Re: [PATCH v2 01/13] x86: get pg_data_t's memory from other node

[Chen Gong]

On Tue, Apr 30, 2013 at 05:21:11PM +0800, Tang Chen wrote:
> Date: Tue, 30 Apr 2013 17:21:11 +0800
> From: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> To: mingo@xxxxxxxxxx, hpa@xxxxxxxxx, akpm@xxxxxxxxxxxxxxxxxxxx,
>  yinghai@xxxxxxxxxx, jiang.liu@xxxxxxxxxx, wency@xxxxxxxxxxxxxx,
>  isimatu.yasuaki@xxxxxxxxxxxxxx, tj@xxxxxxxxxx, laijs@xxxxxxxxxxxxxx,
>  davem@xxxxxxxxxxxxx, mgorman@xxxxxxx, minchan@xxxxxxxxxx,
>  mina86@xxxxxxxxxx
> Cc: x86@xxxxxxxxxx, linux-doc@xxxxxxxxxxxxxxx,
>  linux-kernel@xxxxxxxxxxxxxxx, linux-mm@xxxxxxxxx
> Subject: [PATCH v2 01/13] x86: get pg_data_t's memory from other node
> X-Mailer: git-send-email 1.7.10.1
> 
> From: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> 
> If system can create movable node which all memory of the
> node is allocated as ZONE_MOVABLE, setup_node_data() cannot
> allocate memory for the node's pg_data_t.
> So, use memblock_alloc_try_nid() instead of memblock_alloc_nid()
> to retry when the first allocation fails.
> 
> Signed-off-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
> Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
> Signed-off-by: Tang Chen <tangchen@xxxxxxxxxxxxxx>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
> ---
>  arch/x86/mm/numa.c |    5 ++---
>  1 files changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
> index 11acdf6..4f754e6 100644
> --- a/arch/x86/mm/numa.c
> +++ b/arch/x86/mm/numa.c
> @@ -214,10 +214,9 @@ static void __init setup_node_data(int nid, u64 start, u64 end)
>  	 * Allocate node data.  Try node-local memory and then any node.
>  	 * Never allocate in DMA zone.
>  	 */
> -	nd_pa = memblock_alloc_nid(nd_size, SMP_CACHE_BYTES, nid);
> +	nd_pa = memblock_alloc_try_nid(nd_size, SMP_CACHE_BYTES, nid);

go through the implementation of memblock_alloc_try_nid, it will call
panic when allocation fails(a.k.a alloc = 0), if so, below information
will be never printed. Do we really need this?

>  	if (!nd_pa) {
> -		pr_err("Cannot find %zu bytes in node %d\n",
> -		       nd_size, nid);
> +		pr_err("Cannot find %zu bytes in any node\n", nd_size);
>  		return;
>  	}
>  	nd = __va(nd_pa);
> -- 
> 1.7.1
> 
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