2021-12-14 00:46:20

by Wei Yang

Subject: [Patch v2] cgroup: return early if it is already on preloaded list

If a cset is already on preloaded list, this means we have already setup
this cset properly for migration.

This patch just relocate the root cgrp lookup which isn't used anyway
when the cset is already on the preloaded list.

[[email protected]: rephrase the commit log]

Signed-off-by: Wei Yang <[email protected]>

---
v2: rephrase commit log
---
kernel/cgroup/cgroup.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 452a723d4a36..2cf729afe834 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2648,11 +2648,11 @@ void cgroup_migrate_add_src(struct css_set *src_cset,
if (src_cset->dead)
return;

- src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);
-
if (!list_empty(&src_cset->mg_preload_node))
return;

+ src_cgrp = cset_cgroup_from_root(src_cset, dst_cgrp->root);
+
WARN_ON(src_cset->mg_src_cgrp);
WARN_ON(src_cset->mg_dst_cgrp);
WARN_ON(!list_empty(&src_cset->mg_tasks));
--
2.33.1

2021-12-14 19:45:58

by Tejun Heo

Subject: Re: [Patch v2] cgroup: return early if it is already on preloaded list

On Tue, Dec 14, 2021 at 12:46:07AM +0000, Wei Yang wrote:
> If a cset is already on preloaded list, this means we have already setup
> this cset properly for migration.
>
> This patch just relocate the root cgrp lookup which isn't used anyway
> when the cset is already on the preloaded list.
>
> [[email protected]: rephrase the commit log]
>
> Signed-off-by: Wei Yang <[email protected]>

Applied to cgroup/for-5.17.

Thanks.

--
tejun