-02-23 18:40 ` [PATCH v2 5/6] sched/rt: Better manage pushing unfit tasks on wakeup Qais Yousef 2020-02-24 6:10 ` Pavan Kondeti 2020-02-24 12:11 ` Qais Yousef 2020-02-24 16:04 ` Pavan Kondeti 2020-02-24 17:41 ` Qais Yousef 2020-02-25 3:55 ` Pavan Kondeti 2020-02-26 16:02 ` Qais Yousef 2020-02-27 3:36 ` Pavan Kondeti 2020-02-27 10:29 ` Qais Yousef 2020-02-23 18:40 ` [PATCH v2 6/6] sched/rt: Remove unnecessary assignment in inc/dec_rt_migration Qais Yousef 2020-02-23 23:16 ` Dietmar Eggemann 2020-02-24 12:31 ` Qais Yousef 2020-02-24 13:03 ` Dietmar Eggemann 2020-02-24 13:47 ` Qais Yousef
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