diff mbox series

[01/18] mm/mempolicy: Add comment for missing LOCAL

Message ID 20200619162414.1052234-2-ben.widawsky@intel.com (mailing list archive)
State New, archived
Headers show
Series multiple preferred nodes | expand

Commit Message

Ben Widawsky June 19, 2020, 4:23 p.m. UTC 
MPOL_LOCAL is a bit weird because it is simply a different name for an
existing behavior (preferred policy with no node mask). It has been this
way since it was added here:
commit 479e2802d09f ("mm: mempolicy: Make MPOL_LOCAL a real policy")

It is so similar to MPOL_PREFERRED in fact that when the policy is
created in mpol_new, the mode is set as PREFERRED, and an internal state
representing LOCAL doesn't exist.

To prevent future explorers from scratching their head as to why
MPOL_LOCAL isn't defined in the mpol_ops table, add a small comment
explaining the situations.

Cc: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
---
 mm/mempolicy.c | 1 +
 1 file changed, 1 insertion(+)
diff mbox series

Patch

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 381320671677..36ee3267c25f 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -427,6 +427,7 @@  static const struct mempolicy_operations mpol_ops[MPOL_MAX] = {
 		.create = mpol_new_bind,
 		.rebind = mpol_rebind_nodemask,
 	},
+	/* MPOL_LOCAL is converted to MPOL_PREFERRED on policy creation */
 };
 
 static int migrate_page_add(struct page *page, struct list_head *pagelist,