[PATCH 11/31] mm/mpol: Make MPOL_LOCAL a real policy

From: Peter Zijlstra
Date: Thu Oct 25 2012 - 09:14:46 EST


Make MPOL_LOCAL a real and exposed policy such that applications that
relied on the previous default behaviour can explicitly request it.

Requested-by: Christoph Lameter <cl@xxxxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Lee Schermerhorn <Lee.Schermerhorn@xxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/uapi/linux/mempolicy.h | 1 +
mm/mempolicy.c | 9 ++++++---
2 files changed, 7 insertions(+), 3 deletions(-)

Index: tip/include/uapi/linux/mempolicy.h
===================================================================
--- tip.orig/include/uapi/linux/mempolicy.h
+++ tip/include/uapi/linux/mempolicy.h
@@ -20,6 +20,7 @@ enum {
MPOL_PREFERRED,
MPOL_BIND,
MPOL_INTERLEAVE,
+ MPOL_LOCAL,
MPOL_MAX, /* always last member of enum */
};

Index: tip/mm/mempolicy.c
===================================================================
--- tip.orig/mm/mempolicy.c
+++ tip/mm/mempolicy.c
@@ -269,6 +269,10 @@ static struct mempolicy *mpol_new(unsign
(flags & MPOL_F_RELATIVE_NODES)))
return ERR_PTR(-EINVAL);
}
+ } else if (mode == MPOL_LOCAL) {
+ if (!nodes_empty(*nodes))
+ return ERR_PTR(-EINVAL);
+ mode = MPOL_PREFERRED;
} else if (nodes_empty(*nodes))
return ERR_PTR(-EINVAL);
policy = kmem_cache_alloc(policy_cache, GFP_KERNEL);
@@ -2371,7 +2375,6 @@ void numa_default_policy(void)
* "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
* Used only for mpol_parse_str() and mpol_to_str()
*/
-#define MPOL_LOCAL MPOL_MAX
static const char * const policy_modes[] =
{
[MPOL_DEFAULT] = "default",
@@ -2424,12 +2427,12 @@ int mpol_parse_str(char *str, struct mem
if (flags)
*flags++ = '\0'; /* terminate mode string */

- for (mode = 0; mode <= MPOL_LOCAL; mode++) {
+ for (mode = 0; mode < MPOL_MAX; mode++) {
if (!strcmp(str, policy_modes[mode])) {
break;
}
}
- if (mode > MPOL_LOCAL)
+ if (mode >= MPOL_MAX)
goto out;

switch (mode) {


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