[PATCH 04/12] mm/mempolicy: allow preferred code to take a nodemask

From: Ben Widawsky
Date: Tue Jun 30 2020 - 17:25:58 EST


From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

Create a helper function (mpol_new_preferred_many()) which is usable
both by the old, single-node MPOL_PREFERRED and the new
MPOL_PREFERRED_MANY.

Enforce the old single-node MPOL_PREFERRED behavior in the "new"
version of mpol_new_preferred() which calls mpol_new_preferred_many().

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Ben Widawsky <ben.widawsky@xxxxxxxxx>
---
mm/mempolicy.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 33bf29ddfab2..1ad6e446d8f6 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -203,17 +203,30 @@ static int mpol_new_interleave(struct mempolicy *pol, const nodemask_t *nodes)
return 0;
}

-static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
+static int mpol_new_preferred_many(struct mempolicy *pol,
+ const nodemask_t *nodes)
{
if (!nodes)
pol->flags |= MPOL_F_LOCAL; /* local allocation */
else if (nodes_empty(*nodes))
return -EINVAL; /* no allowed nodes */
else
- pol->v.preferred_nodes = nodemask_of_node(first_node(*nodes));
+ pol->v.preferred_nodes = *nodes;
return 0;
}

+static int mpol_new_preferred(struct mempolicy *pol, const nodemask_t *nodes)
+{
+ if (nodes) {
+ /* MPOL_PREFERRED can only take a single node: */
+ nodemask_t tmp = nodemask_of_node(first_node(*nodes));
+
+ return mpol_new_preferred_many(pol, &tmp);
+ }
+
+ return mpol_new_preferred_many(pol, NULL);
+}
+
static int mpol_new_bind(struct mempolicy *pol, const nodemask_t *nodes)
{
if (nodes_empty(*nodes))
--
2.27.0