Re: [PATCH take3] Memoryless nodes: use "node_memory_map" for cpuset mems_allowed validation

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

On 24.07.2007 [16:30:19 -0400], Lee Schermerhorn wrote:
> Memoryless Nodes:  use "node_memory_map" for cpusets - take 3
> 
> Against 2.6.22-rc6-mm1 atop Christoph Lameter's memoryless nodes
> series
> 
> take 2:
> + replaced node_online_map in cpuset_current_mems_allowed()
>   with node_states[N_MEMORY]
> + replaced node_online_map in cpuset_init_smp() with
>   node_states[N_MEMORY]
> 
> take 3:
> + fix up comments and top level cpuset tracking of nodes
>   with memory [instead of on-line nodes].
> + maybe I got them all this time?
> 
> 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
> 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.
> 
> Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
> 
>  include/linux/cpuset.h |    2 -
>  kernel/cpuset.c        |   51 +++++++++++++++++++++++++++++++------------------
>  2 files changed, 34 insertions(+), 19 deletions(-)

Small typo fix which prevents build with !CPUSETS.

---
FYI: I noticed that oldconfig on 2.6.23-rc1-mm1 with CPUSETS=y disables
CPUSETS because of the introduction of CONFIG_CONTAINERS :(

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

diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index f8f4f68..d01b1bc 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -92,7 +92,7 @@ static inline nodemask_t cpuset_mems_allowed(struct task_struct *p)
 	return node_possible_map;
 }
 
-#define cpuset_current_mems_allowed (node_states[N_MEMORY))
+#define cpuset_current_mems_allowed (node_states[N_MEMORY])
 static inline void cpuset_init_current_mems_allowed(void) {}
 static inline void cpuset_update_task_memory_state(void) {}
 #define cpuset_nodes_subset_current_mems_allowed(nodes) (1)

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

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