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authorDavid Rientjes <rientjes@google.com>2008-04-28 02:12:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-28 08:58:19 -0700
commit4c50bc0116cf3cc35e7152d6a8424b4db65f52d6 (patch)
tree99c617602cc1946fc86b48e9a35f14f9f354cf67 /include/linux/mempolicy.h
parent7ea931c9fc80c4d0a4306c30ec92eb0f1d922a0b (diff)
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mempolicy: add MPOL_F_RELATIVE_NODES flag
Adds another optional mode flag, MPOL_F_RELATIVE_NODES, that specifies nodemasks passed via set_mempolicy() or mbind() should be considered relative to the current task's mems_allowed. When the mempolicy is created, the passed nodemask is folded and mapped onto the current task's mems_allowed. For example, consider a task using set_mempolicy() to pass MPOL_INTERLEAVE | MPOL_F_RELATIVE_NODES with a nodemask of 1-3. If current's mems_allowed is 4-7, the effected nodemask is 5-7 (the second, third, and fourth node of mems_allowed). If the same task is attached to a cpuset, the mempolicy nodemask is rebound each time the mems are changed. Some possible rebinds and results are: mems result 1-3 1-3 1-7 2-4 1,5-6 1,5-6 1,5-7 5-7 Likewise, the zonelist built for MPOL_BIND acts on the set of zones assigned to the resultant nodemask from the relative remap. In the MPOL_PREFERRED case, the preferred node is remapped from the currently effected nodemask to the relative nodemask. This mempolicy mode flag was conceived of by Paul Jackson <pj@sgi.com>. Cc: Paul Jackson <pj@sgi.com> Cc: Christoph Lameter <clameter@sgi.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mempolicy.h')
-rw-r--r--include/linux/mempolicy.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 07350d7b8d96..02b11efd7066 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -25,12 +25,13 @@ enum {
/* Flags for set_mempolicy */
#define MPOL_F_STATIC_NODES (1 << 15)
+#define MPOL_F_RELATIVE_NODES (1 << 14)
/*
* MPOL_MODE_FLAGS is the union of all possible optional mode flags passed to
* either set_mempolicy() or mbind().
*/
-#define MPOL_MODE_FLAGS (MPOL_F_STATIC_NODES)
+#define MPOL_MODE_FLAGS (MPOL_F_STATIC_NODES | MPOL_F_RELATIVE_NODES)
/* Flags for get_mempolicy */
#define MPOL_F_NODE (1<<0) /* return next IL mode instead of node mask */