On 6/17/23 04:30, Miaohe Lin wrote:
The tsk->mems_allowed is changed before calling mpol_rebind_task() and
being reassigned right after it. But tsk->mems_allowed is not needed
inside mpol_rebind_task(). So remove unneeded tsk->mems_allowed modify
via nodes_or() here.
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
---
kernel/cgroup/cpuset.c | 1 -
1 file changed, 1 deletion(-)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 58e6f18f01c1..33a429c1179f 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1941,7 +1941,6 @@ static void cpuset_change_task_nodemask(struct task_struct *tsk,
local_irq_disable();
write_seqcount_begin(&tsk->mems_allowed_seq);
- nodes_or(tsk->mems_allowed, tsk->mems_allowed, *newmems);
mpol_rebind_task(tsk, newmems);
tsk->mems_allowed = *newmems;
That line was inserted by commit cc9a6c8776615 ("cpuset: mm: reduce
large amounts of memory barrier related damage v3"). At first glance, it
does looks like it is not necessary. However, I am not sure if a race is
possible that will produce a false failure because of missing this line.
My 2 cents.
Cheers,
Longman
