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| author |   Vladimir Davydov <vdavydov@parallels.com> | 2015-02-12 14:59:26 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2015-02-12 18:54:09 -0800 |
| commit | 01e586598b224d1a427acd8a7afa0b21e879d3a7 (patch) | |
| tree | cf53ecf130f08a453f3a70963dd3fd6741fee449 /kernel | |
| parent | slab: link memcg caches of the same kind into a list (diff) | |
| download | linux-dev-01e586598b224d1a427acd8a7afa0b21e879d3a7.tar.xz linux-dev-01e586598b224d1a427acd8a7afa0b21e879d3a7.zip | |
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@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Dave Chinner <david@fromorbit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 04cfe8ace520..d5f6ec251fb2 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -4373,16 +4373,20 @@ static void css_free_work_fn(struct work_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 work_struct *work) 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 { |