admin-guide/mm/numa_memory_policy.rst

19 which is an administrative mechanism for restricting the nodes from which
42 	allocations across all nodes with "sufficient" memory, so as
166 an optional set of nodes.  The mode determines the behavior of the
168 and the optional set of nodes can be viewed as the arguments to the
190 	does not use the optional set of nodes.
192 	It is an error for the set of nodes specified for this policy to
197 	nodes specified by the policy.  Memory will be allocated from
204 	allocation fails, the kernel will search other nodes, in order
224 	page granularity, across the nodes specified in the policy.
229 	Interleave mode indexes the set of nodes specified by the
232 	nodes specified by the policy.  It then attempts to allocate a
239 	the set of nodes specified by the policy using a node counter
242 	This will tend to spread the pages out over the nodes
253 	nodes changes after the memory policy has been defined.
256 	change in the set of allowed nodes, the node (Preferred) or
258 	allowed nodes.  This may result in nodes being used that were
261 	With this flag, if the user-specified nodes overlap with the
262 	nodes allowed by the task's cpuset, then the memory policy is
263 	applied to their intersection.  If the two sets of nodes do not
269 	over nodes 3, 4, and 5.  With this flag, however, since only node
271 	occurs over that node.  If no nodes from the user's nodemask are
282 	set of allowed nodes.  The kernel stores the user-passed nodemask,
283 	and if the allowed nodes changes, then that original nodemask will
284 	be remapped relative to the new set of allowed nodes.
288 	nodes, the node (Preferred) or nodemask (Bind, Interleave) is
289 	remapped to the new set of allowed nodes.  That remap may not
291 	set of allowed nodes upon successive rebinds: a nodemask of
293 	allowed nodes is restored to its original state.
297 	nodes.  In other words, if nodes 0, 2, and 4 are set in the user's
299 	Bind or Interleave case, the third and fifth) nodes in the set of
300 	allowed nodes.  The nodemask passed by the user represents nodes
301 	relative to task or VMA's set of allowed nodes.
303 	If the user's nodemask includes nodes that are outside the range
304 	of the new set of allowed nodes (for example, node 5 is set in
305 	the user's nodemask when the set of allowed nodes is only 0-3),
312 	interleave now occurs over nodes 3,5-7.  If the cpuset's mems
313 	then change to 0,2-3,5, then the interleave occurs over nodes
320 	memory nodes 0 to N-1, where N is the number of memory nodes the
322 	set of memory nodes allowed by the task's cpuset, as that may
347 and NUMA nodes.  "Usage" here means one of the following:
357    BIND policy nodemask is used, by reference, to filter ineligible nodes.
394    on different NUMA nodes.  This extra overhead can be avoided by always
421 specified by the 'mode' argument and the set of nodes defined by
478 that require a node or set of nodes, the nodes are restricted to the set of
479 nodes whose memories are allowed by the cpuset constraints.  If the nodemask
480 specified for the policy contains nodes that are not allowed by the cpuset and
481 MPOL_F_RELATIVE_NODES is not used, the intersection of the set of nodes
482 specified for the policy and the set of nodes with memory is used.  If the
484 installed.  If MPOL_F_RELATIVE_NODES is used, the policy's nodes are mapped
485 onto and folded into the task's set of allowed nodes as previously described.
490 any of the tasks install shared policy on the region, only nodes whose