[PATCH] net: Avoid allocing memory on memoryless numa node

[PATCH] net: Avoid allocing memory on memoryless numa node

[Xianting Tian]

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;
 
-- 
2.17.1

Re: [PATCH] net: Avoid allocing memory on memoryless numa node

[Jakub Kicinski]

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?

RE: [PATCH] net: Avoid allocing memory on memoryless numa node

[Tianxianting]

Hi Jakub,
Thanks for your suggestion,
Let me try it :-)

-----Original Message-----
From: Jakub Kicinski [mailto:kuba@kernel.org] 
Sent: Monday, October 12, 2020 3:18 AM
To: tianxianting (RD) <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

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?