Re: [PATCH] Memoryless nodes: use "node_memory_map" for cpuset mems_allowed validation

[Nishanth Aravamudan <nacc@us.ibm.com>]

On 20.07.2007 [16:49:24 -0400], Lee Schermerhorn wrote:
> This fixes a problem I encountered testing Christoph's memoryless nodes
> series.  Applies atop that series.  Other than this, series holds up
> under what testing I've been able to do this week.
> 
> Memoryless Nodes:  use "node_memory_map" for cpusets mems_allowed validation
> 
> cpusets try to ensure that any node added to a cpuset's 
> mems_allowed is on-line and contains memory.  The assumption
> was that online nodes contained memory.  Thus, it is possible
> to add memoryless nodes to a cpuset and then add tasks to this
> cpuset.  This results in continuous series of oom-kill and other
> console stack traces and apparent system hang.
> 
> Change cpusets to use node_states[N_MEMORY] [a.k.a.
> node_memory_map] in place of node_online_map when vetting 
> memories.  Return error if admin attempts to write a non-empty
> mems_allowed node mask containing only memoryless-nodes.

Yep, in cursorily looking at the hugetlb pool growing with cpusets (more
specifically at cpuset.c), I was thinking this would be necessary.

> Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>

Acked-by: Nishanth Aravamudan <nacc@us.ibm.com>

Thanks,
Nish

-- 
Nishanth Aravamudan <nacc@us.ibm.com>
IBM Linux Technology Center

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