PATCH 14/15 Mempolicy: support mpol=local tmpfs mount option
Against: 2.6.25-rc8-mm1
For tmpfs/shmem shared policies, MPOL_DEFAULT is not necessarily
equivalent to "local allocation". Because shared policies are at
the same "scope" level [see Documentation/vm/numa_memory_policy.txt],
as vma policies MPOL_DEFAULT means "fall back to current task policy".
This patch extends the memory policy string parsing function to
display "local" for MPOL_PREFERRED + MPOL_F_LOCAL. This allows
one to specify local allocation as the default policy for shared
memory areas via the tmpfs mpol mount option, regardless of the
current task's policy.
Also, "local" is now displayed for this policy. This patch allows
us to accept the same input format as the display.
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@xxxxxx>
mm/mempolicy.c | 25 +++++++++++++++++--------
1 file changed, 17 insertions(+), 8 deletions(-)
Index: linux-2.6.25-rc8-mm1/mm/mempolicy.c
===================================================================
--- linux-2.6.25-rc8-mm1.orig/mm/mempolicy.c 2008-04-02 17:52:11.000000000 -0400
+++ linux-2.6.25-rc8-mm1/mm/mempolicy.c 2008-04-02 17:52:20.000000000 -0400
@@ -1952,7 +1952,7 @@ void numa_default_policy(void)
/*
* "local" is pseudo-policy: MPOL_PREFERRED with MPOL_F_LOCAL flag
- * Used only for mpol_to_str()
+ * Used only for mpol_parse_str() and mpol_to_str()
*/
#define MPOL_LOCAL (MPOL_INTERLEAVE + 1)
static const char * const policy_types[] =
@@ -1991,21 +1991,16 @@ int mpol_parse_str(char *str, unsigned s
if (flags)
*flags++ = '\0'; /* terminate mode string */
- for (i = 0; i < MPOL_MAX; i++) {
+ for (i = 0; i <= MPOL_LOCAL; i++) {
if (!strcmp(str, policy_types[i])) {
*mode = i;
break;
}
}
- if (i == MPOL_MAX)
+ if (i > MPOL_LOCAL)
goto out;
switch (*mode) {
- case MPOL_DEFAULT:
- /* Don't allow a nodelist nor flags */
- if (!nodelist && !flags)
- err = 0;
- break;
case MPOL_PREFERRED:
/* Insist on a nodelist of one node only */
if (nodelist) {
@@ -2028,6 +2023,20 @@ int mpol_parse_str(char *str, unsigned s
if (!nodelist)
*policy_nodes = node_states[N_HIGH_MEMORY];
err = 0;
+ break;
+ default:
+ /*
+ * MPOL_DEFAULT or MPOL_LOCAL
+ * Don't allow a nodelist nor flags
+ */
+ if (!nodelist && !flags)
+ err = 0;
+ if (*mode == MPOL_DEFAULT)
+ goto out;
+ /* else MPOL_LOCAL */
+ *mode = MPOL_PREFERRED;
+ nodes_clear(*policy_nodes);
+ break;
}
*mode_flags = 0;
--
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