Le 10/02/2022 à 23:49, Yury Norov a écrit :
do_migrate_pages() calls nodes_weight() to compare the weight
of nodemask with a given number. We can do it more efficiently with
nodes_weight_eq() because conditional nodes_weight() may stop
traversing the nodemask earlier, as soon as condition is (or is not)
met.
Signed-off-by: Yury Norov <yury.norov@xxxxxxxxx>
---
mm/mempolicy.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 7c852793d9e8..56efd00b1b6e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1154,7 +1154,7 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
* [0-7] - > [3,4,5] moves only 0,1,2,6,7.
*/
- if ((nodes_weight(*from) != nodes_weight(*to)) &&
+ if (!nodes_weight_eq(*from, nodes_weight(*to)) &&
(node_isset(s, *to)))
Hi,
I've not looked in details, but would it make sense to hoist the
"(nodes_weight(*from) != nodes_weight(*to))" test out of the
for_each_node_mask() to compute it only once?
'from' and 'to' look unmodified in the loop.
Just my 2c,
CJ
continue;
