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From: Peter Zijlstra <peterz@infradead.org>
To: Cruz Zhao <CruzZhao@linux.alibaba.com>
Cc: mingo@redhat.com, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] sched/core: Introduce nr_running percpu for each cookie
Date: Mon, 4 Jul 2022 11:45:18 +0200	[thread overview]
Message-ID: <YsK2riNersXeRgKM@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1656403045-100840-3-git-send-email-CruzZhao@linux.alibaba.com>

On Tue, Jun 28, 2022 at 03:57:24PM +0800, Cruz Zhao wrote:

>  static unsigned long sched_core_alloc_cookie(void)
>  {
>  	struct sched_core_cookie *ck = kmalloc(sizeof(*ck), GFP_KERNEL);
> +	int cpu;
> +
>  	if (!ck)
>  		return 0;
>  
>  	refcount_set(&ck->refcnt, 1);
> +
> +	ck->nr_running = alloc_percpu(unsigned int);

	if (!ck->nr_running)
		// do something

> +	for_each_possible_cpu(cpu)
> +		*per_cpu_ptr(ck->nr_running, cpu) = 0;

So I really, as in *really* dislike how this blows up the size of
cookies. Esp. with 100s of CPUs not actually being rare these days.

  parent reply	other threads:[~2022-07-04  9:45 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-28  7:57 [PATCH 0/3] sched/core: Optimize load balance of core scheduling Cruz Zhao
2022-06-28  7:57 ` [PATCH 1/3] sched/core: Fix the bug that task won't enqueue into core tree when update cookie Cruz Zhao
2022-07-03 14:19   ` cruzzhao
2022-07-04  8:53   ` Peter Zijlstra
2022-07-14 11:37     ` Peter Zijlstra
2022-07-15  5:08     ` cruzzhao
2022-07-21  8:44   ` [tip: sched/core] " tip-bot2 for Cruz Zhao
2022-06-28  7:57 ` [PATCH 2/3] sched/core: Introduce nr_running percpu for each cookie Cruz Zhao
2022-07-04  8:56   ` Peter Zijlstra
2022-07-04  9:45   ` Peter Zijlstra [this message]
2022-07-06  7:45     ` cruzzhao
2022-06-28  7:57 ` [PATCH 3/3] sched/core: Make tasks with the same cookie pairs on SMT siblings Cruz Zhao
2022-07-04  9:43   ` Peter Zijlstra
2022-07-06  8:03     ` cruzzhao

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