linux-kernel - Re: [PATCH 2/2] percpu_counter: Put a reasonable upper bound on percpu_counter

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Date:	Fri, 26 Aug 2011 10:39:43 +0200
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Anton Blanchard <anton@...ba.org>
Cc:	tytso@....edu, adilger.kernel@...ger.ca, tj@...nel.org,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] percpu_counter: Put a reasonable upper bound on
 percpu_counter_batch

Le vendredi 26 août 2011 à 07:29 +1000, Anton Blanchard a écrit :

> +/*
> + * We set the batch at 2 * num_online_cpus(), with a minimum of 32 and
> + * a maximum of 1024.
> + */
>  static void compute_batch_value(void)
>  {
>  	int nr = num_online_cpus();
>  
> -	percpu_counter_batch = max(32, nr*2);
> +	percpu_counter_batch = min(1024, max(32, nr*2));
>  }
>  
>  static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,

Or use the following :

percpu_counter_batch = clamp(nr*2, 32, 1024);



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