Re: [PATCH net-next] tcp_metrics: hash table allocation cleanup

[Kuniyuki Iwashima <kuniyu@amazon.com>]

From: Eric Dumazet <edumazet@google.com>
Date: Thu,  3 Aug 2023 13:54:16 +0000
> After commit 098a697b497e ("tcp_metrics: Use a single hash table
> for all network namespaces.") we can avoid calling tcp_net_metrics_init()
> for each new netns.
> 
> Instead, rename tcp_net_metrics_init() to tcp_metrics_hash_alloc(),
> and move it to __init section.
> 
> Also move tcpmhash_entries to __initdata section.
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>


> ---
>  net/ipv4/tcp_metrics.c | 19 +++++++------------
>  1 file changed, 7 insertions(+), 12 deletions(-)
> 
> diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c
> index 82f4575f9cd90049a5ad4c7329ad1ddc28fc1aa0..96ab455063c57fd04c8d754ee623929d009ee716 100644
> --- a/net/ipv4/tcp_metrics.c
> +++ b/net/ipv4/tcp_metrics.c
> @@ -972,7 +972,7 @@ static struct genl_family tcp_metrics_nl_family __ro_after_init = {
>  	.resv_start_op	= TCP_METRICS_CMD_DEL + 1,
>  };
>  
> -static unsigned int tcpmhash_entries;
> +static unsigned int tcpmhash_entries __initdata;
>  static int __init set_tcpmhash_entries(char *str)
>  {
>  	ssize_t ret;
> @@ -988,15 +988,11 @@ static int __init set_tcpmhash_entries(char *str)
>  }
>  __setup("tcpmhash_entries=", set_tcpmhash_entries);
>  
> -static int __net_init tcp_net_metrics_init(struct net *net)
> +static void __init tcp_metrics_hash_alloc(void)
>  {
> +	unsigned int slots = tcpmhash_entries;
>  	size_t size;
> -	unsigned int slots;
>  
> -	if (!net_eq(net, &init_net))
> -		return 0;
> -
> -	slots = tcpmhash_entries;
>  	if (!slots) {
>  		if (totalram_pages() >= 128 * 1024)
>  			slots = 16 * 1024;
> @@ -1009,9 +1005,7 @@ static int __net_init tcp_net_metrics_init(struct net *net)
>  
>  	tcp_metrics_hash = kvzalloc(size, GFP_KERNEL);
>  	if (!tcp_metrics_hash)
> -		return -ENOMEM;
> -
> -	return 0;
> +		panic("Could not allocate the tcp_metrics hash table\n");
>  }
>  
>  static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_list)
> @@ -1020,7 +1014,6 @@ static void __net_exit tcp_net_metrics_exit_batch(struct list_head *net_exit_lis
>  }
>  
>  static __net_initdata struct pernet_operations tcp_net_metrics_ops = {
> -	.init		=	tcp_net_metrics_init,
>  	.exit_batch	=	tcp_net_metrics_exit_batch,
>  };
>  
> @@ -1028,9 +1021,11 @@ void __init tcp_metrics_init(void)
>  {
>  	int ret;
>  
> +	tcp_metrics_hash_alloc();
> +
>  	ret = register_pernet_subsys(&tcp_net_metrics_ops);
>  	if (ret < 0)
> -		panic("Could not allocate the tcp_metrics hash table\n");
> +		panic("Could not register tcp_net_metrics_ops\n");
>  
>  	ret = genl_register_family(&tcp_metrics_nl_family);
>  	if (ret < 0)
> -- 
> 2.41.0.640.ga95def55d0-goog