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>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 3a45b7d..ccbdb22 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -526,8 +526,18 @@
struct mempolicy *pol = current->mempolicy;
cpuset_update_task_memory_state();
- if (flags & ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR))
+ if (flags &
+ ~(unsigned long)(MPOL_F_NODE|MPOL_F_ADDR|MPOL_F_MEMS_ALLOWED))
return -EINVAL;
+
+ if (flags & MPOL_F_MEMS_ALLOWED) {
+ if (flags & (MPOL_F_NODE|MPOL_F_ADDR))
+ return -EINVAL;
+ *policy = 0; /* just so it's initialized */
+ *nmask = cpuset_current_mems_allowed;
+ return 0;
+ }
+
if (flags & MPOL_F_ADDR) {
down_read(&mm->mmap_sem);
vma = find_vma_intersection(mm, addr, addr+1);