Mem Policy: add MPOL_F_MEMS_ALLOWED get_mempolicy() flag

Allow an application to query the memories allowed by its context.

Updated numa_memory_policy.txt to mention that applications can use this to
obtain allowed memories for constructing valid policies.

TODO:  update out-of-tree libnuma wrapper[s], or maybe add a new
wrapper--e.g.,  numa_get_mems_allowed() ?

Also, update numa syscall man pages.

Tested with memtoy V>=0.13.

Signed-off-by:  Lee Schermerhorn <lee.schermerhorn@hp.com>
Acked-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index a020eb2d4e2a..7e9698ec839b 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -19,6 +19,7 @@
 /* Flags for get_mem_policy */
 #define MPOL_F_NODE     (1<<0)  /* return next IL mode instead of node mask */
 #define MPOL_F_ADDR     (1<<1)  /* look up vma using address */
+#define MPOL_F_MEMS_ALLOWED (1<<2) /* return allowed memories */
 
 /* Flags for mbind */
 #define MPOL_MF_STRICT  (1<<0)  /* Verify existing pages in the mapping */