Documentation/vm/numa_memory_policy.txt

83 	VMA policies are shared between all tasks that share a virtual address
102     Shared Policy:  Conceptually, shared policies apply to "memory objects"
103     mapped shared into one or more tasks' distinct address spaces.  An
104     application installs a shared policies the same way as VMA policies--using
106     the shared object.  However, unlike VMA policies, which can be considered
107     to be an attribute of a range of a task's address space, shared policies
108     apply directly to the shared object.  Thus, all tasks that attach to the
109     object share the policy, and all pages allocated for the shared object,
110     by any task, will obey the shared policy.
112 	As of 2.6.22, only shared memory segments, created by shmget() or
113 	mmap(MAP_ANONYMOUS|MAP_SHARED), support shared policy.  When shared
117 	shmem segments were never "hooked up" to the shared policy support.
119 	for shared policy has not been completed.
123 	policy installed on the virtual address range backed by the shared
124 	file mapping.  Rather, shared page cache pages, including pages backing
128 	The shared policy infrastructure supports different policies on subset
129 	ranges of the shared object.  However, Linux still splits the VMA of
131 	Thus, different tasks that attach to a shared memory segment can have
132 	different VMA configurations mapping that one shared object.  This
134 	a shared memory region, when one task has installed shared policy on
197 	    For allocation of anonymous pages and shared memory pages,
343 4) Shared policies require special consideration.  One task can replace a
344    shared memory policy while another task, with a distinct mmap_sem, is
346    potential race, the shared policy infrastructure adds an extra reference
347    to the shared policy during lookup while holding a spin lock on the shared
350    extra reference on shared policies in the same query/allocation paths
351    used for non-shared policies.  For this reason, shared policies are marked
353    for shared policies.
356    shared policies in a tree structure under spinlock, shared policies are
358    true for shared policies on shared memory regions shared by tasks running
360    falling back to task or system default policy for shared memory regions,
361    or by prefaulting the entire shared memory region into memory and locking
368 some shared object mapped into the calling task's address space.
404 Install VMA/Shared Policy for a Range of Task's Address Space
425 + set the shared policy for a shared memory segment via mbind(2)
446 in two cpusets share access to a memory region, such as shared memory segments
448 any of the tasks install shared policy on the region, only nodes whose
452 be attaching to the shared region.  Furthermore, if the cpusets' allowed