The patch titled
Subject: cgroup: release css->id after css_free
has been removed from the -mm tree. Its filename was
cgroup-release-css-id-after-css_free.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Subject: cgroup: release css->id after css_free
Currently, we release css->id in css_release_work_fn, right before calling
css_free callback, so that when css_free is called, the id may have
already been reused for a new cgroup.
I am going to use css->id to create unique names for per memcg kmem
caches. Since kmem caches are destroyed only on css_free, I need css->id
to be freed after css_free was called to avoid name clashes. This patch
therefore moves css->id removal to css_free_work_fn. To prevent
css_from_id from returning a pointer to a stale css, it makes
css_release_work_fn replace the css ptr at css_idr:css->id with NULL.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Dave Chinner <david@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/cgroup.c | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)
diff -puN kernel/cgroup.c~cgroup-release-css-id-after-css_free kernel/cgroup.c
--- a/kernel/cgroup.c~cgroup-release-css-id-after-css_free
+++ a/kernel/cgroup.c
@@ -4373,16 +4373,20 @@ static void css_free_work_fn(struct work
{
struct cgroup_subsys_state *css =
container_of(work, struct cgroup_subsys_state, destroy_work);
+ struct cgroup_subsys *ss = css->ss;
struct cgroup *cgrp = css->cgroup;
percpu_ref_exit(&css->refcnt);
- if (css->ss) {
+ if (ss) {
/* css free path */
+ int id = css->id;
+
if (css->parent)
css_put(css->parent);
- css->ss->css_free(css);
+ ss->css_free(css);
+ cgroup_idr_remove(&ss->css_idr, id);
cgroup_put(cgrp);
} else {
/* cgroup free path */
@@ -4434,7 +4438,7 @@ static void css_release_work_fn(struct w
if (ss) {
/* css release path */
- cgroup_idr_remove(&ss->css_idr, css->id);
+ cgroup_idr_replace(&ss->css_idr, NULL, css->id);
if (ss->css_released)
ss->css_released(css);
} else {
_
Patches currently in -mm which might be from vdavydov@xxxxxxxxxxxxx are
origin.patch
mm-vmscan-fix-the-page-state-calculation-in-too_many_isolated.patch
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