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Date:   Sun, 11 Oct 2020 12:18:03 -0700
From:   Jakub Kicinski <kuba@kernel.org>
To:     Xianting Tian <tian.xianting@h3c.com>
Cc:     <davem@davemloft.net>, <netdev@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] net: Avoid allocing memory on memoryless numa node
Message-ID: <20201011121803.2c003c7e@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com>
In-Reply-To: <20201011041140.8945-1-tian.xianting@h3c.com>
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On Sun, 11 Oct 2020 12:11:40 +0800 Xianting Tian wrote:
> In architecture like powerpc, we can have cpus without any local memory
> attached to it. In such cases the node does not have real memory.
> 
> Use local_memory_node(), which is guaranteed to have memory.
> local_memory_node is a noop in other architectures that does not support
> memoryless nodes.
> 
> Signed-off-by: Xianting Tian <tian.xianting@h3c.com>
> ---
>  net/core/dev.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 266073e30..dcb4533ef 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -2590,7 +2590,7 @@ static struct xps_map *expand_xps_map(struct xps_map *map, int attr_index,
>  		new_map = kzalloc(XPS_MAP_SIZE(alloc_len), GFP_KERNEL);
>  	else
>  		new_map = kzalloc_node(XPS_MAP_SIZE(alloc_len), GFP_KERNEL,
> -				       cpu_to_node(attr_index));
> +				       local_memory_node(cpu_to_node(attr_index)));
>  	if (!new_map)
>  		return NULL;
>  

Are we going to patch all kmalloc_node() callers now to apply
local_memory_node()?  Can't the allocator take care of this?