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 --- mm/shmem.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'mm/shmem.c') diff --git a/mm/shmem.c b/mm/shmem.c index 3e9fda0ca47..9435f298dd7 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -1128,6 +1128,12 @@ static int shmem_parse_mpol(char *value, unsigned short *policy, if (flags) { if (!strcmp(flags, "static")) *mode_flags |= MPOL_F_STATIC_NODES; + if (!strcmp(flags, "relative")) + *mode_flags |= MPOL_F_RELATIVE_NODES; + + if ((*mode_flags & MPOL_F_STATIC_NODES) && + (*mode_flags & MPOL_F_RELATIVE_NODES)) + err = 1; } out: /* Restore string for error message */ -- cgit v1.2.3