- current->mems_allowed_change_disable++;
-
- /*
- * ensure that reading mems_allowed and mempolicy happens after the
- * update of ->mems_allowed_change_disable.
- *
- * the write-side task finds ->mems_allowed_change_disable is not 0,
- * and knows the read-side task is reading mems_allowed or mempolicy,
- * so it will clear old bits lazily.
- */
- smp_mb();