diff options
| author | David Rientjes <rientjes@google.com> | 2008-04-28 02:12:30 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2008-04-28 08:58:19 -0700 |
| commit | 4c50bc0116cf3cc35e7152d6a8424b4db65f52d6 (patch) | |
| tree | 99c617602cc1946fc86b48e9a35f14f9f354cf67 /mm/shmem.c | |
| parent | 7ea931c9fc80c4d0a4306c30ec92eb0f1d922a0b (diff) | |
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 'mm/shmem.c')
| -rw-r--r-- | mm/shmem.c | 6 |
1 files changed, 6 insertions, 0 deletions
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 */ |