mempolicy_nodemask_intersects() is used in oom case to check if a
task may have memory allocated on some memory nodes.
MPOL_INTERLEAVE has set a nodemask, which is not a forced requirement,
but just a hint for chosing a node to allocate memory from, and the
task may have memory allocated on other nodes than this nodemask. So
skip the check.
Suggested-by: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
---
mm/mempolicy.c | 24 ++++--------------------
1 file changed, 4 insertions(+), 20 deletions(-)
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d79fa29..1964cca 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2098,7 +2098,7 @@ bool init_nodemask_of_mempolicy(nodemask_t *mask)
*
* If tsk's mempolicy is "default" [NULL], return 'true' to indicate default
* policy. Otherwise, check for intersection between mask and the policy
- * nodemask for 'bind' or 'interleave' policy. For 'preferred' or 'local'
+ * nodemask for 'bind' policy. For 'interleave', 'preferred' or 'local'
* policy, always return true since it may allocate elsewhere on fallback.
*
* Takes task_lock(tsk) to prevent freeing of its mempolicy.
@@ -2111,29 +2111,13 @@ bool mempolicy_nodemask_intersects(struct task_struct *tsk,
if (!mask)
return ret;
+
task_lock(tsk);
mempolicy = tsk->mempolicy;
- if (!mempolicy)
- goto out;
-
- switch (mempolicy->mode) {
- case MPOL_PREFERRED:
- /*
- * MPOL_PREFERRED and MPOL_F_LOCAL are only preferred nodes to
- * allocate from, they may fallback to other nodes when oom.
- * Thus, it's possible for tsk to have allocated memory from
- * nodes in mask.
- */
- break;
- case MPOL_BIND:
- case MPOL_INTERLEAVE:
+ if (mempolicy && mempolicy->mode == MPOL_BIND)
ret = nodes_intersects(mempolicy->v.nodes, *mask);
- break;
- default:
- BUG();
- }
-out:
task_unlock(tsk);
+
return ret;
}
--
2.7.4
