From 4c50bc0116cf3cc35e7152d6a8424b4db65f52d6 Mon Sep 17 00:00:00 2001 From: David Rientjes Date: Mon, 28 Apr 2008 02:12:30 -0700 Subject: 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 . Cc: Paul Jackson Cc: Christoph Lameter Cc: Lee Schermerhorn Cc: Andi Kleen Signed-off-by: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mempolicy.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h index 07350d7b8d9..02b11efd706 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 */ -- cgit v1.2.3