Re: [PATCH RESEND]mm/ia64: fix a node distance bug
From: David Rientjes
Date: Fri Sep 07 2012 - 18:58:59 EST
On Thu, 6 Sep 2012, wujianguo wrote:
> From: Jianguo Wu <wujianguo@xxxxxxxxxx>
>
> In arch ia64, has following definition:
> extern u8 numa_slit[MAX_NUMNODES * MAX_NUMNODES];
> #define node_distance(from,to) (numa_slit[(from) * num_online_nodes() + (to)])
>
> num_online_nodes() is a variable value, it can be changed after hot-remove/add
> a node.
>
> I my practice, I found node distance is wrong after offline
> a node in IA64 platform. For example system has 4 nodes:
> node distances:
> node 0 1 2 3
> 0: 10 21 21 32
> 1: 21 10 32 21
> 2: 21 32 10 21
> 3: 32 21 21 10
>
> linux-drf:/sys/devices/system/node/node0 # cat distance
> 10 21 21 32
> linux-drf:/sys/devices/system/node/node1 # cat distance
> 21 10 32 21
>
> After offline node2:
> linux-drf:/sys/devices/system/node/node0 # cat distance
> 10 21 32
> linux-drf:/sys/devices/system/node/node1 # cat distance
> 32 21 32 --------->expected value is: 21 10 21
>
>
> Signed-off-by: Jianguo Wu <wujianguo@xxxxxxxxxx>
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxx>
Acked-by: David Rientjes <rientjes@xxxxxxxxxx>
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